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M0184 Software Guide

Table of contents

  1. Summary
    1. Components
    2. Software Block Diagram
  2. Use Cases
    1. voxl-elrs Utility
    2. Setting Up PWM Pins
    3. Setting PWM Over IP
      1. Summary
      2. PX4 Params
      3. Transmitter setup
      4. Example Usage
      5. Failsafe

Summary

Components

Component/RepoNotes
elrs-build-dockerDocker container that can clone/build FW with ease
VOXL SDKUsed to deploy all required software/firmware components to VOXL / ELRS hardware
ExpressLRSFork of Express LRS supporting ELRSv1 (goal is to mainline) that runs on ELRS v1 (M0184)
crsf_rcPX4 driver running in voxl-px4 that communicates over CRSF to ELRS v1 hardware
voxl-elrsVOXL2 command line utility, used to update FW/config on ELRS v1 from VOXL2, part of the SDK
FW bootloaderOpen source ExpressLRS bootloader

Software Block Diagram

Use Cases

voxl-elrs Utility

See voxl-elrs utility on target.

Setting Up PWM Pins

Up to four PWM pins can be configured. Examples of config files that can be loaded in:

Stinger Vision FPV

Setting PWM Over IP

Summary

SDK 1.5.0 or newer required.

Using a Transmitter as a USB joystick, you can setup a switches to buttons and map these to PWM channels physical on the M0184 radio, supporting the ability to set PWM values over IP connections.

PX4 Params

RC_CRSF_BUTTON1 through RC_CRSF_BUTTON8

  • Selects a button as input that will be mapped to a PWM channel output
  • NOTE : If you notice PWM behavior which resembles correct funtionality but shifted over by 1, re-assign current parameter values to one button higher.

RC_CRSF_PWMCHN1 through RC_CRSF_PWMCHN8

  • Selects a PWM channel output for button1 through button8

RC_CRSF_PWMVAL1 through RC_CRSF_PWMVAL8

Transmitter setup

If using a normal RC transmitter as a USB Joystick such as a RadioMaster Zorro there is a little bit of manual setup required in order for QGC and other applications to recognize the buttons correctly. If using a Logitech USB controller or other where buttons enumerate automatically this section can be skipped.

The following instructions were compiled using a RadioMaster Zorro connected via USB-C to the host PC.

edgeTX v2.10+ is required, in order to validate FW version:

  • Press the SYS button, which will bring you to the TOOLS page
  • Press the PAGE < button to navigate to the VERSION page
  • Confirm edgeTX version is >= v2.10

In order to upgrade FW version, follow the instructions here: https://manual.edgetx.org/installing-and-updating-edgetx/update-from-opentx-to-edgetx-1 https://manual.edgetx.org/edgetx-how-to/access-dfu-and-bootloader-mode

In order to translate the RadioMaster Zorro’s channel mappings to buttons. do the following:

  • Press the MDL button
  • Press the PAGE > button once to navigate to the SETUP page
  • Scroll all the way to the bottom until you see the USB Joystick section
  • In the USB Joystick section, set Mode to Advanced
  • Set If.mode to Joystick
  • Set Circ. cut to None
  • Navigate to [Channel Settings] and press enter

  • Set CH1 - CH4 to X, Y, Z, rotX (NOTE: The channels used for switches/buttons need to be on channel 9 or above for them to populate in QGC)

  • In the [Channel Settings] menu, navigate to the channel you’d like to setup, i.e. CH9
  • Set Mode to Btn
  • Set Positions to either 2POS or 3POS depending on the physical switch
  • Set Button no. to be the button numbers in QGC that you’d like this switch to populate (NOTE: A 2POS switch requires two buttons (0,1), whereas a 3POS switch requires 3 buttons (0,1,2))
  • Return to the home screen
  • Press the MDL button
  • Press the PAGE > button 5 times to navigate to the MIXES page
  • Scroll down to the corresponding channel which was setup, i.e. CH9
  • Select each channel to be used (hold down button) and set the source as the physical switch you’d like to link to the channel
  • In order to finalize changes you may need to disconnect and reconnect the joystick or restart QGC

Example Usage

Let’s say a LED bar was soldered to PWM pin P0, and configured for RC channel 7 (for example Stinger Vision FPV).

A PWM value of 1000 turns it off, a value of 1500 turns it to IR, and a value of 2000 turns it to visible light.

On an RC trasnmitter, we configure a 3-pos switch to map to buttons 1, 2 and 3.

In voxl-px4, we set PX4 params using params/v1.14/radio_helpers/pwm_via_elrs.params:

  • RC_CRSF_BUTTON1 to 1, RC_CRSF_PWMCHN1 to 7, RC_CRSF_PWMVAL1 to 191* (This maps to 1000)
  • RC_CRSF_BUTTON2 to 2, RC_CRSF_PWMCHN2 to 7, RC_CRSF_PWMVAL2 to 992* (This maps to 1500)
  • RC_CRSF_BUTTON3 to 3, RC_CRSF_PWMCHN3 to 7, RC_CRSF_PWMVAL3 to 1792* (This maps to 2000)

*See PWM value mappings here

Failsafe

  • When IP connection is connection and lost - TODO
  • When IP connection is connected and RC connection gained and lost - TODO