ESP8266 and MCP23017, DHT22 sensor addition.

[woodsaw]

hi guys,

I need some coding help. I am trying to add DHT22 sensor via a MCP23017 expander, and it doesn't seem to work. here's the code.

i2c:
  sda: GPIO4
  scl: GPIO5

mcp23017:
  - id: mcp23017_hub
    address: 0x27

sensor:
  - platform: dht
    pin:
      mcp23017: mcp23017_hub
      number: 4
    temperature:
      name: Temperature
    humidity:
      name: Humidity
    model: dht22
    update_interval: 300s

If I add it directly to the ESP8266 pins, it works. Here's the code:

sensor:
  - platform: dht
    pin: GPIO12
    temperature:
      name: Temperature
    humidity:
      name: Humidity
    model: dht22
    update_interval: 300s

There are other binary sensors and switches connected to MCP23017 and they work fine. What am I doing wrong?