💾 Archived View for eoinrul.es › projects › LEDDisplay captured on 2023-12-28 at 15:14:08. Gemini links have been rewritten to link to archived content
⬅️ Previous capture (2022-04-28)
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A remote controlled "on-air" messaging system.
I ended up with a 32x8 pixel LED display from testing the Monome project. I might as well use it, and what use could it be if not to send messages?
Initial test to display a message
First test to write to the display. Next, I hooked this up to an IR sensor, and pre-programmed some messages. This worked nicely, but had the major flaw that the only IR remote control I had was for a stereo I actually use, so changing the message also happened to mess with the stereo. Around this time, I added a button which would display prime numbers - just start at 2 on power-on and calculate the next number after each button press.
I wanted to experiment with MQTT, so the next step was to hook the display up to an ESP8266 and get it on the Internet. Aside from being opinionated about certificates, MQTT is a joy to work with for this kind of thing. It very easily allows for bidirectional communication between the display and a server. Persistence of messages really minimizes the amount of code needed on the microcontroller. A trivial little web app allows me to send arbitrary messages, drawings or prime numbers. In the spirit of being moderately janky, prime calculation is done on the micro, so it should be possible to DOS the micro by asking for a whole ton of primes. I haven't noticed this being a problem.
It's now a pretty fun device. Have to make it look halfway presentable, but there's not a whole lot to the electronics, and the whole point is the display.
A conveniently-sized photo frame
I picked up this picture frame from a charity shop. It's nice and deep and just about the right size for the display.
Making the ESP2866 presentable
I wanted to make the ESP8266 visible, particularly as I could make the whole arrangement thinner, and avoid anything sticking out from the frame. I had some thick, varnished copper wire lying around, so I attempted to use the wire to hold the electronics to each other rigidly and make them look like they're supposed to be there.
Wiring some power around the back and making a background from some leftover wrapping paper gives it that authentic "arts and crafts hour" feeling.
