@dlee ,

Yes the new TOF sensor (IRS2975C) is more powerful that the previous generation. What I mean by that is that it can emit more IR power but also heats up more. Emitting more power allows the sensor detect objects at larger distances or objects that are not as reflective.

In current operating mode, the auto exposure control is enabled inside the sensor itself, which modulates the emitted IR power based on the returns that the sensor is getting. That is to say, the power draw will vary depending on what is in the view of the sensor. If there are obstacles nearby, the output power should be low, otherwise it can be high. At full power, the module can consume close to 0.8-0.9W

So the first solution, if design allows, is to add a heat spreader to dissipate the heat, which you already started experimenting with. The sensor has a large exposed copper pad in the back for heat sinking purposes for this exact reason. Just be careful not to short this pad to anything, use non-conducting (but heat transfering) adhesive pad between the sensor and heat spreader.

In terms of a software solution to the issue, we can query the temperature of the emitter. We can also control the maximum emitted power used by the auto exposure algorithm. That is to say, still leave the auto exposure running in the sensor, but limit the maximum power that it is allowed to use.

We are planning to add some software protection that limits the maximum output power as a function of the emitter temperature. This will require some implementation and testing.

Meanwhile, please consider using a heat spreader, which will be the best solution if you want to make use of the full sensor's operating range and not have our software limit the output power in order to prevent overheating.

Hello @Kashish-Garg-0

we have a curve that is "motor voltage vs rpm", meaning that for a desired RPM, it tells the ESC what average motor voltage should be applied. The average motor voltage is defined as battery_voltage * motor_pmw_duty_cycle. The battery voltage in this curve is in millivolts. Since you are typically controlling the desired RPM, as a user you do not need to worry about what "throttle" or voltage to apply - the ESC does this automatically in order to achieve the desired RPM. this calibration curve is used as a feed-forward term in the RPM controller. The ESC does support an "open loop" type of control where you specify the power from 0 to 100%, which is similar to a standard ESC, but PX4 does not use that ESC control mode.

By the way, you can test the ESC directly (not using PX4) using our voxl-esc tools (https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/tree/master/voxl-esc-tools) which works directly on VOXL2 or a standalone linux PC (or mac). voxl-esc-spin.py has a --power argument where you specify the power from 0 to 100, which translates directly to the average duty cycle applied to the motor.

Here is the calibration for the Starling V2 motor / propeller that we use:
https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/master/voxl-esc-params/mavic_mini_2/mavic_mini_2.xml?ref_type=heads#L63

Also, you can take a look at this post to see how to interpret those parameters a0, a1, a2 : https://forum.modalai.com/topic/2522/esc-calibration/2

We also have some dyno tests for this motor / propeller : https://gitlab.com/voxl-public/flight-core-px4/dyno_data/-/blob/master/data/mavic_mini2_timing_test/mavic_mini2_modal_esc_pusher_7.4V_timing0.csv . We are not sure how accurate that is, but it can be used as a starting point. @James-Strawson can you please confirm that is the correct dyno data for the Starling V2 motors?

Alex

@reber34 , perhaps this approach can work for you:

• record a video encoded at high bit rate (using voxl-camera-server and voxl-record-video . Please note that the output of voxl-record-video will not be in a standard container (such as mp4, etc), but you can fix it with ffpeg : ffmpeg -r 30 -i voxl-record-video.h264 -codec copy videofile.mp4
• re-encode the video offline with desired codecs / bit rates / resolutions
• install gst-rtsp-launch which uses gstreamer to set up an RTSP stream https://github.com/sfalexrog/gst-rtsp-launch/
  • you will first need to figure out what gstreamer pipeline to use on voxl2 that will load your video and parse the h264/h265 frames (can use null sink for testing) and then use that pipeline with gst-rtsp-launch which will take the encoded frames and serve them over rtsp stream.
• gstreamer may be more flexible for tuning the encoding parameters of h264/h265 (compared to voxl-camera-server) and you can also use it in real time later (using voxl-streamer, which uses gstreamer under the hood)

Another alternative is to use voxl-record-raw-image to save raw YUVs coming from voxl-camera-server and then use voxl-replay and voxl-streamer - the latter will accept YUVs from the MPA pipe and encode them using the bit rate that you want. Note that depending on the image resolution, YUV images will take a lot more space than encoded video, but maybe that is also OK since VOXL2 has lots of storage.

Alex

@jimbow77 and @oasisartisan ,

TOF V1 (which is now EOL, so you don't have it on Starling 2 Max) was set up the following way:

• The calibration data was downloaded the first time the sensor was used and stored in /data/misc/camera/, then re-used for next time
• calibration files include pmd.spc, tof_cal_eeprom.bin and irs10x0c_lens.cal - the latter likely containing the intrinsics calibraiton data (although i have not checked explicitly)

TOF V2 (what is shipping in Starling 2 (and Max) ), is set up so that the TOF Library downloads (via i2c) the calibration data each time the voxl-camera-server starts. This is done internally to the TOF libraries. I don't know exactly why there is a difference between how the calib data is handled for two sensors by the TOF software, but this is how our sensor vendor helped us set it up. The TOF processing software downloads the calibration from the sensor each time voxl-camera-server starts and applies it to generate the point cloud. It may be possible to get the TOF intrinsics using the TOF library API, but we have not checked.

Do you have a specific reason why the TOF intrinsics are needed?

If you wanted to calibrate the TOF sensor yourself, then you would either need a checkerboard some material that is IR reflective ("white") and non-reflective ("black"). Alternatively, you could use an array of IR leds (or IR reflective dots + IR light) and use dot pattern detector as opposed for checkerboard for calibration.

Regarding Hi-res cameras, the intrinsics are not calibrated and not included. It can be calibrated using our camera calibration app (voxl-camera-calibration), but you should do it at half resolution or smaller (not full size like 4056x3040), otherwise the app runs very slowly. If you need more details how to calibrate at high resolution, let me know (involves downscaling exactly by a factor of 2 and then upscaling the resulting intrinsics)

Alex

@smilon , voxl-esc-calibrate.py is a script that runs a test procedure in a single motor (with propeller mounted) to calibrate the behavior of the motor / propeller. This procedure only needs to be run once if you change motor or propeller type from a default configuration. The output of this script is just 3 coeficients a1, a2, a3 which you would need to manually enter into an ESC calibration xml file and then upload the xml paramer file to the ESC. Full details about the ESC calibration (when to do it and how) can be found here : https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/master/voxl-esc-tools/calibration.md?ref_type=heads

If you are using standard motors and propellers (one of standard ModalAI drones), you do not need to run this calibration procedure.

It sounds like you got it working, I believe voxl-configre-mpa took care of it. You can see what voxl-configure-mpa typically does here : https://docs.modalai.com/voxl-configure-mpa/ , which includes running voxl-esc to upload the latest firmware and params for a specific vehicle.

Hello @Gicu-Panaghiu,

I am going to assume you are using VOXL1, since you did not specify..

We do have RAW8 and RAW10 support for OV7251. The selection of the format has to be done in several places.

First, you have to select the correct camera driver, specifically..

ls /usr/lib/libmmcamera_ov7251*.so
/usr/lib/libmmcamera_ov7251.so
/usr/lib/libmmcamera_ov7251_8bit.so
/usr/lib/libmmcamera_ov7251_hflip_8bit.so
/usr/lib/libmmcamera_ov7251_rot180_8bit.so
/usr/lib/libmmcamera_ov7251_vflip_8bit.so

there are 5 options and one of them is _8bit.so which means it will natively ouptput 8bit data (all others output 10 bit data).

the driver name, such as ov7251_8bit has to be the sensor name <SensorName>ov7251_8bit</SensorName> in /system/etc/camera/camera_config.xml.

You can check camera_config.xml for what sensor library is used for your OV7251.

When you run voxl-configure-cameras script, it will actually copy one of the default camera_config.xml that are set up for a particular use case, and I believe it will indeed select the 8bit one - this was done to save cpu cycles needed to convert 10bit to 8bit, since majority of the time only 8bit pixels are used.

Now, you mentioned that HAL_PIXEL_FORMAT_RAW10 is passed to the stream config and unfortunately this does not have any effect on what the driver outputs. If the low level driver (e.g. libmmcamera_ov7251_8bit.so) is set up to output RAW8, it will output RAW8 if you request either HAL_PIXEL_FORMAT_RAW8 or HAL_PIXEL_FORMAT_RAW10.

So if you update the camera_config.xml to the 10bit driver and just keep the HAL_PIXEL_FORMAT_RAW10 in the stream config (then sync and reboot), you should be getting a 10 bit RAW image from the camera. But since the camera server is currently expecting 8 bit image, if you just interpret the image as 8 bit, it will appear garbled, so you will need to handle the 10 bit image (decide what you want to do with it) in the camera server.

@jakkkkobo ,

The source code of voxl-send-neopixel-cmd test tool is here : https://gitlab.com/voxl-public/voxl-sdk/services/voxl-io-server/-/blob/master/tools/voxl-send-neopixel-cmd.c

The function that creates a binary packet (which is forwarded to the ESC via PX4) is here : https://gitlab.com/voxl-public/voxl-sdk/services/voxl-io-server/-/blob/master/lib/modal_io.c#L181 . Basically you need to provide the following information to this function:

• number of LEDs you are controlling
• LED type (RGB or RGBW)
• array of LED colors (3 bytes for each LED in case of RGB, or 4 bytes per LED for RGBW).
• the array should contain all LED values ranging from 0-255, so if you had 3 LEDs and first should be red, second green and third blue (50% power), the LED color array would be : [127, 0, 0, 0, 127, 0, 0,0,127].
• this function will create a packet with checksum and send it to PX4, and PX4 will forward the packet to the ESC.

You can modify the voxl-send-neopixel-cmd to do what you need, maybe you can make it accept an array of LED color values via command line.

I know the tool could have been more helpful. If you describe your use case, maybe I can help improve the voxl-send-neopixel-cmd tool.

Alex

@KnightHawk06 , use voxl-calibrare-camera tracking_down_misp_grey <remaining options>

The ipk is available here now : http://voxl-packages.modalai.com/stable/voxl-hal3-tof-cam-ros_0.0.5.ipk - you should be able to use the launch file to choose between two modes (5=short range and 9=long range) and fps, which are listed in the launch file.

@Moderator said in VOXL ESC Mini 4-in-1 Current per Motor:

Is it possible to step up voltage?

Can you please clarify the question?

Mini ESC is designed for small drones ( < 500g ). The ESC has been tested to handle 15A continous at 15V input continuously (60+ seconds), but with full direct air flow from propellers. This would simulate a full throttle "punch-out" on a small FPV drone (high current, but also lots of direct airflow = cooling). Do not use this ESC if the drone needs 10-15A per channel just to hover. Use it in application where hover current per motor is less than 5A (ideally 2-3A which is very typical) and absolute maximum continuous current per motor can be 10-15A.

For example, motors used for small FPV drones often are around 1306 size (3-4S Lipo). Those motors are usually rated for up to 10-12A continous (for 30-60 seconds). Larger motors can be used as long as maximum motor current does not exceed 10-15A (still 2-3A at hover) and there is sufficient cooling.

Always check ESC board temperature during initial flights / tuning. Temperature must stay below 110C at all times (critical), typically in the range of 40-70C for most applications. The ESC will most likely fail above 125C.

Temperature of the ESC board is the limiting factor because the board is so small. Mosfets can handle a lot of current as long as they don't overheat. So the design of the drone is very important (either use low current so that temperature is not an issue or properly design air flow from propellers and/or add heat spreader to keep the ESC board temperature in normal range for higher current draw applications).

ESC provides real time temperature feedback and it can be viewed in PX4 / QGC. Additionally, the PX4 logs contain the temperature information.

Hi @irw ,

This seems like a hardware issue, potentially related to PMIC. Are you able to share full dmesg output from boot, when this issue is happening?

One thing to try would be to disconnect M0173 board from VOXL2 and see if you can reproduce the same messages related to cam_sensor*power_up -- these are definitely not normal. Perhaps there is a short on one of the camera power rails, which is preventing PMIC from working properly.

Alex

Hi @jameskuesel ,

Yes there is an issue when both MISP and snapshot are enabled. I will look into it again.

By the way, what snapshot are you looking to grab? There are a few options;

• a frame from high-res recording (with eis?)
• a frame from low-res streaming (with eis?)
• full frame, full resolution (no stabilization)
  • what format? jpg or raw bayer (for offline processing)

We can implement a snapshot feature in MISP (and not going through ISP).

Alex

@Noah-Heinen , unfortunately it is not possible to add a TOF sensor to your current Voxl2 Mini configuration. M0188 adapter does not support TOF.

The only way this would be possible is:

• remove M0188
• add M0172 and connect TOF and either M0186 or M0166 camera
• add another M0172 or M0194 and plug in a single camera. Unfortunately right now we don't have a small adapter like M0172 or M0194 that supports two standard cameras like M0166 or M0186.

So you would probably be losing one of the tracking cameras if you want to add a TOF sensor.

Alex

@Jskim , maybe it's ok that the Device ID is increasing, however it could mean the USB device is not de-initializing properly (according to the Kernel). Perhaps the device is still open / in use by voxl-uvc-server when you power the camera off (switch to the SD card mode).

Please see some more information below that may be helpful.

Fix 1: Configure voxl-uvc-server to identify the camera by Vendor/Product ID

Instead of relying on the device index, tell voxl-uvc-server to always find your camera by its USB VID:PID. This is the most robust approach.

Step 1: Find your camera's Vendor ID and Product ID

lsusb

Look for your UVC webcam in the output. The ID is in VENDOR:PRODUCT hex format, e.g.:

Bus 001 Device 003: ID 090c:337b  <-- vendor=090c, product=337b

You can also use the ModalAI helper script:

show-video-device-info.sh

Step 2: Update the voxl-uvc-server service to pass VID/PID

Edit the systemd service override so the server always targets your specific camera:

mkdir -p /etc/systemd/system/voxl-uvc-server.service.d/
cat > /etc/systemd/system/voxl-uvc-server.service.d/override.conf << EOF
[Service]
ExecStart=
ExecStart=/usr/bin/voxl-uvc-server -v <your-vendor-id> -p <your-product-id>
EOF
systemctl daemon-reload
systemctl restart voxl-uvc-server

Replace <your-vendor-id> and <your-product-id> with the hex values from lsusb. With this in place, voxl-uvc-server will find the camera by identity rather than by device node index, so it will survive power cycles without needing a manual restart.

Fix 2: Create a udev rule for a persistent /dev symlink

This assigns a stable name (e.g., /dev/uvc_cam) to your camera regardless of enumeration order:

cat > /etc/udev/rules.d/99-uvc-camera.rules << EOF
SUBSYSTEM=="video4linux", ATTRS{idVendor}=="<your-vendor-id>", ATTRS{idProduct}=="<your-product-id>", SYMLINK+="uvc_cam", MODE="0660"
EOF
udevadm control --reload-rules
udevadm trigger

After this, /dev/uvc_cam will always point to your camera. You can reference this stable symlink in any configuration.

Fix 3: Check dmesg for resource leak warnings

If the device ID keeps incrementing (e.g., /dev/video0 → /dev/video1 → /dev/video2...) rather than re-using the same node, there may be an underlying resource leak from improper de-initialization:

dmesg | grep -i "uvc\|video\|usb" | tail -50

Look for warnings about disconnection or failed cleanup. If the ID increments indefinitely, this points to a kernel-side resource not being released properly on power-off — that may require a deeper fix or a systemctl stop voxl-uvc-server before powering down the camera.

Summary

The vendor/product ID approach (Fix 1) should eliminate the need for the manual systemctl restart workaround entirely.

@syamala-kotireddy ,

If the ESC is not showing any signs of life (no blue led blink), it probably means the ESC power regulator is not working properly. However, you mentioned that VOXL2 is actually booting fine? Can you measure the voltage on the connector / pads that provide 5V power from M0129 ESC to VOXL2?

Please see the following post, where a capacitor on the ESC next to the main voltage regulator was knocked off, resulting in ESC not starting up. https://forum.modalai.com/topic/4151/voxl-mini-4-in-1-esc-missing-capacitor/ . However, in that post, i think VOXL2 was not booting either. In your case the issue may be something different.

It is worth carefully inspecting the ESC.

Also, if you have a power supply that can measure current, you can set it to 8V and measure the current draw of the ESC alone, it should be very small (maybe 20-30mA) but not zero.

Alex

@restore , the change to enable the maximum resolution raw output for OV64B was made at the end of October 2025, so you would need at least SDK 1.6.0, I believe. There was a change in the camera pipeline (not the camera driver) to allow such a large image size. Are you able to test on a newer SDK (just test the latest if you can)?

Additionally, the resolution 9248x6944 cannot be directly used in MISP debayering (which uses OpenCL). There are some special requirements on the image stride, which width of 9248 does not match. So what will happen is the cpu will realign the image before feeding it to the gpu, but it is a lot of data to copy for a 64Mpix sensor. So I made a small change in width from 9248 to 9216 (just cut off 32 pixels) and it can be fed into the gpu directly. That change is not published yet, but i can share it.

Lets first confirm that you can use the 1.6.x SDK to start the camera server at 9248x6944 and you should be able to save raw bayer and view the misp output.

you can always double check the list of available raw resolutions using voxl-camera-server -l

by "start the misp output stream", i mean that you need to have a client that subscribes to the misp output stream, so that the frames start going and AE can work, sending exposure and gain updates to the camera, so that the image is properly exposed. For example, viewing the stream in voxl-portal or just using voxl-inspect-cam hires_misp_color to get the data flowing, then you can save the raw bayer, which will have the proper exposure and gain applied.

Alex

@Michael-Soul , it is EAR99

@restore , a few more things:

• you should set the auto exposure to lme_msv, which is the non-isp option, since we would not be using isp in this case
• before saving the raw bayer, start the misp output stream, so that AE can actually process, otherwise the exposure will be stuck in default value -- the bayer stream does not trigger AE to process.

Alex

@restore, that is strange. Does this effect appear in the jpeg snapshot only? (as opposed to the preview stream).

Yes, we do support saving raw bayer10 for this camera. For 9248 x 6944, each image would be something like 80MB (10-bit bayer)

In order to test it,

• set your preview width and height to 9248 x 6944
• en_raw_preview : true
• en_snapshot : false (for now)
• en_misp : true
• set misp width and height to something reasonable (1920x1080)

When you run it, assuming there are no errors, you should see hires_bayer pipe and you can dump individual images using voxl-record-raw-image tool.

I have not tested this in a while, but it should work. Let me know if you run into any issues.

Also, please use an SDK that is not older than few months, as we recently enabled the full raw resolution support for this camera.

Regarding the jpeg smoothing, the parameters are baked into the chromatix tuning file and we have not tuned that for any particular application. However, you should first check whether the jpeg encode quality is sufficiently high. snapshot_jpeg_quality param in your voxl-camera-server.conf is set to 75.

Alex

@austin-c , The GPS driver is built for SLPI as well as APPS PROC, so you could connect it to a apps-proc UART and start the driver on the apps proc side of PX4.

This was done on RB5 : https://docs.modalai.com/Qualcomm-Flight-RB5-linux-user-guide/

https://docs.modalai.com/voxl2-linux-user-guide/

Regarding magnetometer, just like with the GPS driver, you should be able to enable the mag driver to build for apps proc. Since the apps proc i2c uses standard posix interface, it should just work. However, i don't think we have ever tried it.

Alex