If anyone has run into this again,

ensure you update your /etc/modalai/voxl-tag-detector.conf to the tracking camera pipe you would like to do the april tag detection on.

the "tracking" has gotten update to "tracking_down" or "tracking_front"

@SystemBrute . The problem has been solved.

@psafi Here are the steps I am taking for camera calibration:

1- run the following command:
voxl-calibrate-camera tracking_down -f -s 6x9 -l 0.022

2- look at the overlay in portal (see the screenshot below)
3- calibration process is not progressing automatically even though it seems like the checkerboard is detected

e47c8511-c92f-4ce7-83f6-49d59dd89e7d-Screenshot from 2025-10-14 11-14-52.png

@Rupesh Apologies for the late reply
It looks like there’s an issue with how the AprilTag system is relocalizing the drone. In my tests, the z-value appears to be misinterpreted, which could explain why your drone was climbing in altitude to correct its height estimate. We’re actively working on a fix.

@Moderator Many thanks for your reply

Our goal is to develop a drone capable of indoor/confined-space autonomous flight without GPS, using SLAM-based navigation. The system should perform 3D mapping, obstacle avoidance, and full-area path planning.

We would like to confirm the correct set of components and the required algorithm stack.

Planned Algorithm Stack:

State Estimation: QVIO (Visual-Inertial Odometry) providing position and velocity to PX4/EKF2 via voxl-vision-hub. Mapping: voxl-mapper (TSDF/ESDF) using a depth source. Planning and Avoidance: voxl-mapper’s path planner or PX4 avoidance, using VIO as the pose source. Autopilot: PX4 running on VOXL2 via voxl-px4.

Proposed Hardware:

VOXL2 Autopilot – https://www.modalai.com/products/voxl-2?variant=39914779836467 VOXL2 Tracking Camera (Mono Global-Shutter) – required for QVIO (please confirm the correct part number). -- https://www.modalai.com/collections/image-sensors/products/msu-m0149-1 VOXL2 Compatible adapter https://www.modalai.com/products/mdk-m0076-1 VOXL2 Time-of-Flight (ToF) Depth Sensor – https://www.modalai.com/products/m0178?variant=48528287793456 VOXL2 Mini 40-Pin Connector ToF Adapter (MDK-M0172-1-00) – https://www.modalai.com/products/mdk-m0172-1-00

Questions:

Please confirm if this set (VOXL2 + Tracking Camera + Camera adapter + ToF sensor + ToF adapter) is sufficient for robust indoor SLAM navigation using PX4. For the tracking camera, which exact ModalAI part number is recommended for QVIO on VOXL2? Are there any best-practice configurations for voxl-mapper when using ToF instead of stereo depth? Would you recommend any additional sensors for improved performance in larger or more complex indoor environments?

Goal Summary:
We want the drone to hold position, generate a 3D occupancy map, avoid obstacles, and autonomously plan paths throughout the flyable space—without any GPS input.

Thank you in advance for your guidance and confirmation.

Best regards,
Nitin

@Rishi-gnanasegar There is not going to be an easy way to install after we have built the drone. It is not meant to be plug and play as the plastics are different based on which sensors have been ordered when the drone is ordered.

@adiprin1 On Ardupilot there is currently no way to use apps side UARTs (Some day we will add a method to use them). So, you would have to use one of the 3 UARTs attached to the DSP. If you removed the RC or the GPS and used that port then, theoretically, it could work. However, we have not tried that so can't make any guarantees. Also on PX4 you can use an apps side UART if there is one available on an add-on board. And, as you mention, you could use an SBUS RC on the VOXL 2 IO board and free up the standard RC UART.

Hi @SKA
Apologies no one responded promptly.
From what I gather, these are best to be sent back as an RMA and we can try to recover them.

D1 (green) is an indication of the local 3.3V power being Good. So, that implies you have 3.8V input, and the 3.3V reg is OK.
DS2 (RGB) is controlled by Qty-3 GPIOs from the SoC. This can briefly blink on boot until the GPIOs are configured by apps software.
D2 (green) is the 5V USB VBUS USB1 (10-pin) port power indicator, which only comes ON after the QRB5165 boots and Apps controls the GPIO to turn the VBUS ON.

On failed SW loads, it is common to diagnose that by seeing DS2 or D2 blink, which indicates boot loops. D1 should NEVER go off, if so, something is wrong in HW or cabling.

We do caution any customer that sets up their own CI or internal validation automation to include a nice pause before repeated power cycles. A common 5 second rule is good to let the large caps discharge, or certain ICs will never fully reset. This is the most common cause of "bricking" devices.

The RMA is your best bet here and we can try to recover them for you, or diagnose for any other issues: https://www.modalai.com/pages/rma

@mkriesel , just to confirm, does this test work (run) on other voxl2 boards for you?

@greg_s Great! Sounds good

@Aaron-Porter , perhaps systemd-timesyncd works together with systemd to correctly interpret the clock adjustments, so that run-time of systemd services is properly calculated.

Alex

@tom Thank you very much for your information.

Hi @QSL
OK, keep us posted!
Any, for any new issues, please be sure to start a new forum post so it is seen by the team.
Thanks!

@fhaltmayer It's not something we've explored

@crowley stinger is our FPV drone solution: https://www.modalai.com/products/stinger-vision-fpv?variant=48373207695664

We offer various levels of kit that can include goggles, transmitter, etc.

@marian Unfortunately VOXL1 has really been phased out but this board has the "fastboot" button on it and should work for you: https://www.modalai.com/collections/expansion-board/products/voxl-microhard-modem-usb-hub

@Alex-Kushleyev The IMU is being configured with an 8K ODR so by increasing IMU_GYRO_RATEMAX you are reading the FIFO more often but reading less samples each time. So you are mainly increasing the overhead of context switching. Can you characterize how much the load increases just by increasing IMU_GYRO_RATEMAX and not doing any of the extra UART IO? Unfortunately we don't have a lot of control over the low level implementation of the IO drivers that are in the Qualcomm code. And there is no DMA that could help lower IO overhead. One idea would be to lower the ODR to 1K so that you are only reading one sample from the FIFO at each interrupt.

@Allister-Lim ,

If you are not monitoring the battery voltage while working with your battery-powered VOXL, it is possible that you are over-discharging the batteries to the point of failure. Especially with LiPo batteries, it is unsafe to over-discharge them, so please be careful. (It seems that you are also using LiPo batteries, in addition to ModalAI Li-Ion batteries also shown (green)). There is nothing wrong with using LiPo batteries, but you have to be more careful with those. Over-discharged batteries lose capacity and Lipo Batteries may become dangerous.

It is a good idea to use an appropriate DC power supply when working with VOXL2 while it is powered on continuously. 12V 3-5A Power supply, connected to the APM (which will provide 5V for VOXL) should be sufficient. You should have no problem finding one, but in case you need, here is a link to the AC adapter that we sell : https://www.modalai.com/collections/accessories/products/ps-xt60

Alex