@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.

@tonygurney , I am assuming that you are using the ESC hardware version M0134 (you can confirm using voxl-esc scan tool.

Here is the datasheet for M0134.
https://docs.modalai.com/modal-esc-datasheet/

This ESC has an option (via installing a 0 ohm resistor) to provide 3.3V to pin 1 of J3. This is the same voltage that is used for the MCUs that run on the ESC and should be used with caution (if this voltage rail is brought down by overloading, the ESC will shut down). Please see image below that shows where 0 ohm resistor should be (carefully) installed to enable 3.3V on pin1 of J3 (marked in red)

If you actually wanted 5V (VAUX), that is available on the other side of the board via two test points at the edge of the board. This voltage rail is provided by a separate switching regulator. See the following section : https://docs.modalai.com/modal-esc-datasheet/#neopixel-led-support

If you REALLY need 5V to be present on pin1 of J3, then you can add a small wire jumper from the VAUX test point directly to the pin1 of J3 (which is marked with a white dot). This pin 1 of J3 is normally disconnected. Please only do this if you are comfortable performing this type of soldering and we cannot guarantee the results :).

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.

@sjt277 ,

The simplest approach is to use a separate USB-to-serial adapter for each ESC.

You can set up udev rules to map and distinguish the specific usb-to-serial adapters (using their unique serial numbers) to aliases in /dev/, such as /dev/esc0, /dev/esc1, etc.

Then run your testing using different USB devices to access each ESC (i am assuming you are using voxl-esc tools?).

For example, here is some relevant information: https://askubuntu.com/questions/49910/how-to-distinguish-between-identical-usb-to-serial-adapters

Does that help?

Alex

Hi @Matt69 ,

Yes, the shown ip address is a self-assigned address which happens if there is no ip address assigned by a DHCP server.

What wifi module are you using?

Does output of iwconfig wlan0 show that you are connected to your Access Point?

Alex

Hello @Tanner-Metzmeier,

We do not have a heat sink recommendation for VOXL2, however you can try off-the-shelf components, just be careful not apply excessive mechanical stress to the QRV5165 SIP while mounting the heat spreader to it (or removing it later).

Is there anything in particular that is causing VOXL2 to overheat (what type of processing)? We could try to help reduce the system load, if you provide more details on what you are actually running.

Alex

@Adnaan-Yunus , Thank you for reporting this. We will try to replicate the issue.

Do you have any more specific information that could help us? For example

• does rebooting VOXL2 allow you to connect from the same wifi client again (perhaps one time until it is cut off again)
• is there any way that you found to reset the wifi card to allow a new (previously seen) connection?
• have you tried setting the card to station mode and then back to softap mode?
• while the first client can no longer connect, can another client connect to the softap? I am wondering if the wifi card is still responsive or it does not accept any clients?

Thanks!

Alex

Hi @Jon-Brookshire ,

Please see the following post (just updated) : https://forum.modalai.com/topic/5052/starling-2-max-cad

Alex

Hello @Myles-Levine and All,

You have been very patient.. Sorry for the delay.

The Step file for the exact configuration you requested has been uploaded to our Assets page:

https://developer.modalai.com/asset/6

It should look something like (well, exactly like ) the rendering below. Please let me know if you have any issues with the model. It may take a few minutes to load..

Alex

Hi @jameskuesel ,

When you enable en_raw_preview, which is what we do when MISP is enabled, the preview_width and preview_height basically force the selection of a specific camera mode with those dimensions. This means that the camera will send a bayer image of that size.

After the image is received by the ISP (which does nothing else in RAW-only mode), then MISP consumes the raw bayer image and performs debayering on the GPU. Then misp_width and misp_height will be used to specify the dimensions of the output image, sampled from the original bayer image.

If the output dimensions have exactly the same ratio as the input dimensions, then MISP will perform (arbitrary) down-scaling only (no crop = same horizontal and vertical FOV). However, if the output dims have different aspect ratio, the output image will be a cropped (and downscaled) version of the original image, such that the width and height ratio is maintained (features are not stretched). The crop is selected to maximize the fit of the output image within the input image.

With that in mind, if you select 4040x3040 as preview resolution and select misp resolution such that both width and height are scaled by the same factor (does not have to be integer), you can calibrate the intrinsics using the small image and after the calibration you can upscale the intrinsics:

• multiply the principal point offsets by the same factor
• multiply the focal length by the same factor
• keep the same fisheye distortion coefficients (since they are a function of angle, not pixels)

See another version of this explanation in a different context : https://forum.modalai.com/topic/4900/running-qvio-on-a-hires-camera/12 (look for "intrinsics")

• Input to the EIS algorithm is the full bayer image that is defined by the preview_width and preview_height.
• the output image size is defined by misp_width and misp_height, just like when EIS is off. The misp resolution can be arbitrary
• an important parameter is misp_zoom, which defines the relationship between the original image and the output image, in terms of zoom level. if you set zoom = 1.0 with EIS enabled, then the misp output will produce the largest undistorted image that fits within the original bayer image
• there will be no deformation (stretching). the EIS ROI size will fit within the original bayer image and the zoom level is really controlling how much the FOV is reduced and how much stabilization margin you have.
• you can enable the ROI display (PIP or side-by-side) to see how the EIS ROI fits within the original full image
• the actual resolution of the misp output has nothing to do with how the EIS ROI fits within the original bayer image : the zoom value and fisheye undistortion dictate that. The output misp resolution just defines how many pixels the output image will contain, not the field of view (FOV).
• for output resolution, you can pick whatever you need for your application.

By the way, you can have multiple EIS outputs on the same camera concurrently (MISP supports up to 4 channels). So you can have one stream that is small resolution (for streaming over wifi) and another one higher resolution (and can be different aspect ratio) for high quality recording. https://docs.modalai.com/camera-video/electronic-image-stabilization/#using-eis-with-misp-channels

Please note that currently, when you use multiple misp channels from the same camera, the image is processed separately, meaning if you have a large resolution and small resolution misp stream, the small resolution is NOT generated by downsampling the output of the large stream (which could be a nice optimization, in some cases).

Please let me know if you have any other questions.

Alex

Hi @jon , do you always see the following warning right before the seg fault? (and never see it when there is no seg fault?)

@jon said in voxl-logger seg fault on shutdown:

WARNING, _stop_helper_and_remove_pipe timed out joining read thread

The way one would normally debug this is using gdb, but that would be tricky if you are spawning the logger from another (python) process and don't have a terminal to type in gdb (after crash) to investigate.. You could potentially attach gdb to an already running (spawned) logger.

Alex

Hi @qubotics-admin ,

Our understanding is that the voxl2_io driver should present itself as a generic PWM output (up to 8 channels) and you should be able to map any function you need to it. Although we have not explicitly tested every function. Can you please clarify which version of voxl-px4 you are using and elaborate on the "limited options" that you have for selecting the PWM function (what are you expecting to be able to set and what are the options).

Alex

@Piyush-Singh ,

Which TOF sensor do you have plugged into VOXL2 Mini (there are two options) and what is the camera type listed for the TOF entry in voxl-camera-server.conf? there may be a mismatch..

Config file TOF options are :

• pmd-tof for the (EOL) TOF V1 : https://docs.modalai.com/M0040/
• pmd-tof-liow2 for the new TOF V2 : https://docs.modalai.com/M0169/ (https://docs.modalai.com/M0178/) - two different variants that differ in the connector type that connects them to VOXL2

Alex