ModalAI Forum

Doodle Labs radios are pretty plug and play with the VOXL2, I've been working with that setup for a while. The breakout board used in that guide is one supplied by Doodle labs in an evaluation kit, but you don't really need it. The breakout board and radio shown in the pictures also seem to be older models, so the pinout and connections today are slightly different. The software setup is still the same, using voxl-configure-modem.
With the VOXL2, you just need this cable:

Cable Datasheets

ModalAI technical documentation for VOXL and VOXL 2 Companion Computers for PX4 and ArduPilot Obstacle Avoidance and GPS-denied navigation, assembled in the USA

ModalAI Technical Docs (docs.modalai.com)

and an add on board that has a 10-pin USB + power port such as this:

VOXL 2 USB3 UART Add-On

ModalAI technical documentation for VOXL and VOXL 2 Companion Computers for PX4 and ArduPilot Obstacle Avoidance and GPS-denied navigation, assembled in the USA

ModalAI Technical Docs (docs.modalai.com)

Then just connect the 6 pin cable to the mini oem's power port (port 4), and the 4 pin cable with the twisted wires goes to the mini oem's USB port (port 1), the mcbl-00085 link has some drawings. Then on the VOXL just run the configuration script. Also the radio can get hot pretty quickly so be wary of that.
If you're using a mini oem for the GCS side you don't really need that breakout board from doodle labs, you just need a 5V 2-3A regulator to power the mini oem on port 4, and there is a Rj45 ethernet adapter from Ark Electronics that matches the pinout of the radio's ethernet port, and I like to connect it to the mini oem's ethernet port (port 2) for my GCS device to use, but you can also just use a USB-A to JST adapter connected to port 1 instead.

@Karteek-Gandiboyina the gps drivers on px4 1.14 don't support that gps, it fails some configuration step if I remember correctly and that's why it gets stuck in a detected loop. Switching to mainline px4 worked for me.

Hello is the M0094 RB5 Flight Spektrum Binding Module available for purchase?

@Eric-Katzfey One more update, I ended up upgrading the firmware to v1.14.0-2.0.98 for all the flight core units that I have and I'm confident the barometer missing issue is gone now. Thank you for your help and your quick responses.

@Eric-Katzfey That is strange, I just upgraded the firmware to v1.14.0-2.0.98 on one of my flight core units, I got rid of the micro sd and the extras.txt file as well and I don't seem to get the "barometer sensor 0 missing" error anymore. Interestingly /etc/init.d/rc.board_sensors is the exact same so something else may be going on instead.

nsh> cat /etc/init.d/rc.board_sensors | grep -nE 'icp201|bmp388'
board_adc start
voxlpm -X -b 3 -k -T VBATT start
voxlpm -X -b 3 -T P5VDC start
icm42688p -s -b 1 -R 12 start
icm42688p -s -b 2 -R 12 start
icp201xx -I start
if param greater VOXL_ESC_CONFIG 0
then
usleep 1500000
voxl_esc start
fi
nsh: cat: open failed: No such file or directory
nsh> 

@Eric-Katzfey
Hello, thank you for responding, the PX4 version is 1.14

nsh> ver all
HW arch: MODALAI_FC_V2
HW type: V2003000
HW version: 0x003
HW revision: 0x000
PX4 git-hash: 5e6a8c257371b6c45e55662daac5fe9fbd08040b
PX4 version: 1.14.0 0 (17694720)
Vendor version: 2.0.94 0 (33578496)
OS: NuttX
OS version: Release 11.0.0 (184549631)
OS git-hash: 3f77354c0dc88793a47ff3b57595195ab45f7ba9
Build datetime: Feb 20 2025 01:58:47
Build uri: localhost
Build variant: default
Toolchain: GNU GCC, 9.3.1 20200408 (release)
PX4GUID: 0006000000003333363031315106002b0036
MCU: STM32H7[4|5]xxx, rev. V
nsh>

I noticed that /etc/init.d/rc.board_sensors is where icp201xx -I start is ran:

nsh> cat /etc/init.d/rc.board_sensors | grep -nE 'icp201|bmp388'
board_adc start
voxlpm -X -b 3 -k -T VBATT start
voxlpm -X -b 3 -T P5VDC start
icm42688p -s -b 1 -R 12 start
icm42688p -s -b 2 -R 12 start
icp201xx -I start
if param greater VOXL_ESC_CONFIG 0
then
usleep 1500000
voxl_esc start
fi

I didn't want to mess with the file (not sure if I can), so I just installed a microsd card to the flight core and created this file:

nsh> cat /fs/microsd/etc/extras.txt
usleep 2500000
icp201xx stop
usleep 300000
icp201xx start -I -b 4 -a 0x63 -q
nsh> 

just icp201xx start -I should also work, but I have repowered this flight core and used it on other flight cores multiple times and this issue no longer occurs. My guess is it's just a timing issue, icp201xx start is probably failing in rc.board_sensors because the barometer rail isn't fully up at that moment.

@Eric-Katzfey Hello I am also getting "barometer 0 missing" occasionally, a reboot or two also usually fixes it for me. I get it occasionally even when I'm powering the flight core V2 only on my drone (nothing else on my drone is powered), using J3 USB connector. I also just tested it with another flight corev2 unit, one that is fresh and not on any drone and also just powered with J3, it also gets this error. It seems that whenever It's initially powered, the barometer won't be detected until I reboot.
I did some further debugging using the MAVlink Console in QGC, it seems when the "barometer sensor 0 missing" occurs the icp driver doesn't actually start.

nsh> icp201xx status
INFO [SPI_I2C] Not running
nsh> icp201xx start -I
icp201xx #0 on I2C bus 4 (external) address 0x63
nsh> listener sensor_baro
TOPIC: sensor_baro
sensor_baro
timestamp: 253700745 (0.020062 seconds ago)
timestamp_sample: 253698133 (2612 us before timestamp)
device_id: 12084001 (Type: 0xB8, I2C:4 (0x63))
pressure: 96713.71094
temperature: 51.86063
error_count: 0

@gestrada1150
I think it should come with gps denied navigation configuration out of the box, you can verify and set it up yourself here:
https://docs.modalai.com/flying-with-vio/

@Alex-Kushleyev , Thank you, I successfully ordered the it.

Hello, I can't seem to find the M0202 Hadron640R adapter on the product store,
It is mentioned in this guide and the PCB catalog.
https://docs.modalai.com/voxl2-hadron/