The HR80 radiator controllers and the CM67z controller units communicate via RF in the 868 MHz frequency band.
In Europe, 863 to 870 MHz band has been allocated for license-free operation using FHSS, DSSS, or analog modulation with either a transmission duty cycle of 0.1%, 1% or 10% depending on the band, or Listen Before Talk (LBT) with Adaptive Frequency Agility (AFA). To listen to this communication, a RF module called “RFBee” can be used. It provides easy and flexible wireless data transmission between devices and is based on a AVR Atmega168 (8 MHz internal clock frequency) working as a fully functional Arduino connected via SPI to a TI CC1101 RF transceiver.
- Default firmware can be used to easily implement a point-to-point or point-to-multipoint network.
- If you are free to decide how the frames sent over the air look like (e.g. length indicator or CRCs) then you can use CC1101’s built-in package handling functions.
- If you want to receive RF frames that are not supported by the CC1101’s built-in package handling functions, then you have to write your own customized firmware using Arduino, and you have to dive into the CC1101 specification. However, you can use large parts of the “original” firmware, which is available as source code.
- With a Atmel ATmega 168 clocked with only 8 MHz, you don’t have too much computing power to do complex coding/decoding of frames received over the air.