lexszero / esp8266-pwm

Control PCA9685 PWM driver over WiFi with ESP8266 and NodeMCU

esp8266-pwm

Summary

Code for ESP8266 WiFi module with NodeMcu firmware to control PCA9685 PWM controller. You can easily build WiFi-controlled smart home equipment or toys with this. Also contains a demo application: RGB LED strip with WiFi.

Licensed under WTFPL

Requirements

Hardware

• Any ESP8266 module
• PCA9685 connected to ESP's GPIOs

My hardware (so mad skillz!):

TODO: example schematics, photo/video of actual hardware

Software

• NodeMCU
• esptool for flashing NodeMCU
• luatool for uploading Lua code

PCA9685 driver Lua API

TODO: maybe write something useful here

Read the source

There are also some useful stuff in utils.lua

rgbstrip: demo application

Directory rgbstrip contains an application to control a RGB LED strip over WiFi via MQTT protocol. RGB channels are usually driven with MOSFETs controlled by PWM.

Installation

• Connect ESP8266 to PC (we assume that device is connected to /dev/ttyUSB0)
• Install NodeMCU, if you don't have one:

./esptool/esptool.py --port /dev/ttyUSB0 erase_flash
./esptool/esptool.py --port /dev/ttyUSB0 write_flash 0x0 nodemcu-firmware/pre_build/latest/nodemcu_latest.bin

• Edit rgbstrip/init.lua and change configuration as you wish
• Upload Lua files

for f in pca9685.lua rgbstrip/*.lua; do
    ./luatool/luatool.py -f "$f" -t "`basename $f`" -p /dev/ttyUSB0 || break
done

• Pre-compile pca9685.lua and server.lua on ESP8266. This is needed because NodeMCU sometimes runs out of RAM when loading Lua modules. Open your favorite serial terminal program (warning: init.lua configures UART to 115200 baud, NodeMCU's default is 9600). Run following commands in NodeMCU REPL:

node.compile('pca9685.lua')
node.compile('server.lua')

• If there was a compilation error, you can reset device and try again. Shit happens.
• If compilation was succesfull, there will be created pca9685.lc and server.lc files in NodeMCU filesystem. Now original files can be removed:

file.remove('pca9685.lua')
file.remove('server.lua')

MQTT interface

To control RGB strip, publish a MQTT message with topic <mqtt_topic>/rgb (where <mqtt_topic> is what you set in init.lua) and payload with desired color as hex string (e.g. ff00ff - purple).

rgbstrip.sh: a simple control tool

It uses mosquitto to publish MQTT messages and Xdialog for simple GUI.

• Set your MQTT credentials in mqtt_args variable in the beggining of the script
• Run rgbstrip.sh with one of the following arguments
  • w or white: set total brightness (r=g=b)
  • c or color: set color with regular color choose dialog
  • h or hsvcolor: set color with Hue/Saturation/Value sliders
  • m or midi: read MIDI control events from ALSA and set color accordingly
  • any other value: set color with Red/Green/Blue sliders