Wired Sensors

This part of the documentation describes the sensors interface. With sensors we mean devices that are physically connected/attached to the Raspberry  to one of the GPIO pins. So they are connected with a physical wire. Sensors typically are temperature/humidity interfaces or energy sensors.

What makes sensors different from the "normal" receivers: The latter operate asynchronously and begin to send as they like it. The connected wire sensors will only start once they receive a command over the line from the MCU (Micro Controlling Unit aka Raspberry).

For the sake of simplicity, I like to categorize wired sensors in the following groups:

1. Sensors without a bus mechanism, so every sensor might have its own protocol and will be connected to a free GPIO pin.
2. Single- or One-Wire sensors with Dallas bus protocol
3. Two-wire sensors on the I2C bus
4. Energy sensors, connected to the P1 bus of your Smart Meter