The number of GPIO pins on the ESP module can be expanded with a IO Expander. We will use the MCP23017 that provides 16 more pins that can be used as input or output. This way it becomes possible to control a 16 channel relay board.
Each individual pin can be used as either input or output.
The MCP23017 needs to be connected through the I2C interface. This chip is compatible with 3V3 and it can be connected to the ESP without levelshifters..
MCP23017 ESP-01 GND GND VCC VCC SDA GPIO 0 SCL GPIO 2
Configuration depends on how you want to use a certain port on this device. Ports are numbered 1 to 16 (if you have a single MCP23017 connected)
To have an input port act as an input switch device (just like with the default onboard GPIO pins) you need to edit a ESP Easy task and select the "MCP23017 input" device.
You then select the portnumber and additional configuration depending on the controller type. For Domoticz, you enter the IDX that was allocated by Domoticz for this virtual switch.
Portnumbering depends on the I2C address used:
|0||0||0||0x20||1 - 16|
|1||0||0||0x21||17 - 32|
|0||1||0||0x22||33 - 48|
|1||1||0||0x23||49 - 64|
|0||0||1||0x24||65 - 80|
|1||0||1||0x25||81 - 96|
|0||1||1||0x26||97 - 112|
|1||1||1||0x27||113 - 128|
You can control output pins on this chip with the following http command:
http://<ESP IP address>/control?cmd=mcpgpio,<pin>,0
http://<ESP IP address>/control?cmd=mcpgpio,<pin>,1