device scripts for PCA9685 dimmers
Posted: Tuesday 15 December 2020 12:00
Hi,
First of all, let me say that I'm a noob at scripting, but eager to learn !
I want to use Raspi with PCA9685 on I2C bus for creating dimmer channels for LED PWM dimming.
I have succeeded in loading the Adafruit library and the test-script for PCA9685 is working.
Now (in my testing environment) I call this script by calling it from "On Action" and "Off Action" in devices, but this is very rudimentary, as it only sets fixed levels (not actually dimming) and also it appears to initialize the I2C bus each time, creating a "dropout" in the PWM causing the lights to flicker each time a script runs ...
So I wonder how to create DEVICE scripts (in Python, because the PCA9685 library is Python) for using these PWM channels as individual dimmer devices ?
I have device (LUA-)scripts for doing this exact thing with ESP-Easy on ESP8266 ...
These scripts read the dimmer levels of the Domoticz devices each time it gets changed and transmit the values to the devices to dim them accordingly ...
Is there a way to "convert" these scripts into Python and tailor them towards the PCA9685 channels ?
(Then I could finally replace my Wifi-dimmers (not really stable) with wired dimmers ... after many years of frustration !)
Can some of you scripting geniusses help a beginning noob with this ?
Forever gratefull,
Pascal
Belgium
First of all, let me say that I'm a noob at scripting, but eager to learn !
I want to use Raspi with PCA9685 on I2C bus for creating dimmer channels for LED PWM dimming.
I have succeeded in loading the Adafruit library and the test-script for PCA9685 is working.
Code: Select all
#!/usr/bin/python3
# This simple test outputs a 50% duty cycle PWM single on the 0th channel. Connect an LED and
# resistor in series to the pin to visualize duty cycle changes and its impact on brightness.
from board import SCL, SDA
import busio
# Import the PCA9685 module.
from adafruit_pca9685 import PCA9685
# Create the I2C bus interface.
i2c_bus = busio.I2C(SCL, SDA)
# Create a simple PCA9685 class instance.
pca = PCA9685(i2c_bus)
# Set the PWM frequency to 60hz.
pca.frequency = 2000
# Set the PWM duty cycle for channel zero to 50%. duty_cycle is 16 bits to match other PWM objects
# but the PCA9685 will only actually give 12 bits of resolution.
pca.channels[15].duty_cycle = 0xFFFFSo I wonder how to create DEVICE scripts (in Python, because the PCA9685 library is Python) for using these PWM channels as individual dimmer devices ?
I have device (LUA-)scripts for doing this exact thing with ESP-Easy on ESP8266 ...
Code: Select all
commandArray = {}
DomDevice = 'Badkamer-tv'
IP = '192.168.20.10'
if devicechanged[DomDevice] then
if(devicechanged[DomDevice]=='Off') then DomValue = 0;
print ("Turning off " .. DomDevice);
runcommand = "curl 'http://" .. IP .. "/led/0/" .. DomValue .. "'";
print (runcommand);
os.execute(runcommand);
return commandArray
else
DomValue = (otherdevices_svalues[DomDevice]);
CalcValue = DomValue * 3.3;
end
print ("Value received from Domoticz was " .. (DomValue) .." ");
print ("Dimming " .. (DomDevice) .. " to " .. (DomValue) .. " ");
runcommand = " curl 'http://" .. IP .. "/led/0/" .. CalcValue .. "'";
print (runcommand);
os.execute(runcommand);
end
return commandArrayIs there a way to "convert" these scripts into Python and tailor them towards the PCA9685 channels ?
(Then I could finally replace my Wifi-dimmers (not really stable) with wired dimmers ... after many years of frustration !)
Can some of you scripting geniusses help a beginning noob with this ?
Forever gratefull,
Pascal
Belgium