How to connect VOXL to Pixhawk Telemetry to send data over WiFi or LTE

Table of contents

  1. Overview
  2. Requirements
    1. Hardware
    2. Target Software
    3. Host System
  3. Usage
    1. Hardware Setup
    2. Network Configuration
    3. Run The Demo Application
  4. Application Customization



The VOXL provides the ability to stream MAVLink telemetry data between flight controllers and ground control stations. In this user guide, a Pixhawk 4 Mini and QGroundControl are used.

A demo application ships on the VOXL and provides the ability to relay MAVLink messages through the SLPI DSP over UART (J12) to the Pixhawk, and over Wi-Fi to QGroundControl.

One could alternatively do this over LTE following the guide here and the addition of a VPN connection (a user guide on this soon to come)!

The application’s source code is available here, and the Dockerized build environment is available here, so one could customize as needed.



  • Host computer (Ubuntu 18.04 used in this guide)
    • VOXL Core Board (MCCA-M0006)
    • Wi-Fi antennas (MANT-00001)
    • APM Regulator Board and cable (MCCA-M0009 and MCBL-00001 cable)
    • 5V/6A Power Supply (MPS-00001-1, MPN: WR9QA6000LCP-N(R6B) with Q-NA(R))
  • Micro USB cables
  • Pixhawk 4 Mini (or equivalent)
  • A custom cable with the following pinout:
VOXL - J12, DF13-6S-1.25C connector Pixhawk 4 Mini - TELEM1
Pin 1 NC
Pin 2 - TX Pin 3 - RX
Pin 3 - RX Pin 2 - TX
Pin 4 NC
Pin 5 - GND Pin 6 - GND
Pin 6 NC

Target Software

  • Download the slpi_uart package here
  • Install the package to the target:
adb push slpi_uart_x.x.x.ipk /home/root/ipk
adb shell "opkg install /home/root/ipk/slpi_uart_x.x.x.ipk"

Host System

Host computer with:


Hardware Setup

  • Disconnect power from the VOXL
  • Ensure Wi-Fi antennas are attached (see here for details)
  • Connect the VOXL’s J12 to the Pixhawk 4 Mini’s TELEM1 using the custom cable described above
  • Reconnect power

Network Configuration

  • Configure the VOXL as an Access Point (or connect it to a network)
    • instructions on how to do this are here
  • Connect the host computer to the VOXL’s Access Point (default password is 1234567890) or to the same network you connected the VOXL to
  • Locate the host computer’s IP Address and note it for later

Run The Demo Application

  • Run QGroundControl on the host computer
  • Power the VOXL on
  • Power the Pixhawk 4 Mini using USB for this bench test
  • SSH onto the target (see here for details)
  • Run the telemetry proxy application using IP address noted above
telem_proxy <Host IP Address>

Application Customization

The application’s source code is available here under the telemetry_proxy example. To easily customize and build the application, the Dockerized build environment is also conveniently available here.

Copyright (c) 2019 ModalAI Inc.