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<?xml version="1.0" encoding="utf-8" standalone="yes"?>
<feed xmlns="http://www.w3.org/2005/Atom" xml:lang="en-us">
<title>Benjamin Jacobs</title>
<link rel="self" type="application/atom+xml" hreflang="" href="gemini://benjaminja.com/feed.xml" />
<link rel="alternate" type="text/gemini" hreflang="" href="gemini://benjaminja.com/" /><id>/</id>
<updated>2024-04-25T05:28:30Z</updated>
<generator>Hugo 0.125.4</generator>
<entry>
<title><![CDATA[Converting from teensy to arduino]]></title>
<link rel="alternate" type="text/gemini" hreflang="" href="gemini://benjaminja.com/log/2024/05/21-station_conversion/" />
<id>gemini://benjaminja.com/log/2024/05/21-station_conversion/</id>
<updated>2024-05-21T22:13:26Z</updated>
<summary type="gemini"><![CDATA[For the past few days, I have been converting my weather station firmware to use an Arduino Atmega328P chip instead of a teensy Arm Cortex M7 chip. In my last post, I found that the teensy is significantly overpowered for the job and it could be contributing to why the temperature readings are consistently so high.
]]></summary><content type="gemini"><![CDATA[For the past few days, I have been converting my weather station firmware to use an Arduino Atmega328P chip instead of a teensy Arm Cortex M7 chip. In my last post, I found that the teensy is significantly overpowered for the job and it could be contributing to why the temperature readings are consistently so high.
I want to discuss the logic that the station does and how it has become difficult to squeeze that same logic into a much smaller device.
On the teensy, the logic was split into a few parts:
1. Interrupt when the rain sensor senses 0.01in of rain.
2. Interrupt when the anemometer turns 180Āŗ.
3. Keep a history of past hour of rainfall.
4. Keep a history of the past 10 minutes of wind data (this includes average and gusts).
5. Send all the information back to the base station when it needs it.
This is quite a bit of things for the station to do and is definitely way too much for the Arduino to handle. Instead of keeping a history of the data on the station, the base station will do most of the processing. I figured this would be a relatively easy process, but I have forgotten just how under powered the Arduino is.
The Arduino has 32kB of flash and 2kB of ram. 32kB is pretty small, but that isnāt really a big deal. You have to have a really big program to surpass 32kB. I donāt even think the program for the teensy was bigger than 32kB. The real problem is with the ram. 2048 bytes of ram is all you get. Thatās including static variables, stack variables, and the heap.
When you compile for the arduino, it gives you a helpful graph saying how much ram and flash your program uses. For flash, it just doesnāt need to get bigger than 32kB. The ram is a different story though. The graph that is provided for ram shows only static variables that are pre-allocated. So if you used 1kB of ram in the graph, then you really only have 1kB of ram for the stack and heap. So you really need to be careful about memory at all times.
> This is one of the reasons why I donāt particularly like C++ for embedded since when using classes you sometimes never really know how much memory you might end up using. Though the embedded community has made C++ feel a lot better than I think how modern C++ feels. I canāt wait for embedded Zig to mature, but it is still at the point where only like 5 boards are supported, and even then, only registers are available which make programming a nightmare. (Iāve really only tried to get into embedded Zig once, and probably missed a bunch of things. I would love to be proved wrong about embedded Zig)
With my adaption to Arduino, I have reduced the responsibilities significantly for the station.
1. Interrupt when the rain sensor senses 0.01in of rain.
2. Interrupt when the anemometer turns 180Āŗ.
3. Store the number of rain ticks since the last update.
4. Store the number of wind ticks and wind directions since the last update (up to 1 minute worth)
5. Send all the information back to the base station when it requests it.
While the Arduino has the same basic responsibilities, it is now performing less calculations and storing less data in ram. The biggest changes are to the wind. Before, the teensy stored 600 floats/uint8 for the wind gust/directions at a rate of 1 sample per second for 10 minutes. That alone is 3000 bytes of data and 1.5 times the total ram capacity of the Arduino. And that is not including wind averages.
Iāve since realized that I could significantly save space by storing only the last minute of data (60 samples) and instead of calculating the speed on the chip, it just counts the number of ticks during the sample. I could store each sample as a uint8, and store the wind direction also as a uint8. This makes the cache only 128 bytes long.
You might be thinking to yourself āSelf, how does one get 360Āŗ to fit in 255?ā Iām glad you asked! My weather vane can only read 8 cardinal directions. āGreat, so the direction can fit easily in a byte!ā Not exactly, 10 times a second I take a reading from the weather vane. Convert it to x/y components and average it out for the sample. I then use an atan2 LUT to convert the x/y component back into an angle. The LUT is a 21x21 table ranging from [-1.0, 1.0].
=> /log/2024/05/21-station_conversion/Figure_1.png š¼ Image of the LUTāColorized
Because the LUT is built with steps of 0.1, there are 441 possible outputs, but there are only 232 angles that are produced. So instead of outputting the angle I output the value for another LUT which converts from values [0,232) to [-174,180]. This way I can store a more accurate wind direction within a single byte. The base station will have to convert the angle index back into a real angle, but I feel like it is a pretty interesting way to get more detail out of the sensor.
]]></content>
<category term="projects" label="Projects" scheme="gemini://benjaminja.com/tags/projects/" />
<category term="weather-station" label="Weather-Station" scheme="gemini://benjaminja.com/tags/weather-station/" />
<published>2024-05-21T22:13:26Z</published></entry>
<entry>
<title><![CDATA[Weatherstation Update]]></title>
<link rel="alternate" type="text/gemini" hreflang="" href="gemini://benjaminja.com/log/2024/05/16-weatherstation-update/" />
<id>gemini://benjaminja.com/log/2024/05/16-weatherstation-update/</id>
<updated>2024-05-16T17:55:36Z</updated>
<summary type="gemini"><![CDATA[It has been a little while since I last wrote about my weather stationāalmost a whole year in fact. I wrote about how I would go about communicating between my raspberry pi and my micro controller.
]]></summary><content type="gemini"><![CDATA[=> /log/2024/05/16-weatherstation-update/24-03-18_13-30-12_fly_.jpg š¼ Photo of the weather station
It has been a little while since I last wrote about my weather stationāalmost a whole year in fact. I wrote about how I would go about communicating between my raspberry pi and my micro controller. I decided I would use CAN bus to do all the communicating. It turns out though that CAN is really difficult and designed to work well when you have multiple devices communicating over the same wire. Think long distance i2c. Since Iām just doing peer to peer, CAN ends up being a bit over complicated for my use case.
Shortly after writing my post, [Fripster] sent me a message saying that I might be better off using RS422. He was definitely right and I switched over to that right away.
=> gopher://fripster.ydns.eu Fripster
## What is RS422
In my project, Iām specifically using differential TTL (transistor-transistor logic) where each UART is split into two twisted wires where one is + and the other is -. At the receiving end, the pair is combined back together into a single signal. These twisted pairs make it so that the signal can go for a significantly longer distance without signal degradation. There has been a ton of work done to figure out how and why it works, but itās basically just magic to me.
## S-Code
RS422 isnāt a protocol on its own. It is closer to a specification on how to physically connect two devices together. Iām not even sure if there is a standardized voltage designated for it, and if there is, Iām definitely not using it.
In order to actually communicate between the two devices, I came up with a binary extension to G-Code I called S-Code (I think it was short for Serial Code). Instead of commanding a CNC machine, I send custom codes to request codes be sent back or to save configurations.
The codes can be either in traditional g-code style, or in my own custom binary format. It supports 8, 16, 32, 64 bit integers, strings, and 32 or 64 bit floats. At the end of every binary code is an 8-bit crc.
You can learn more about it at [github.com/ttocsneb/scode].
=> https://github.com/ttocsneb/scode github.com/ttocsneb/scode
## Temperature Problems
I have been able to get the weather station up and running. It collects data, can display current conditions, and most importantly, is usable by non-technical people. Almost everything seems to be working with it. There is just one itsy bitsy problem. The temperature is readings are too high.
=> /log/2024/05/16-weatherstation-update/StationTemperatureAdjustmentGraph.png š¼ Graph of the temperature readings from the airport, my station, and my station adjusted by a constant value
In the above graph, you can see that my station is higher than the airport temperatures by about 8ĀŗF (~5ĀŗC) on average. I ended up applying a constant adjustment to the temperature sensor to combat the issue. Just today, it was reading 72ĀŗF (22ĀŗC). There is absolutely no way it was 80ĀŗF (27ĀŗC) today. The constant adjustment isnāt a great solution though. You can see that the adjusted temperature can be higher than the airport during the day, and cooler during the night by a few degrees. Since the airport is by the lake, it is possible that the actual temperature differences between me and the airport are just a few degrees different, but I donāt know. I feel like there is something going on with the sensor or setup.
I have a few theories why the temperature could be wrong:
1. The teensy is generating too much heat, affecting the readings.
2. The Direct sunlight is increasing the temperature of the enclosure even though it is well ventilated.
3. Waterproofing the chip could have caused problems with the sensor. (I did not waterproof the sensor itself, just around it, but I could have made a mistake)
4. The sensor is faulty. I could just be unlucky and got a chip that wasnāt well calibrated.
I have a feeling that the issue is coming from the teensy being too hot. When developing the software, I noticed that the chip gets warm to the touch. Itās not really something that I have noticed on other MCUs, though seeing that the Cortex M-7 is clocked at 600MHz, itās starting to make sense why it gets a little warm. If it is warm to my touch, then it would make sense why it could affect the temperature sensors readings.
The ground plane on the circuit board covers the whole thing, so the circuit board is acting like a heat sync and since the sensor is connected to ground, a larger thermal load could be pumping heat into the sensor.
This doesnāt really explain why the actual readings would at times be close to the real temperature. I would think that when the ambient temperature goes down, there would be a larger temperature differential making it so that heat from the teensy gets taken away faster than when itās hotter outside. This makes sense in my head, but Iām sure there is something wrong with my reasoning. The name science may be in my degree, but that doesnāt mean Iām any good at it.
If the ground plane is part of the issue, then I could redesign the circuit board to isolate the ground from the sensor from the teensy as much as I can, or get rid of the ground plane altogether.
Itās possible that direct sunlight on the enclosure could be causing problems, radiating heat into the enclosure even though the sensor is in shade. This doesnāt make much sense to me since the same enclosure was used to house the original commercial weather station.
If you have any thoughts on why I might be experiencing temperature issues, I would love to hear from you!
## Remotely flashing firmware
Another problem I have had is that it is impossible for me to flash the firmware to the teensy over serial. That means if I have a firmware update for the station, I will have to go up onto the roof, take down the machine, flash it, take it back up to the roof and hope that everything went smoothly.
Iāve looked into ways that I could reflash the teensy using different UARTs other than Serial0, but it seems that the bootloader is on another chip that is hardwired to the USB port.
I feel like the best option would be to use a different MCU altogether. I have a Arduino Pro Mini laying around which doesnāt have any onboard FTDI chip. I think that I would be able have the chip go into bootloader mode and flash it all through the existing RS422 interface.
āāāāāāāāāāāāāāāāāāāāāāāāāāāāāāāāāāāāāāāā
Iāve been thinking that with the temperature issue and inability to update the firmware, my next step in the weather station project would be to replace the Cortex M7 processor with an Atmel328P chip. It has a much slower clock speed of 16MHz and a much lower power consumption.
Iāve estimated that the teensy draws 90mA (0.3W) and the Arduino draws 6mA (0.02W). Some rudimentary calculations show that 0.02WH of power in a chip should yield about 5ĀŗC of temperature change and 0.3WH of power in a chip should yield about 75ĀŗC of temperature change. These are very rough calculations, but I think it shows that the teensy could very well be affecting the temperature readings and that an Arduino Pro Mini should have a much small impact on the temperature.
=> https://www.omnicalculator.com/physics/watts-to-heat Site where I calculated temperature changes
Iāve already started working on transferring the logic from the teensy to the Arduino. It really shouldnāt be difficult. The most difficult thing will probably be converting from interrupts to PCINT.
]]></content>
<category term="projects" label="Projects" scheme="gemini://benjaminja.com/tags/projects/" />
<category term="weather-station" label="Weather-Station" scheme="gemini://benjaminja.com/tags/weather-station/" />
<published>2024-05-16T17:55:36Z</published></entry>
<entry>
<title><![CDATA[If You Give a Hobbyist a Harddrive]]></title>
<link rel="alternate" type="text/gemini" hreflang="" href="gemini://benjaminja.com/log/2024/01/16-upgrading_server/" />
<id>gemini://benjaminja.com/log/2024/01/16-upgrading_server/</id>
<updated>2024-01-16T07:31:00Z</updated>
<summary type="gemini"><![CDATA[I recently bought a 2TB hard drive for my home server. I use this server to host NextCloud and you can never have enough storage space. This server is an Inspiron 560s from 2008. It only has two hard drive bays and already has two hard drives.
]]></summary><content type="gemini"><![CDATA[I recently bought a 2TB hard drive for my home server. I use this server to host NextCloud and you can never have enough storage space.
This server is an Inspiron 560s from 2008. It only has two hard drive bays and already has two hard drives. There is however a dvd bay and a SD-card bay. The new hard drive fits just perfectly in the SD-card bay, so thatās its new home.
=> /log/2024/01/16-upgrading_server/drive_door.jpg š¼ Hard Drive Door
### The hobbyist will need to try out a new file system
A few months back, I watched a video about ZFS and was convinced to give it a try. The only problem is that it is pretty daunting to even think about trying out.
> There must be so much extra stuff that needs to be learned just to access the file system. Since ZFS is designed to work with other drives, will every drive be required to use ZFS?
These fears are not founded though. It is true that there is some extra software that is required in order to manage ZFS, but it is honestly so much easier than having to deal with parted, or fstab. All I needed to do to format and setup the new disk under ZFS was
zpool create MyPool sda
For me, the strongest selling point of ZFS is that it makes storage work closer to RAM. When running a program, I donāt need to specify which ram stick I want to have my software run in. It just figures it out for me. ZFS has this idea of pools where each pool is made up of one or more hard drives. When I put a file in the file pool, I donāt know which hard drive the data is going into, just that it is being taken care of for me.
I migrated a second 1TB drive in the server to ZFS and added it to my main pool. So instead of having 3 drives to manage, I have the boot drive, and a 3TB storage space.
### While theyāre at it, the hobbyist might as well upgrade the OS
I havenāt updated the OS since I originally setup the machine in 2018. Iām running Ubuntu 18.04 and it has recently gone out of long term support. There are still 4 years left of security maintenance, but I figure since Iām working on the machine now, I might as well upgrade to a newer OS. I would like to try out Debian 12.
I backed up the main drive to my newly created pool and got ready to upgrade the OS. Thereās nothing like some spring cleaning where you can get rid of the residue from all your weird decisions you made in the past 6 years and start fresh.
Creating the installation medium was my first hurdle. For whatever reason, I always have trouble creating an USB installer. I primarily use Mac as my daily driver and Iāve pretty much always relied on the Raspberry Pi Imager for Mac. With newer updates to the software, it feels like it is a lot harder to burn a USB stick with anything that isnāt Raspbian. So I switched over to my windows machine and I went through several programs trying to find one that will actually burn an ISO and make the drive bootable. I settled for Rufus.
I donāt know why, but no matter what I have tried I just canāt get the BIOS to recognize my USB. The machine is old enough that it doesnāt know what UEFI is, but the one time I was able to get the machine to recognize the drive was when it was formatted with GPT which should be UEFI only. I have spent hours making tweaks and re-imaging that poor USB stick to no avail.
### The hobbyist is ready to sleep now
At this point, it might be better to just give up for now. Itās not necessary that I upgrade the OS (In fact I foresee that it would cause more heartache trying to get everything up and running again from a fresh start). There are still several years left of support for the current OS and I got everything done that I was originally intending to do.
Iām really happy with how ZFS has turned out and I should just see how it goes moving forward. The next thing to figure out is how to get docker volumes to live in my pool. But thatās a problem for another day.
]]></content>
<category term="projects" label="Projects" scheme="gemini://benjaminja.com/tags/projects/" />
<published>2024-01-16T07:31:00Z</published></entry>
<entry>
<title><![CDATA[Rewriting my Site Generator]]></title>
<link rel="alternate" type="text/gemini" hreflang="" href="gemini://benjaminja.com/log/2024/01/13-rewriting_site_gen/" />
<id>gemini://benjaminja.com/log/2024/01/13-rewriting_site_gen/</id>
<updated>2024-01-13T21:30:00Z</updated>
<summary type="gemini"><![CDATA[Itās a new year and a new me. Now that I have finally graduated, I feel that I have more time to work on my side projects. One of the first big things I have done is rewriting my site generator once again.
]]></summary><content type="gemini"><![CDATA[Itās a new year and a new me. Now that I have finally graduated, I feel that I have more time to work on my side projects. One of the first big things I have done is rewriting my site generator once again.
=> gemini://benjaminja.info/log/2023/09/03-simple_site_gen/ Simple Site Generator
Rather than creating my own templating engine, I decided to use [tera].
=> https://keats.github.io/tera/docs/ tera
Keeping similar vibes to my original site generator: any additional features is implemented through shell scripts. There are a few important features baked in with the generator and all of the very site specific features are python scripts I created.
It is inspired by [kiln]
=> https://kiln.adnano.co kiln
> ~~but from all of my research it seems that the site has gone down as well as the repo that was holding it.~~
> Update 2024-01-16:
> It turns out that source hut was hit by a DDoS attack and kiln was part of the cross-fire. Everything seems to be back up now.
## Configuration
Here is a copy of my configuration file for https.
"proc/pretty-url.py",
"proc/tags.py", # tags script creates the tag system for my log"proc/pretty-url.py",
]
"proc/proc_html.py",
]
md = { ext = "html", cmd = ["gmi-conv", "-i", "md", "-o", "html"] }
gmi = { ext = "html", cmd = ["gmi-conv", "-i", "gmi", "-o", "html"] }
As an example of what a file might go through, I will show you how this file gets rendered. Letās say that I have the text
{% raw -%}
The site was rendered at {{ now | ftime(fmt="%B %e, %Y @ %r %:z") }}
{%- endraw %}
Here is the output:
> The site was rendered at {{ now | ftime(fmt="%B %e, %Y @ %r %:z") }}
First, the `pretty-url.py` script will be run which renames this file from `content/log/2024/01/13-rewriting_site_gen.md` to `content/log/2024/01/13-rewriting_site_gen/index.md`. After that the `tags.py` script will be run which adds this file to the `capsule` and `projects` tags. The `pretty-url.py` script gets run again for any generated files, then the rendering starts.
Since this is an `md` file, it will get rendered. After being rendered it will be converted to html using `gmi-conv -i md -o html`. (There is another configuration rendering to gemini). After it is converted, the file will be passed through several templates. To be specific:
1. `templates/logs/2024/_root.html` which adds the title, date, and mentions.
2. `templates/_root.html` which adds the base html boilerplate.
Weāre not done yet, finally the `proc_html.py` script gets run. This will use beautiful soup to find any code blocks and adds formatting to it as well as differentiates gemini links as gemini links.
āāāāāāāāāāāāāāāāāāāāāāāāāāāāāāāāāāāāāāāā
I have two configurations running. One for html and one for gemini. I only need to write my capsule once and it will be rendered to both endpoints which is pretty nice.
## Making this Publicly Available
There are still a few oddities about the software that Iām not very happy with. I also want to add a bunch of documentation so that you can actually know how to use it. So I wonāt be releasing my site generator until it is in better shape.
This software is probably a bit into the āYou need to be a computer wiz to use this softwareā territory, but If I were to add some sane 3rd party scripts and some good tutorials, I think it might could be usable by an average person.
]]></content>
<category term="capsule" label="Capsule" scheme="gemini://benjaminja.com/tags/capsule/" />
<category term="projects" label="Projects" scheme="gemini://benjaminja.com/tags/projects/" />
<published>2024-01-13T21:30:00Z</published></entry>
<entry>
<title><![CDATA[Simple Site Generator]]></title>
<link rel="alternate" type="text/gemini" hreflang="" href="gemini://benjaminja.com/log/2023/09/03-simple_site_gen/" />
<id>gemini://benjaminja.com/log/2023/09/03-simple_site_gen/</id>
<updated>2023-09-03T08:06:00Z</updated>
<summary type="gemini"><![CDATA[Itās been a while since I last posted. I have been busy working on my weatherstation. Iāll need to write about that soon, but for now I want to talk about the state of my capsule.
]]></summary><content type="gemini"><![CDATA[Itās been a while since I last posted. I have been busy working on my weatherstation. Iāll need to write about that soon, but for now I want to talk about the state of my capsule.
During my breaks from the weatherstation, I have been working on my own site generator. I have finally got it to the point where I can start using it in production. Thereās definitely a lot of work left to be done before I can publish it for others to use.
I have been calling it `simple-site` for now, though Iāll probably think of a better name when I actually release it. I have designed the generator to be as simple possible while allowing for complexity to come if desired.
The design starts out with templating. I designed my own simple templating engine that I found works surprisingly well. Each document will be rendered and passed to a chain of configured templates. To get added functionality, scripts can be created which will behave like functions in the templating engine. If you need more control, then generator scripts can be used to make alterations to the structure of the site.
Since I have migrated my capsule over to the new system, I have most likely missed a few things.
### Example
Here is a pretty simple example of what my generator does. Hopefully it can help visualize whatās going on.
+- content
| +- index.gmi
| +- my-image.jpg
+- templates
| +- base.gmi
+- site.toml
$ simple-site site.toml
Rendering "index.gmi" with template "base.gmi"Copying "my-image.jpg"
]]></content>
<category term="projects" label="Projects" scheme="gemini://benjaminja.com/tags/projects/" />
<category term="capsule" label="Capsule" scheme="gemini://benjaminja.com/tags/capsule/" />
<category term="gemini" label="Gemini" scheme="gemini://benjaminja.com/tags/gemini/" />
<published>2023-09-03T08:06:00Z</published></entry>
<entry>
<title><![CDATA[Installing Ethernet]]></title>
<link rel="alternate" type="text/gemini" hreflang="" href="gemini://benjaminja.com/log/2023/06/26-upgrading_internet/" />
<id>gemini://benjaminja.com/log/2023/06/26-upgrading_internet/</id>
<updated>2023-06-26T18:52:00Z</updated>
<summary type="gemini"><![CDATA[My house used to be connected to Comcast before we switched over to a local fiber ISP. This switch has happened years ago and the house was outfitted with coax back in the Comcast days. Of course now, there is no use for Coax.
]]></summary><content type="gemini"><![CDATA[My house used to be connected to Comcast before we switched over to a local fiber ISP. This switch has happened years ago and the house was outfitted with coax back in the Comcast days. Of course now, there is no use for Coax. The local antenna stations are not great and we donāt have cable coming in either. So I figured that I would replace our existing coax with ethernet.
We have three coax ports. One in the basement that goes outside along the wall. And two in the house that share the same wall across two floors. The basement port was very easy to replace as I just had to poke the ethernet out the wall and re-enter into the boiler roomāwhere the networking is located.
Iām still planning out how to replace the two remaining ports. My original plan was to attach the existing coax cable to the ethernet cable and pull it through the wall up into the attic without having to cut any access holes. This would work great in theory, but I have found that there is only one coax cable coming into the attic. This means that somewhere in the wall is a coax splitter.
=> /log/2023/06/26-upgrading_internet/example.png š¼ It might be easier to see an example of what I mean.
Iām not entirely certain that this is how the cable was installed, but it seems that way. There are two possible solutions that I can think of to make this work: Make the existing access point hole bigger in the attic so that I can pull the splitter through and not have to cut the walls. I could remove the box on the second floor and remove the splitter from that access point and replace the box in the future.
If I were to cut in the attic, it is possible that I will reduce structural integrity. If I were to remove the outlet box, I may have to make repairs to the wall. The box may not be attached to any studs, free floating on the drywall with mounting ears. This might make it easier for me to remove the box without damaging the wall.
When I get the chance, Iāll try to remove that box and see if Iām right about the splitter.
## Update - Retrofitting telephone wire
2023-06-28
alextheuxguy responded and said that he was lucky that the phone jacks were wired with Cat5e. Thatās pretty cool! And now that I think of it, when I was last in the attic I saw some mysterious 8-wire unsheathed cable up there that looked suspiciously like ethernet. I know there is a telephone jack in the dining room, so maybe I would also be able to retrofit the telephone jack with ethernet.
Iāll have some more investigating to do.
Thanks for the tip Alex!
]]></content>
<category term="home-improvement" label="Home-Improvement" scheme="gemini://benjaminja.com/tags/home-improvement/" />
<published>2023-06-26T18:52:00Z</published></entry>
<entry>
<title><![CDATA[Communicating with my weatherstation]]></title>
<link rel="alternate" type="text/gemini" hreflang="" href="gemini://benjaminja.com/log/2023/06/24-comms_with_weatherstation/" />
<id>gemini://benjaminja.com/log/2023/06/24-comms_with_weatherstation/</id>
<updated>2023-06-24T18:42:00Z</updated>
<summary type="gemini"><![CDATA[In my original plan for my weatherstation, I would wirelessly send weatherdata to a ground station. I have given up on this idea primarily because managing a rechargeable battery would introduce too many variables. Now, I have decided to have a cable that connects between the ground station and the sensors.
]]></summary><content type="gemini"><![CDATA[In my original plan for my weatherstation, I would wirelessly send weatherdata to a ground station. I have given up on this idea primarily because managing a rechargeable battery would introduce too many variables.
Now, I have decided to have a cable that connects between the ground station and the sensors. I will be using an ethernet cable as the medium, but I wonāt be using the ethernet protocol. Having a network card on the station is more overhead than I would like.
The original plan was to connect the serial lines directly. This is not a great idea, since plain datalines cannot go a long distance without losing integrity. Instead, making the lines differential twisted pairsāwhich ethernet is already made ofāwould allow for longer reliable distance. I just donāt know how I would convert a line into a twisted differential pair.
I discovered that CAN bus could be the better option for me. It stands for Controller Area Network, and is designed to be a light weight alternative to Ethernet. CAN is generally used in cars and in industrial settings.
Now I just need to come up with a protocol to manage the weatherstation. Iāve discovered a protocol called CANopen which seems very interesting. Iām currently stuck trying to decide whether I want to fully implement CANopen, or if I want to develop my own protocol that is inspired from CANopen. There is a lot of stuff that goes on with CANopen that I donāt necessarily need (particularly since I donāt plan to integrate the weatherstation with other CANopen devices).
There is a library for CANopen called CANopenNode, however I would have to make my own compatibility layer with it since no has done that for the Teensy4.0. It might just be better for me to design my own partial CANopen library.
Maybe Iāve gone too far into CAN, and would have been better off just using an Ethernet card. Iāve had fun working with CAN and CANopen, so I donāt think I have wasted my own time here, but sometimes I wonder if it would have been better to use a different board that has ethernet built-in.
]]></content>
<category term="side-project" label="Side-Project" scheme="gemini://benjaminja.com/tags/side-project/" />
<category term="weather-station" label="Weather-Station" scheme="gemini://benjaminja.com/tags/weather-station/" />
<published>2023-06-24T18:42:00Z</published></entry>
<entry>
<title><![CDATA[My weather vane is now better than new]]></title>
<link rel="alternate" type="text/gemini" hreflang="" href="gemini://benjaminja.com/log/2023/04/30-repaired_weather_vane/" />
<id>gemini://benjaminja.com/log/2023/04/30-repaired_weather_vane/</id>
<updated>2023-04-30T17:12:00Z</updated>
<summary type="gemini"><![CDATA[Yesterday, I wrote about how I broke and repaird my weather-vane After it got repaired, I was able to get the sensor working in software. Everything worked, but there was one thing odd about the sensor.
]]></summary><content type="gemini"><![CDATA[=> /log/2023/04/29-broke_weather_vane/ Yesterday, I wrote about how I broke and repaird my weather-vane
After it got repaired, I was able to get the sensor working in software. Everything worked, but there was one thing odd about the sensor.
To give some background, the sensor can tell the direction of the wind by triggering one of 8 magnetic reed switches each connected to a resistor. If I measure the resistance of the sensor, I can tell which direction the wind is blowing.
The east resistor measured infinite ohms. In hindsight this is obviously a problem, but I thought that everything was normal until after I did my repair. Why would there be a reed switch that connects to an infinite resistor? This is the same as having a switch connected to nothing.
I took apart the sensor once again to look for any damage. I was only hoping that I wouldnāt have a busted reed switch. After some continuity testing, I found this on the east sensor:
=> /log/2023/04/30-repaired_weather_vane/broken_reed.jpg š¼ A reed switch that has been pulled off the circuit board
This must be something that has been broken for over 6 years now. I was able to make the repair, luckily it was pretty simple. Just a jumper from the resistor to the reed switch.
=> /log/2023/04/30-repaired_weather_vane/repaired_reed.jpg š¼ The repaired sensor
I canāt describe just how happy I am about this.
If the wind points between two of the sensors, then it will no longer think the wind has spontaneously pointed east.
]]></content>
<category term="projects" label="Projects" scheme="gemini://benjaminja.com/tags/projects/" />
<category term="weather-station" label="Weather-Station" scheme="gemini://benjaminja.com/tags/weather-station/" />
<published>2023-04-30T17:12:00Z</published></entry>
<entry>
<title><![CDATA[Whoops, I broke my weather vane]]></title>
<link rel="alternate" type="text/gemini" hreflang="" href="gemini://benjaminja.com/log/2023/04/29-broke_weather_vane/" />
<id>gemini://benjaminja.com/log/2023/04/29-broke_weather_vane/</id>
<updated>2023-04-29T17:47:00Z</updated>
<summary type="gemini"><![CDATA[I am working on my weatherstation project now, and Iām going to finish it for real! Yesterday I was opening up the weather-vane to reverse-engineer the board it has and make sure what I already know is correct.
]]></summary><content type="gemini"><![CDATA[I am working on my weatherstation project now, and Iām going to finish it for real! Yesterday I was opening up the weather-vane to reverse-engineer the board it has and make sure what I already know is correct.
I was able to get my picture and put it all back together; there was only one problem. The sensor no longer worked! It turns out that when I took the board out of the housing, I also pulled the cable a bit too hard and broke the connection to the board, whoops.
Fixing the board should be pretty easy, I just have to remove whatās left of the wires, and solder the wires back in. To make sure that the wires donāt fall apart again, I decided to use solid core wires and connect the cable to that.
Everything went pretty well until I accidentally ripped one of the pads off the circuit board, whoops. I am just lucky that the pad I pulled off had a simple connection that I could easily bypass.
I was able to fix the sensor just fine. It looks a little silly, but thatās ok. The one thing that Iām more annoyed at than anything else is that I didnāt need to take apart the sensor. I had already done that around 6 years ago, and uploaded it to my wordpress blog.
=> /log/2017/04/04-weatherstation/ My blog where I analyzed the weather-vane.
=> /log/2023/04/29-broke_weather_vane/sensor-back.jpg š¼ Back of the repaird weather-vane
=> /log/2023/04/29-broke_weather_vane/sensor-front.jpg š¼ Front of the repaird weather-vane
]]></content>
<category term="projects" label="Projects" scheme="gemini://benjaminja.com/tags/projects/" />
<category term="weather-station" label="Weather-Station" scheme="gemini://benjaminja.com/tags/weather-station/" />
<published>2023-04-29T17:47:00Z</published></entry>
<entry>
<title><![CDATA[Planning PWS Hardware]]></title>
<link rel="alternate" type="text/gemini" hreflang="" href="gemini://benjaminja.com/log/2023/04/16-planning_pws_hardware/" />
<id>gemini://benjaminja.com/log/2023/04/16-planning_pws_hardware/</id>
<updated>2023-04-16T17:26:00Z</updated>
<summary type="gemini"><![CDATA[It has been a dream of mine to create my own personal weather station (PWS). Iāve been working on this project for over 6 years now. Due to school and scope creep: I have not been able to complete this project.
]]></summary><content type="gemini"><![CDATA[It has been a dream of mine to create my own personal weather station (PWS). Iāve been working on this project for over 6 years now. Due to school and scope creep: I have not been able to complete this project. This time will be different. I have a plan. This plan has been split up into two parts: hardware and software. In previous iterations, I have developed hardware and software at the same time without a clear plan, which I believe is part of the reason why it has taken me so long.
With this semester is almost over, I have done a bit of planning so I can hit the ground running with this project. I want to have the hardware installed as soon as reasonably possible so that I can start work on the software remotely.
The general idea for this project is to have a weather station that hosts a web-app. This would allow you to view the current weather conditions from anywhere in the building.
In order to do this, I will have a raspberry pi to host the server and communicate with the station hardware. The station hardware will include a weather vane, rain meter, temperature, humidity, pressure, and possibly a uv-index sensor. This will all be directly controlled by a teensy.
## Hardware plan
The raspberry pi will sit on the roof in a shady spot. It will be connected to the internet via ethernet and get power over ethernet (PoE). The pi will interface with the teensy using CAN over an ethernet cable. Itās possible that the pi could be placed indoors, but I want to attach a camera as a little bonus thing. The teensy will be directly connected with all the sensors over i2c. The weather vane and rain meter donāt have any logic chips and so will need to be specially programmed.
## Software plan
The teensy will generally act as a bridge between the sensors and the pi. The weather vane and rain meter will need special logic which I will go into later. The teensy will respond to requests from the pi. The pi will run OctoWeather (PWS software that I am developing). I havenāt made any plans yet of how this software will work, but I have general ideas of what it will do in my projects page.
The weather vane has two parts: wind direction and wind speed. Both of these use reed switches to detect what is happening. The wind speed closes the circuit on every rotation (maybe every 180Āŗ I canāt quite remember which). The wind direction has eight reed switches each connected to a different resistance to detect which cardinal direction the wind is blowing in. The rain meter has one reed switch that triggers every time 0.01 inches has fallen. The wind speed and rain meter will need to have special software to asynchronously determine how much rain has fallen and how fast the wind is blowing. This should be relatively easy by using pin change interrupts. The wind direction can be connected to a voltage divider to measure resistance on an analog pin.
## What Iāve done so far
I have been able to install an ethernet cable that goes from the basement to the roof. I have also collected all of the hardware that I plan to use for this project.
=> /log/2023/04/16-planning_pws_hardware/ethernet_install.jpg š¼ Ethernet Going to the roof
=> /log/2023/04/16-planning_pws_hardware/pws_hardware.jpg š¼ Hardware I have so far
]]></content>
<category term="projects" label="Projects" scheme="gemini://benjaminja.com/tags/projects/" />
<category term="weather-station" label="Weather-Station" scheme="gemini://benjaminja.com/tags/weather-station/" />
<published>2023-04-16T17:26:00Z</published></entry>
<entry>
<title><![CDATA[Organizing My Life]]></title>
<link rel="alternate" type="text/gemini" hreflang="" href="gemini://benjaminja.com/log/2023/02/26-organizing_my_life/" />
<id>gemini://benjaminja.com/log/2023/02/26-organizing_my_life/</id>
<updated>2023-02-26T21:22:00Z</updated>
<summary type="gemini"><![CDATA[I have always been bad at organizing my life. It can be hard for me to know what to do and when to do it. This is a particularly big problem for me because of executive disfunction.
]]></summary><content type="gemini"><![CDATA[I have always been bad at organizing my life. It can be hard for me to know what to do and when to do it. This is a particularly big problem for me because of executive disfunction. There are many ways in which I could go about keeping track of what needs to be done, but they all boil down to some sort of calendar system. That being said, each system has you think about things in a different way.
I have tried using my calendar app, various todo apps, and physical journaling. Each one has their pros and cons, but they all ultimately failed me in the sense that I have gotten out of the habbit of using them. Life has been getting overwelming recently and so I thought that it would be a good idea to get back into the habbit of using one of these.
It sounds a little odd, but I have found that physical journaling has been the most useful for me. I have a bit of a hard time expressing why this is, but I think it has to do with how a lot of effort needs to be put into writing in a journal. It is so easy to setup an app, that it is also easy to just ignore it. With journaling, what I write tends to sticks with me.
I follow the the bullet journal style of journaling which has been useful for me to have an organized todo list as well as being able to write down my random thoughts.
=> https://help.bulletjournal.com/en-US/articles/bullet-journaling-101-17356 Bullet Journaling 101
Of course, the bulletjournal site will try to sell you a journal or even a course on how to use it. I am just using a notebook a friend gifted to me.
=> /log/2023/02/26-organizing_my_life/journal.jpg š¼ My journal
Iāll eventually fall out of use with my journaling again, but thatās ok because all that matters is that it has been useful while it lasts.
]]></content>
<category term="life" label="Life" scheme="gemini://benjaminja.com/tags/life/" />
<published>2023-02-26T21:22:00Z</published></entry>
<entry>
<title><![CDATA[How I deploy to my server]]></title>
<link rel="alternate" type="text/gemini" hreflang="" href="gemini://benjaminja.com/log/2023/02/13-how_i_deploy/" />
<id>gemini://benjaminja.com/log/2023/02/13-how_i_deploy/</id>
<updated>2023-02-14T17:25:00Z</updated>
<summary type="gemini"><![CDATA[I donāt run this capsule on a server that I physically own. I rent out my server from digitalocean. Since my server doesnāt need to have lots of computing power or memory, I have opted to use the cheapest server possible that pennies can buy.
]]></summary><content type="gemini"><![CDATA[I donāt run this capsule on a server that I physically own. I rent out my server from digitalocean. Since my server doesnāt need to have lots of computing power or memory, I have opted to use the cheapest server possible that pennies can buy. The only problem is that the server is so underpowered: it is nearly impossible to install software from source. In this log, I will explain how I go about deploying software to my server.
=> https://digitalocean.com digitalocean.com
Iāve deployed my server as a droplet using a single shared CPU with 512 MB of memory. Because of these low specs, I have decided that all of my server/CGI software will run on native binaries to make using my capsule as smooth as possible.
The main server software that I use is made with Rust; a language known for its long and intensive compilations. I tried building it on my server and it took around 10 minutes before the build crashed from a lack of available memory. I would probably be better off cross compiling from my computer and uploading the binary than trying to find some workaround.
## Uploading to the server
Compiling software for the server can vary widely from language to language, but it is almost always the same to upload your built binary to the server. The way I do it is by having a `deploy.sh` script in the root of a project that will build, upload, and install the software on the server.
BINARY=path/to/binary
REMOTE=root@my_server
BINAME="$(basename "$BINARY")"BINDIR=/usr/local/bin
TMPDIR=/var/tmp
install -Dm755 ./$BINAME$BINDIR/$BINAME &&
rm ./$BINAME"
Of course depending on the type of software Iām deploying, the script may need to change to fit the projectās needs. I feel that it would be simpler to just scp the binary directly into the installed destination rather than installing it with a separate command, but I kind of like it. ## Deploying Rust Rust has become my goto language when it comes to compiled software. It supports a lot of language features that I like. It can feel like a high-level language while still allowing for low level control. My problem with Rust is with how difficult it is to cross compile. In theory, it is very easy to cross compile Rust, but when external libraries are used: the process becomes infinitely more complicated. You will first need to install a target for your toolchain (This is fairly easy). If the program doesnāt use any external libraries, you should be good to go. Otherwise, you will need to install a C cross compiling toolchain (This can be tricky depending on your host system) and tell rust the linker you will be using in `.cargo/config.toml`. If your build still fails, a library might be compiling C from source, so you will need to tell rust that any C code should be built using your cross compiling toolchain in an environment variable. If you still canāt cross compile the software, then get ready for a never ending rabbit hole. There is a tool that will help you do cross compiling that I wish I had known about before I spent a week learning how to do it manually. It is called āCrossā, and allows you to do cross compilations with very little hassle. => https://github.com/cross-rs/cross Cross You will need to have Docker installed for Cross to work, but I think I have read that it might be possible to configure Cross to use Zig as a linker/compiler instead of building inside a Docker container. Building with Cross is usually as simple as replacing `cargo` with `cross`. Depending on your needs, you may need to create a `Cross.toml` to customize your build, but that is still simpler than doing it manually.
TARGET=x86_64-unknown-linux-gnu
BINAME=<binary>
BINARY=target/release/$TARGET/$BINAME
cross build --release --target $TARGET
## Deploying Go In comparison to Rust, Go is a walk in the park. All that is needed to cross compile Go is two environment variables: `GOOS` and `GOARCH`. I donāt know if there are any edge cases that might show up when building. I really should learn Go.
BINAME=<binary>
BINARY=$BINAME
GOOS=linux GOARCH=amd64 go build
I havenāt needed to do anything else for Go to work, but I also donāt know the language. If it were possible to use external libraries, then I would imagine that cross compilation could get more complicated, but I just donāt know enough about the language to know if thatās even possible. ## Deploying my capsule This isnāt a language, but I figure itās worth mentioning. When I deploy my capsule, I upload the project up to the server and then render it. This allows for semi-dynamic content that is stored exclusively on the server to be rendered into the capsule. The way I go about deploying the capsule is a little bit funky, but it works and thatās all that matters.
DIR="$(dirname -- "${BASH_SOURCE[0]}")"SERVER='gemini@my_server'DEST='/path/to/capsule/data/'SOURCE="$DIR/."GEMINI="/var/www/gemini/my.site/"COMMAND="${1:-upload}"# Upload to the serverif["$COMMAND"="upload"]; then# Synchronize the project with the server rsync -rltp --delete-after -z --exclude='./git' --filter=':- .gitignore' -h "$SOURCE""$SERVER:$DEST" echo "Uploaded capsule"# Run the build section of the deploy script on the server ssh -t "$SERVER""cd $DEST ; ./deploy.sh build"elif["$COMMAND"="build"]; then# Render the capsule cd "$DIR" kiln build
RES=$?
if[ $RES -ne 0]; then exit $RES
fi# Copy the rendered files into the server folder rsync -r "${DEST}public/""$GEMINI" RES=$?
if[ $RES -ne 0]; then exit $RES
fielse echo "Invalid Command, should be one of [upload, build]"fi
I havenāt yet had the chance to deploy any other types of software, but I can imagine that some will be easier than others. Zig should be pretty simple, but C/C++ scares me. The thought of having to find or build libraries does not seem at all fun. Though C/C++ should still be easier than Rust.
]]></content>
<category term="projects" label="Projects" scheme="gemini://benjaminja.com/tags/projects/" />
<category term="capsule" label="Capsule" scheme="gemini://benjaminja.com/tags/capsule/" />
<category term="gemini" label="Gemini" scheme="gemini://benjaminja.com/tags/gemini/" />
<published>2023-02-14T17:25:00Z</published></entry>
<entry>
<title><![CDATA[My Capsule Plans]]></title>
<link rel="alternate" type="text/gemini" hreflang="" href="gemini://benjaminja.com/log/2023/02/10-capsule_plans/" />
<id>gemini://benjaminja.com/log/2023/02/10-capsule_plans/</id>
<updated>2023-02-10T19:20:00Z</updated>
<summary type="gemini"><![CDATA[I have been getting fairly ambitious with ideas for my capsule. This is dangerous with me being in the middle of a heavy semester, so I am going to write down my plans and implement them later.
]]></summary><content type="gemini"><![CDATA[I have been getting fairly ambitious with ideas for my capsule. This is dangerous with me being in the middle of a heavy semester, so I am going to write down my plans and implement them later. Hopefully I donāt end up working on these projects to avoid my schoolwork (I am writing this very log to distract myself from a project I need to do š).
## Serve my content on both gemini and https
At the moment, I am serving my capsule on the www under a proxy. This has been good, but I would like to have more control of how it looks. To do this, I want to serve my capsule natively on both gemini and https protocols.
I want the feel of the web version to be simple, but feel like it was meant for the web. Primarily so that I can have a navigation section and inline images.
If I were to do this, I might need to write most of my content in markdown so that I can convert it into http/gemtext without much fuss.
## Automated Gemmentions implementation
=> https://codeberg.org/bacardi55/gemini-mentions-rfc Gemini Mentions RFC
Seeing some of the implementations of gemini mentions has been really good. Notably Seanās implementation where mentions to a post are placed at the bottom of the page under āDiscussions about this entryā. I particularly like how it feels like Iām going through a big discussion thread without the need of looking through an aggregator.
=> gemini://gemini.conman.org/boston/2023/01/04.1 Thoughts on an implementation of Gemini mentions (The post where I first saw mentions being used)
I want to have a feature like this myself, but I also donāt want to do any of it by hand. The idea would be to have a gemmention CGI script that adds mentioned pages to a database, then ask the site generator to rebuild the capsule (Any mentions would be placed in a footing after the article).
Iāve already written a CGI program that can upload mentions to a database, but I have yet to figure out how to insert mentions into posts. I would like to make the program portable so that anyone who would like to have similar functionality could do it themselves. The only problem is that the software I wrote is too complicated to publish without a lot of simplifications.
## Aggregate topics
On most of my pages, I have added a little topics section at the top of the page. I want to have a section of my capsule where you can sort by similar topics.
I would have tags stored in the frontmatter and my site generator could generate pages for each topic. Also the title, date, and tags could be automatically inserted into the generated gemini files so I donāt have to repeat myself too much.
An example of the frontmatter might be like:
---
title: My Capsule Plans
date: 2023-02-10T12:20:00-07:00
tags:
- plans
- capsule
author: ttocsneb
---
I have been getting fairly ambitious with ideas for my capsule...
## Learn the ins and outs of Kiln
=> gemini://kiln.adnano.co/ Kiln
I am currently using Kiln to build my capsule. It has been great so far, but there are a few features that confuse me. I think that most of my problems lie in the fact that I am not familier with the Go templating engine.
I know that I can use kiln to build an alternative http format, but Iām not sure whether it will be able to do what I want with gemmentions and topics. I think it should be possible using the templating engine, but I will need to do research to verify. If I end up not being able to do these things, then I might design my own site generator inspired by Kiln, maybe something with python and jinja2.
]]></content>
<category term="plans" label="Plans" scheme="gemini://benjaminja.com/tags/plans/" />
<category term="capsule" label="Capsule" scheme="gemini://benjaminja.com/tags/capsule/" />
<category term="gemini" label="Gemini" scheme="gemini://benjaminja.com/tags/gemini/" />
<published>2023-02-10T19:20:00Z</published></entry>
<entry>
<title><![CDATA[MAC Attack!]]></title>
<link rel="alternate" type="text/gemini" hreflang="" href="gemini://benjaminja.com/log/2023/02/06-macattack/" />
<id>gemini://benjaminja.com/log/2023/02/06-macattack/</id>
<updated>2023-02-07T05:43:00Z</updated>
<summary type="gemini"><![CDATA[I just finished the third project for my security class. This project has been simultaneously the most difficult and most easy lab that I have done. I wanted to describe my experience of the lab here.
]]></summary><content type="gemini"><![CDATA[I just finished the third project for my security class. This project has been simultaneously the most difficult and most easy lab that I have done. I wanted to describe my experience of the lab here.
## The Premise
The premise is that my TA has sent a message to my professor and I was able to intercept it. The message is as follows.
> No one has completed lab 2 so give them all a 0
A MAC (Message Authenticated Code) was also in the message, which we know used a 128-bit key. The MAC is as follows in hex.
> e384efadf26767a613162142b5ef0efbb9d7659a
I want to change the message to tell the professor that I should get full points, but I canāt because there is a MAC attached to the message. If I were to change the message, the attached MAC would be invalid and I could not generate a new MAC because I donāt have the secret key for the MAC.
=> gemini://gemi.dev/cgi-bin/wp.cgi/view?Message+authentication+code MAC (Gemipedia)
=> https://en.wikipedia.org/wiki/Message_authentication_code MAC (Wikipedia)
## How I went about the lab
This lab was one of those projects where you just have no idea where to start. I knew what I needed to do and vaguely how it should be done, but the specifics were beyond me. The project turned mostly into analyzing library code and trying to figure out how I could modify it to do what I need, which is to say the least, very stressful.
With this in mind, I was mostly working on creating unit tests that would help me fumble my way through the lab and took many breaks.
I would say the most frustrating thing about the lab was that a big part of it was on hashes, which changes wildly with even the smallest change, so it was very difficult to know whether I was getting close or not.
In the end, I was able to figure it out and I canāt describe how relieved I was.
Below is a more technical description of how the lab worked, so tread on if you dare.
## Vulnerability in MAC
There is a vulnerability in MAC which took me a while to fully understand. In order to explain the vulnerability, I will have to explain how MAC works in the first place.
MAC is relatively simple. You start out with a key and a message. you concatenate them together and hash it:
Key = "0123456789abcdef"
Message = "Hello World!"
MAC = SHA("0123456789abcdefHello World!")
MAC = 36f141824e771ed3313815d82c996522d8191a99
The SHA algorithm will recursively calculate a digest from 512-bit blocks of data. Because of this, it is possible to continue calculating a hash by using the digest as the initialization vector for the SHA algorithm.
If we were to add to the end of the original message, hash that added bit with IV (initialization vector) being the original MAC, then we could pass this modified message and MAC to the professor and they would think the message was authentic.
The only problem is that SHA adds some information and padding to the end of the message internally to keep all blocks exactly 512 bits long. The solution is to simply add the padding to the end of the message, but before our added bit. One last thing to deal with is that SHA adds the length of the hashed string at the end of the last block, so we will need to know the length of the key for this to work.
## The Attack
We are given pretty much everything we need for the attack. The most difficult thing will be figuring out how to modify the IV. According to my teacher, golangās API for SHA allows setting the IV, but most languages donāt provide that functionality. I had to download a SHA-1 library and modify it myself to allow for setting an initialization vector. Analyzing the library and making it work for what I need was probably one of the most hair pulling things I have done.
Adding the padding to the message wasnāt too difficult, particularly with the aid of unit testing.
In the end I was able to generate this message to send to my teacher; posing as my TA with a valid MAC. The message itself looks a little corrupted, but that is a problem to deal with another day.
> Message: No one has completed lab 2 so give them all a 0\x80\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\xf8P.S. Except for ttocsneb, Give him 100%
> MAC: d338d12365cd75f5f13673991d9cd1359e355b2e
## Prevention from this kind of attack
The best way to prevent this attack from being possible would be to use HMAC instead. It essentially performs two hashes with the key being manipulated in a way that I can not understand.
=> gemini://gemi.dev/cgi-bin/wp.cgi/view?HMAC HMAC (Gemipedia)
=> https://en.wikipedia.org/wiki/HMAC HMAC (Wikipedia)
]]></content>
<category term="school" label="School" scheme="gemini://benjaminja.com/tags/school/" />
<category term="projects" label="Projects" scheme="gemini://benjaminja.com/tags/projects/" />
<published>2023-02-07T05:43:00Z</published></entry>
<entry>
<title><![CDATA[School has begun]]></title>
<link rel="alternate" type="text/gemini" hreflang="" href="gemini://benjaminja.com/log/2023/01/15-school_has_begun/" />
<id>gemini://benjaminja.com/log/2023/01/15-school_has_begun/</id>
<updated>2023-01-15T17:06:00Z</updated>
<summary type="gemini"><![CDATA[I find it funny that I chose to start a gemlog right as school started. I was fully expecting to be able to put out more content than I have so far, but thatās ok. School should probably have a higher priority than my hobbies.
]]></summary><content type="gemini"><![CDATA[I find it funny that I chose to start a gemlog right as school started. I was fully expecting to be able to put out more content than I have so far, but thatās ok. School should probably have a higher priority than my hobbies.
Iām almost done with school! Iāll be taking my final CS classes this semester with a few generals. For spring and summer terms, I just need to take 3 GEs and I will be graduated! The first week has already passed, so I have a pretty good idea of how this semester will go. I will be taking these classes this semester:
//wait for an available packet
time_point t = Clock::now();
while(!successfull && timeDiff(t, Clock::now()) < eeprom::listenTime) {
sleep_for(500ms);
successfull = checkForPacket();
count++;
}
//If we are desyncing, compensate.
count -= (eeprom::listenTime /500) /2;
if(count !=0) {
reloadTime += (count *500);
cout <<"Desynced by "<< count *500<<"ms, adjusting"<< endl;
}
Every time the weather station successfully sends a packet: the program will process the data. Upload the weather. And send any commands.Ā Since I have a website to check the current weather/station status;Ā I need to have some way of getting that data to the website.Ā So I decided to use MySQL for data storage and transfer.
MySQL
I am not very skilled in MySQL; after all, Iāve only just learned it.Ā My plan for the database is to hold the weather for 24 hours to display on the website and to move information from one program to another without the hassle of parsing individual files.Ā Here are the tables I have made, displayed in a table.
Website
The website Iām making is designed to be for me only: to get information about the station without SSHing into the baseStation.Ā If I wanted to get the weather, I would use Weather Underground.Ā Also, I donāt think a Raspberry Pi Zero is equipped to handle more traffic than my immediate family.
The website is fairly straightforward, Iām using the [SB Admin] Bootstrap template.Ā A few pages: One displaying the status, and other useful information.Ā Another with the current weather with a 24-hour graph of previous temperatures, pressure, humidity, rain, and wind.Ā Iām using PHP to connect to the MySQL database to get the weather/status information.
=> https://startbootstrap.com/template-overviews/sb-admin/ SB Admin
In the future, I want to have a page for configuring the weather station from the website.Ā Such as setting EEPROM variables on the weatherStation, or resetting the system remotely.Ā One worry I have is permissions.Ā I want the website unable to process these commands unless I am logged in.Ā However I have never done anything like that before, so could be more difficult than I think.Ā Of course, it could also be much easier than I think as well.
## Conclusion
As I continue to work on this project, I want to post once a week, or whenever I work on the weatherStation.Ā That way I could give more detail, and include more code snippets to help anyone who might find this website who is also building their own weather station.Ā I hope to get this project done in the next month;Ā I also was planning to get it done a year ago so donāt expect too much.
]]></content>
<category term="wordpress" label="Wordpress" scheme="gemini://benjaminja.com/tags/wordpress/" />
<category term="weather-station" label="Weather-Station" scheme="gemini://benjaminja.com/tags/weather-station/" />
<published>2018-05-18T18:21:09Z</published></entry>
<entry>
<title><![CDATA[WeatherStation]]></title>
<link rel="alternate" type="text/gemini" hreflang="" href="gemini://benjaminja.com/log/2018/04/09-weatherstation/" />
<id>gemini://benjaminja.com/log/2018/04/09-weatherstation/</id>
<updated>2018-04-09T18:12:09Z</updated>
<summary type="gemini"><![CDATA[šĀ GitHub Repository šĀ WeatherStation Posts This is an ongoing project, see the above links for more information on the project A number of years ago, my father got a home weather station for his birthday.
]]></summary><content type="gemini"><![CDATA[=> https://github.com/ttocsneb/Weather-Station šĀ GitHub Repository
=> /tag/weather-station/ šĀ WeatherStation Posts
> This is an ongoing project, see the above links for more information on the project
A number of years ago, my father got a home weather station for his birthday.Ā It is a simple station that reads wind, rain, temperature, and humidity.Ā It was a good for seeing how much rain we got, or how hot it is at our house.Ā Somewhat recently, it broke, we arenāt sure what happened, but I decided to recycle the parts and create a new, better weather station.
My plan is to make a weather station that uploads its data to [wunderground.com] using their [PWS Upload Protocol]. The problem is that I need to send the weather data through a GET request, which I need a device with wifi.Ā I could use an ArduinoĀ with wifi, but I donāt think that our wifi has a good enough range to use from the roof.Ā So I am using an [RF24L01+] module from the station to a raspberry pi 0 baseĀ station, which will upload the data.
=> https://www.wunderground.com/ wunderground.com
=> http://wiki.wunderground.com/index.php/PWS_-_Upload_Protocol PWS Upload Protocol
=> https://arduino-info.wikispaces.com/Nrf24L01-2.4GHz-HowTo RF24L01+
The idea is simple but has a number of problems that need to be addressed, such as power.Ā I plan to use a Li-ion battery with a solar panel to charge.
### RF24 Protocol
Every 30 seconds, the station will activate the radio, and send the weather data down to the base station, then listen for any commands for the next 2 seconds.Ā This will allow me to make changes to some constants in the station without having to reflash.Ā I should also be able to ask the stationĀ to do things, such as reset.
The commands are single chars followed by whatever else is needed.Ā ie āSā is for setting the value of a constant, followed by a char of the code for the constant to be changed, followed by the value.Ā If the command is a request, the station will send a packet back to the base.
### Solar Power
I am using an Adafruit Feather chip which has a Li-ion charging circuit built-in, so all I need to do is connect a solar panel to the charger.Ā However, I ran into an issue, where when the power drops too low to charge, then rises back, the charging circuit will stop charging as expected, but will not start charging again until the solar panel is disconnected and reconnected.Ā I plan to create a circuit with a mosfetĀ and voltage reader so that the station can deactivate the solar panel when it canāt supply enough current.
]]></content>
<category term="wordpress" label="Wordpress" scheme="gemini://benjaminja.com/tags/wordpress/" />
<category term="weather-station" label="Weather-Station" scheme="gemini://benjaminja.com/tags/weather-station/" />
<published>2018-04-09T18:12:09Z</published></entry>
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