How To Connect
- Check requirements first!
You need a Graupner HoTT v4 compatible receiver / transmitter both with the latest firmware version. The implementation for ArduPilot is developing and testing using following environment: * MC-32 firmware v1.030 * GR-16 firmware v6a10_f9 * GR-12 firmware v3a40_e9
- If you prefer to deploy a precompiled ArduPilot package please continue here and after that skip to the next chapter how to create a patch cable.
- Download the Hott.pde and UserCode.pde files from the project website and copy it to you ArduCopter source directory ie. ardupilot-mega/ArduCopter
- Edit APM_Config.h file and add following line to bottom of the file:
#define HOTT_TELEMETRY
#define HOTT_TELEMETRY_SERIAL_PORT 2
#define HOTT_SIM_GPS_SENSOR
#define HOTT_SIM_EAM_SENSOR
#define HOTT_SIM_VARIO_SENSOR
#define HOTT_SIM_GAM_SENSOR
//Use HoTT Alarms
#define HOTT_ALARMS
In this example we are using APM2 serial port 2.
- Add Hott.pde Arduino project
Launch Arduino and load the ArduCopter sketch. Add Hott.pde file to this project by opening the Hott.pde file in Arduino. Compile and deploy the ArduCopter code.
- Create a patch cable
Create patch cable with shorted RXD uand TXD pins on one side and removed middle (power) wire on the other side.
APM2 HoTT receiver
RXD -------+-- Telemetry
TXD -1.5k -|
GND ---------- GND
- Connect the HoTT telemetry port from the receiver (marked with a capital T) to the selected APM2 serial port (usually port 2). Plug the side with the connected RXD/TXD wires to APM2 and the other side with the removed wire in the middle to the HoTT receiver. RXD/TXD are not connect directly but via a 1.5k resistor (thanks to Michael for this suggestion).
Note: The patch cable doesn't really requires the 1.5k resistor in series between TXD & RXD since the serial bus is specified up to 5v which has been confirmed by Graupner , but it is "best practice". The patch cable:
A picture from the receiver. There is no wire in the middle on the receiver side!
And on the APM2 side:
