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A MicroPython (with a little help from JavaScript) implementation of "Musical Stairs" project.
The project relies on WiPy for protocell readings and a RaspberryPi for playing the dedicated sounds and the current version uses only 5 photocell sensors and is limited to 5 tones, namely: A, B, C, D, E.
WiPy + RasPi combo is used as I had a "free" WiPy and a RasPi that was already connected to home stereo. Only thing to solve was porting of Python code for reading the photocell sensors (based on an Adafruit tutorial) to MicroPython and communicating the readings via LAN to RasPi.
Each of the available photocells is cycled through until the light is "lost". Afer that, the app starts counting how long the current cell is without the light source and, when reaching a dedicated threshold (DARK_ACCUMULATED), fires a "play sound" request.
Half-second DELAY after playing a sound ensures a "reasonable" timeout between tones.
As MicroPython (to my knowledge) doesn't have a high level HTTP library/module, a communication on a socket level was needed, but it does the job sufficiently (but w/o any error handling, mind you) of relaying the tone to the dedicated "player" (i.e. RaspberryPi in my case).
The "player" listens on a dedicated route (GET /play/:tone) and uses omxplayer to play the corresponding piano tone from sounds folder.
Currently, as can be seen from read_photo.py, the Python photocell reading "module", these GPIOs are used: GP4, GP0, GP3, GP31, GP30.
Also, one can experiment with different DARK_ACCUMULATED threshold and DELAY between tones.
For connecting to the right "player", the player_address and player_port need to be the same as configured on the "player".
The "player" part is implemented on Node.JS. Not necessary per se, just my preference. Important is to have a listener on some machine capable of playing a sound.
Note the server address (to be used for player_address in read_photo.py) and port defined in app.listen(3030);.
Don't forget to execute npm install once you have cloned the repo.
Log to RasPi and start the "player" with node app.js.
Telnet to WiPy and start reading the photocells with import read_photo; read_photo.read().
To Adafruit for the Python tutorial and to whomever came up with the idea for Musical Stairs triggered by light sensors :)