Here is a little setup to see what’s going on in the ether, wirelessly speaking, that is:
Four LEDs, blinking according to the following status signals:
- RECV – blinks briefly for each received packet
- RSSI – shows the value of the RSSI bit in the RF12 status
- DQD – shows the value of the DQD bit in the RF12 status
- ALIVE – blinks at 1 Hz, just to show that this node is alive
I changed some thresholds to get better results: RSSI threshold -91 dBm and DQD set to 7 (normally -103 and 4, in the current RF12 driver).
Here is the sketch which drives the LEDs accordingly:
In this example, I’ve set up the RF12 parameters to receive group 5 in the 868 MHz band.
The result is quite interesting: DQD is flashing constantly, in an irregular pattern. RSSI blinks only once in a while, and some of these cause RECV to light up – as expected: only packets with the proper FSK format are filtered out, and only some of those are for this specific net group.
The reason for doing this will become clear tomorrow…