Hacking the 3DR Telemetry USB transmitter.

Post date: Feb 13, 2016 4:7:57 AM

In order to be able to use the USB 3DR telemetry transmitter some hack must be done directlyon the board.

The kit is using a HM-TRP Series 100mW Transceiver modules V1.0 ( check datasheet attached below).

This board is powered by 3.3VDc and provide RX txin TTL signal.The 3DR board hosting the HM-TRP Board add a serial to USB port and 5V to 3.3VDC voltage regulator.

I just need to solder 4 small cable on the HM-TRP Board as described above.

For the 3.3 Vc a l4931 regulator and 2 capacitor will do the trick.

You can still use the usb port on your laptop if the transmitter is disconnected from the arduino board.

Diagram:

Code:

To avoid disconnecting and reconnecting wire each time i want to upload a new sketch, the DTX and DRX of the HM-TRP will be connected on pin D8 D9 on the arduino and accessed via the software serial library.