Managing upto 64 different relay channels using PCF8574 I2c Expander and Raspberry Pi 4.
- i2ctest.py - I2C-Pi communication demo.
- Relay_Test_F.py - OOPS version of main code.
- txr_i2c_relay_drv.py - Relay driver package. modified version of Relay_Test_F.py.
- Relay_Trigger.py - The first iteration of main code.
- Relay_Trigger.py.bak - Backup file, previous iteration.
1 i2c device can manage upto 8 relay pins. This code takes information like number of I2c Devices, their addresses etc. from the user. All the device addresses and Initial values are stored in respective arrays D[] and V[]. Based on the relay control instruction, this code sends appropriate signal to the desired Relay via the I2C IO expander board.
The Relay board is Low Level Trigger type, which means when we send 0 the relay will be ON.
To turn ON a pin &= ~(1<<pin_no) is used and to turn OFF a pin |= (1<<pin_no) is used. Everytime user sends a new command, the previous state of the I2C pins are updated with "AND" or "OR" operations.
