Antenna Interfacing

[dimembermatt]

For communicating with the litterbug, we are using the Adafruit RFM69HCW Packet Radio Breakouts. This is a radio transceiver modules for long distance data communication.

With an SPI interface, this breakout has 9 pins you need to look at:

• VIN/GND - needs 3.3-6VDC and >=150mA supply. This is likely going to have to be supplied by a separate power source.
• EN - connected to the enable pin of the regulator, pulled to Vin by default - the microcontroller can can connect a pin to this and pull it low to cut power to the microcontroller.
• SCK - GPIO 11
• MISO - GPIO 9
• MOSI - GPIO 10
• CS - GPIO 8 (CE0)/ GPIO 7 (CE1)
• RST - pull LOW to turn on the radio - GPIO 5
• G0 - hardware interrupt - GPIO 8

Further information on the RPI's SPI is found here. A complete pin mapping of the final robot is found here in sheet Final Pinout.

Choosing an antenna Further information on setting up and testing the module Test Code for pi and companion transceiver General guide on the breakout by Adafruit (arduino code)

In order to test the radio transceiver, you need a secondary radio to send and receive data. A possibility is the Adafruit Feather m0. It comes fully assembled and tested, and easy to power on and start up. It requires a lipoly battery and USB. Use with Arduino IDE.

This task needs the following completed:

• [x] parts need to be ordered
• [x] prototype breadboarding circuit needs to be assembled
• [ ] pins and antennae need to be soldered to the breakout
• [x] test software needs to be written for both the pi and the feather
• [ ] the pi can receive and send simple communication packets at 433MHz
• [ ] generic commands need to be made to send arbitrary packets (protocol to be determined by the hosts)
• [x] program made as a separate thread in order to constantly operate during normal operation

[dimembermatt]

Update 2/20/20:

I've agreed with Ramsey that this project can be done independently using two Feather M0s. One of the Feather M0s can be logically disconnected from the rpi (there will be a switch connecting the two to turn them both on/off simultaneously).

On game startup, pressing the power switch will power the Feather on, and it will continuously attempt to receive/broadcast litter bug messages until power off.

Since the Feather uses arduino code (C++), the following code can be adapted. Node code can be found here.

Possibly helpful documentation:

• https://learn.adafruit.com/adafruit-feather-m0-radio-with-lora-radio-module/using-the-rfm-9x-radio

This task has been reduced to the following:

• [ ] parts need to be ordered
• [ ] test software needs to be written for basic TX/RX
• [ ] design a system to communicate with the litter bug (this is the big one)
• [ ] figure out how to turn off with switch