@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

@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.

@wilkinsaf , M0027 was never shipped to any customers, as it was a test version of the ESC. So there should only be M0049, M0117, M0134 and M0129 (mini) ESCs out there. Like Vinny said, all of those ESCs have a blue status LED for each MCU.

If your ESC has a larger rectangular shape (as opposed to a square), it could be a really old ESC (Atmel-based, not STM32-based), which we do not really support any more. I hope this helps!

Alex

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.

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.

@John-Nomikos-0 , the ESC params / settings are completely separate from PX4. PX4 cannot modify the ESC params - all the ESC configuration is done through our tool voxl-esc. You should make sure the correct ESC params are installed before starting PX4.

PX4 just has the interface to control the ESC by sending the RPM commands to spin the motors.

Alex

@david-moro

If you look at this image, https://docs.modalai.com/M0169/#image-of-working-module it shows the TOF sensor (right) and the M0169 adapter (left).

The weight of the TOF module is 0.72g and weight of M0169 adapter is 0.93g.

This particular combo requires an external power input (4-5V as described here https://docs.modalai.com/M0169/#current-consumption). "External" in this case means additional power source besides the camera connector. The additional power input connects into M0169 via 2-pin JST connector.

The worse case power consumption is ~0.9W, which is a lot for such small module. The current draw plot shows a typical 5hz operation at maximum "exposure", which sends out 8 6-ms pulses of 1.0-1.1A (at 3.3V). so that is 1.1A * 3.3V * (5hz * 8 * 0.006s) = 0.87W. If you select 15Hz, the maximum exposure (emitter pulse time) will go down from 6ms to 2ms, so the maximum total power will remain the same.

This module would definitely require a heat spreader to operate continuously at this power. However maximum power output (even in auto exposure mode) can be limited to accommodate specific power dissipation capabilities. Additionally, the temperature of the emitter is reported from the TOF sensor.

Due to additional complexities that come with this new module (need for external power, which cannot be obtained from the camera connector) and heat management, we are working on the solution that would provide a positive user experience, so hence the delay.

I will check on the ETA

@ssansoy , you cannot access the data from these pipes directly, you have to use the MPA mechanisms to do that. There is an example of doing that for tflite detections right here : https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-mpa-tools/-/blob/master/tools/voxl-inspect-detections.c and the compiled app should also be present in the SDK, so you can run it on your VOXL2 (voxl-inspect-detections).

Alex

@robertociuch ,

I just built the sensormodules for ID 1 and 5. Please test it out. A while ago we did not have hires camera support in these camera slots, so the sensormodules were not built. Please let me know if that works for you.

Alex

https://storage.googleapis.com/modalai_public/temp/imx412_test_bins/20250430/com.qti.sensormodule.imx412_flip_1.bin

https://storage.googleapis.com/modalai_public/temp/imx412_test_bins/20250430/com.qti.sensormodule.imx412_flip_5.bin

@kestrelsystemsbp ,

Thank for clarifying. Indeed the camera-calibration app does not work well for high resolution camera calibration because the processing is not optimized for the large image size (takes too long to process a frame).

The workaround for now is to use down-scaled image for calibration. I will follow up with instructions for the easiest way to do this.

Alex

@h3robotics , I see, thanks for clarifying.

Is the ESC detected by PX4? What you can do is stop the px4 service using systemctl stop voxl-px4 and then run the px4 in a terminal : voxl-px4 -d , this will start px4 with an interactive px4 shell. You can also see debug prints from different modules that are starting up. Look for the voxl_esc module, it should say whether it was able to detect the ESC and, if so, then it will print some information about the ESC, such as its type, firmware version, etc.

If the ESC is not detected, then you may have ESC parameters set up for incorrect baud rate (your PX4 params expect 2mbit, but perhaps your ESC is using lower bit rate, so you can update your ESC params to 2mbit). It is possible that your ESC is using 250K baud rate which is what it may ship with, so you can try 250K in PX4 to test that. If your ESC is set up for the lower bit rate, i would suggest updating that to at least 921600, or 1mbit or 2mbit in order to reduce delay and support the throughput for the ESC commands and telemetry.

Alex

@Yoshimaru-Tanaka , you are right, the information in the documentation is not sufficient to diagnose this issue.

There is a page already for camera debugging information, but it is very brief. We will add more details (from this thread and more) to this page.

https://docs.modalai.com/debugging-camera-issues/

Thank you

Alex

@h3robotics , did you set VOXL_ESC_PUB_BST to 1? it should be a 0 or 1, not "Enabled". please double check.

@h3robotics , do you actually need to create a camera config, so that you can run voxl-configure-cameras or you just need to set up your system for testing a single camera? The latter can be done by modifying the /etc/modalai/voxl-camera-server.conf by removing all camera configs except for IMX412 (if you want to keep the same settings for IMX412). Also, depending on where you have the IMX412 / M0155 plugged in, you would use sensor module 0, 2, or 4 (corresponding to J6, J7 and J8) because the M0155 only exposes the single camera (lower) port on the dual-camera connector on VOXL2.

If you need more details, please let me know.

Alex

@kestrelsystemsbp , yes, alternate calibration methods are possible. Do you have a preferred method / software that you would like to use?

Also, which camera are you trying to calibrate and what resolution?

Alex

@Matthew-Wellner , I am glad you got it working! When you used M0076 single camera interposer connected to VOXL2 J7, actually you were connecting to the "lower" camera slot, so that would be J7L, meaning slot ID 2, not 3. That is why your camera was not detected in that case.

Regarding your M0084 not working, it could be a hardware issue in the flex cable or it's connectors. In order to figure this out, some more testing would be needed. Also, typically we suggest avoiding daisy chaining flex cables, so M0076 / M0135 allows you to do just that. It is possible that a combination of M0084 and another extension cable create sufficient signal distortion of the MIPI lines to cause CRC errors.

Alex

@KnightHawk06 ,

You should double check something - is your calibration pattern perfectly flat?

When I perform camera calibration, I use an LCD screen to display the pattern whenever possible, because the screes are typically very flat.

In order to avoid blurring, you could (temporarily) limit the upper end of the exposure range in volx-camera-server.conf to something like 5ms and that should help. This will cause the gain to be increased (automatically) to achieve the same i mage brightness, which will result in a bit more noise, but it should be ok. After calibration, you can set the upper exposure back. Alternatively, you can set the exposure / gain from voxl2 command line like so:

voxl-send-command tracking_down set_exp_gain 5.0 400

(this should override the automatic exposure / gain control and set the exposure to 5ms and gain to 400 (4.0x analog gain).

If you are still using the printed pattern, increasing the illumination in the room should also help make the image brighter and drive the exposure down, reducing the blur.

Alex