IO Expander

With the IO expander pcf8574/5 you can add more GPIO relays and buttons to TerrariumPI. This IO expander does only support on/off actions. So it is not possible to use this IO expander with a DHT sensor. You cannot read out the extra GPIO ports.

PCF8575 Bug

At the moment it is not possible to use a pcf8575 IO expander to add more buttons. Due to a bug in the used library, we can only support relays with this IO expander.

Addressing

In order to use this IO expander, enter the following address in the GPIO relay or button address field.
pcf857[4/5]-<IO expander port>,<I2C Address>,[I2C Bus number]

<IO expander port> is mandatory and is a number from 1 till max ports.

<I2C Address> is mandatory and specified here.