What?
LED illuminated gates (track markers for drone races) are a fantastic element to add both eyecandy and giving information to the pilots and the spectators.
Why?
- There are currently no price sensititve commercial solutions available
- A self developed IR remote solution was found to be unreliable
- An implementation using the ESPnow protocol was unreliable with simultaneously active 2.4 GHz ELRS remote control links
Idea!
Using a robust wireless LoRa communication between the gates and a gateway attached to the lap timer could enable dynamic control of the light effects in the gates from the existing race management web-interface.
LoRa?
The term stands for “Long Range” and is a popular technology in wireless communication. Semtech is one of the manufacturers of LoRa capable modems. LoRa is not intended to have a high usable bandwith but instead is optimized to be interference resistant. There are 433, 868 MHz and 2,4 GHz modems available. 2,4 GHz is not an option as this frequency is used by the pilots. This points to using 433 MHz or 868 MHz LoRa communication.
Why not use a cable based solution?
Cable based solutions have their own challanges like noise on long wires (min 100 meters for one racetrack), connectors (costly) or time intensive cable maintainance (unwanted). A robust automotive bus (LIN, CAN) could be an option but even those are intended for shorter cables. Of course there are long distance busses like RS-485 but cabled solusions are generally ruled out at the moment.
Functional Goals:
- Easy configuration of light effects along the race-track
- Individual (point to point) and grouped (broadcast) commands
- Upon powerup each gate enters an unconfigured state, waiting for config through the gateway.
- If no configuration is pushed within 3 minutes or the userbutton on the gate is pressed, the rf module will be disabled and a predefined effect can be selected
- When the gateway sees unconfigured gates the user can push the last configuration state for these devices or create a new group or device via the web-interface
- Create a light wave effect going along the path of the racetrack.
PoC Hardware Selection:
- Heltec HT-CT62 (ESP32C3 + SX1262 LoRa Node)
- ESP32 Dev Backplane
- Wireless Stick(V3), (ESP32S3 + SX1262 LoRa Node)
ToDo:
- Source Hardware -> done
- Create WLED Usermod for the LoRa communication interface
- Create LoRa gateway / server code
- Test the communication
- Design custom PCB for the gates
- Create RotorHazard Laptimer Plugin for interactive configuration