CRSF Link tester and packet monitor

A testing tool for Crossfire and ExpressLRS receivers using M5 Core2 hardware

Features

Realtime graphical visualization of

• RSSI, LQ, Link Rate and TX power
• Up to 10 RC channels
• Scrolling colored indicator of received, bad and missed packets

User interface

RSSI bar, minimum range is based on RX sensitivity for given packet rate (ELRS)

• LQ: Link quality bar
• PW: Current power of the transmitter, for ELRS works only in WIDE switch mode
• PR: Current packet rate in Hz
• Numeric values and graphical bars for 10 RC channels
• Text and scrolling packet indicator: each vertical line reppresents a received (or not) RC packet:

Good RC packet received

RC packet timeout

Bad serial RX frame or CRC error

Update rate and packet timeout are based on link rate, packet timeout = (1 / PacketRateHz * 1.5) seconds **

It's OK to see red missed packets at regular intervals with telemetry turned on, because these time slots are used by receiver to transmit back the telemetry packet. Just turn off the telemtry to get rid of them.

Programming and flashing

Basically the process is the same as for ExpressLRS and VSCode, just modify the platformio.ini file and select the correct serial port for flashing How to compile with VSCode for ESP32

Limitations

• Tracer RX is not tested
• Currently supported only on M5 Core2 hardware, but could be easily ported on any other ESP32 based harware with any 320 x 240 display supported by TFT_eSPI library

Wiring diagram for M5 Core2