This repo contains the code for an arduino board driving an individually addressable LED strip. It uses the FastLED library to interface with the LEDs. The goal of this project was to have an RGB strip that is both easily controllable from a server (as little hardcoded effects as possible) while still being as fast as possible (server doesn't send every frame). The solution was to make it possible for the server to define the following:
- An effect, this is the highest-level definition
- It contains any number of steps. Each step can indicate how long it runs before the next step is chosen. This can be used to for example create a strobe effect.
- A step contains data about how it moves (direction, move interval), a background color and any number of sequences. These sequences are painted on top of each other. We
- A sequence can be:
- A single color (can be used to layer a rainbow pattern if you combine a bunch)
- A sequence of colors that repeat N number of times
- A randomly colored pixel (can be more than 1 pixel) and the period by which it switches color
- Unpainted pixels
Together this can be used to draw quite a few pretty effects with it all remaining configurable from the server.
This project uses PlatformIO for simple uploading and interfacing with the board itself.
This project is part of the larger home-automation project, where this is part of the RGB module.
As mentioned before, there are a lot of individual modes. The current mode is set, along with a bunch of configuration values for the mode, through the serial module. It then runs until told to stop.
The power module makes sure power consumption does not go above the set amount. A problem with LED strips is that they tend to use quite a bit of power. Around 10 watts per meter. This may not seem like a lot but when you have 15 meters of LED strips it adds up, especially since the cables are not capable of transferring all of the delivered power. Hooking up a regular PSU will still not deliver all of the required power.
The result of insufficient power is LEDs not turning on, turning what is supposed to be white light (R+G+B) into yellowish light. Of course it's better to have a less bright but accurate color than a very bright but washed out color. To achieve this, the power module calculates the power usage of the current paint job and scales accordingly.
Serial control from the server needs to be possible. This becomes a bit complex since the modes and their parameters can be quite numerous. The serial control module exists to parse all incoming data.
Because data is sometimes lost in serial messages (probably having to do with the arduino never waiting and constantly painting), a way of checksumming and acknowledging messages has to be created. It's not necessary for this to be very complicates since messages can just be re-sent. As a result, messages just have the format / message \, where the slashes' presences are checked. If this was correct, the arduino sends back a bunch of "ack" messages to the server.
Copyright 2019 Sander Ronde
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