@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 ,

I believe you are correct! Thank you. We will double check this and fix.

@John-Nomikos , I think something is off with your setup, because even the small encoded stream cannot achieve 30fps. I just did a quick test on my voxl2, able to maintain 30fps in this stress test.

Something is bogging down the system, you should look at output of top to see if there is some other process that is using up a lot of cpu.

If you cannot figure out the cause, please any other info that might help about your setup, anything non-standard that you might be using in voxl-camera-server.

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.

@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.

@Prabhav-Gupta , yes it seems like OpenCV and ROS YUV_NV12 formats do not match up. I will take a look at it.. it seems the ROS YUV is packed (interleaved) while standard for storing YUV NV12 is having two planes : plane 1 : Y (size: widthheight), plane 2 : UV (size: widthheight/2)

In the meantime.. you can stream a rtsp h264/h265 from VOXL (use decent quality so that image looks good) and use opencv to receive the stream and get decompressed images: https://stackoverflow.com/questions/40875846/capturing-rtsp-camera-using-opencv-python

Would that work for you ? (unfortunately with rtsp stream, you will not get the full image metadata, like exposure, gain, timestamp, etc).

RTSP streaming can be done using voxl-streamer, which can accept either a YUV (and encode it) or already encoded h264/5 stream from voxl-camera-server.

Alex

Hi

If you are looking for more low level functionality and a bit easier to experiment with, you may want to check out https://gitlab.com/voxl-public/utilities/voxl-rtsp/-/tree/dev . This tool is good for testing or running simple scenarios. This tool accepts some commands (like exposure control) via command line, so you could add a simple feature to save an image upon a command line input. Please see README to see how the exposure control input works and code for how it's implemented.

Please make sure that voxl-camera-server is disabled when you run voxl-rtsp.

If you still would like to go through the voxl-camera-server approach, we may need some more input from respective devs :).

I hope this helps..

Alex

@ashley-miller , for this motor (28xx class), you should use the following ESC M0138 FPV ESC :

https://www.modalai.com/products/m0138
https://docs.modalai.com/voxl-fpv-esc-datasheet/

The mini ESC (M0129) is designed for small and lightweight drones and mini FPV racers (750g or less for slow flyers and 500g or less for mini FPV drones).

The peak power for one of these motor is almost 1kW each - the mini ESC cannot handle that for several reasons, such as peak current capacity, thermal.

If you would like to use the 2808 motor, please choose the M0138 FPV ESC and perform motor calibration using voxl-esc tools : https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/blob/master/voxl-esc-tools/calibration.md

Also, please review the following FAQ: https://docs.modalai.com/voxl-escs/faq/

Alex

@jeremyrbrown5 , it is possible that overheating VOXL2 cpu could be causing your SoftAP performance slowdown. You can run voxl-inspect-cpu which is a tool that will show you cpu usage, temps and other stats. If the CPU cores reach 95 deg C, the thermal management will slow down the cpu clock, so all the processes will run slower, including SoftAP.

Alex

Hi @SKA ,

I believe i fixed this issue with full-follow mode in the camera server. Now EIS has a body->imu transform, which is read from the extrinsics file and is used to properly rotate the image, instead of hi-jacking the cam->cam_eis transform.

So now your cam->cam_eis transform should work. Please make sure the imu_apps->cam transform is correct, if your camera is rotated 90 degrees.

Please check the commits from Nov 10 : https://gitlab.com/voxl-public/voxl-sdk/services/voxl-camera-server/-/commits/dev

Alex

Hello @jeremyrbrown5 ,

Can you please answer the following questions to help us diagnose the issue?

• Which wifi adapter are you using?
• Does rebooting VOXL2 Mini help?
• How are you measuring the connection quality?

Alex

Also, a quick note.. regarding what preview resolution to use with IMX412 camera with MISP enabled..

For best quality (non-EIS applications, where the output is 16:9 aspect ratio, such as 3840x2160, 1920x1080, 1280x720), you should select 3840x2160 as the preview resolution. For EIS applications, the full frame 4040x3040 resolution should be used because it will allow more stabilization margin. selecting 3840x2160 will tell the camera to crop this region from the full frame 4040x3040, since we don't need the rest of the image.

For low latency applications, you can use input resolution of 1936x1080. Note that this is slightly non-standard (as opposed to 1920x1080 because the 1936x1080 resolution allows faster processing. So you could have input resolution of 1936x1080 and output resolution of 1920x1080, 1280x720, etc.

Alex

@Jetson-Nano , this question is probably for @Eric-Katzfey

@Jetson-Nano , it seems that Vertiq has PX4 support, so you should be able to modify their driver to enable the turtle mode. The mode is triggered by checking the RC switch within the voxl-esc driver.

https://iqmotion.readthedocs.io/en/latest/tutorials/ifci_px4_flight_controller.html

If you disable the voxl-esc driver, PX4 should work fine, as long as you correctly update the PX4 parameters to use another ESC type.

Alex

@dirizarry ,

If your lens does not have an IR filter, the colors will be distorted. Please take a look at sample images : https://docs.modalai.com/M0161/#image-samples-for-sensor

You could replace the lens with another lens that has an IR filter.

If you do want to keep the lens without IR filter, please follow the steps below.

My best suggestion is to download the latest IMX412 drivers from here

Extract the archive and select the sensormodule with the correct id (matching the ID that you have already been using). back up existing imx412 sensormodules and copy the new one to /usr/lib/camera/

Then, edit /etc/modalai/voxl-camera-server.conf - i will just provide a minimal config for a single IMX412 camera (you will need to check the camera id in the config file). If you use voxl-portal, you should be able to see hires_misp_color and h264 encoded stream hires_misp_encoded.

{
    "version":  0.1,
    "fsync_en": true,
    "fsync_gpio":   109,
    "cameras":  [
    {
        "type":             "imx412",
        "name":             "hires",
        "enabled":          true,
        "camera_id":        0,
        "fps":              30,
        "en_preview":       true,
        "en_raw_preview":   true,
        "en_misp":          true,

        "preview_width":    3840,
        "preview_height":   2160,
        "misp_width":       1920,
        "misp_height":      1080,

        "misp_zoom":        1,
        "misp_gamma":       1,
        "misp_awb":         "auto",
        "ae_mode":          "lme_msv",
        "gain_min":         100,
        "gain_max":         32000,
        "ae_desired_msv":   100,

        "misp_venc_enable": true,
        "misp_venc_mode":   "h264",
        "misp_venc_br_ctrl":"cbr",
        "misp_venc_mbps":   5,

        "en_small_video":   false,
        "en_large_video":   false,
        "en_snapshot":      false
        }
    ]
}

Please note that after you start voxl-camera-server, the config file will be auto-populated with some more default parameters for this camera.

When viewing hires_misp_color stream in voxl-portal, if you see any flickering, please try to set voxl2 cpu mode to perf : voxl-set-cpu-mode perf as well as reduce the jpeg quality that is used to display this stream (which is YUV converted to jpeg in the back-end). The mjpeg quality can be changed by enabling the advanced controls in voxl-portal (click the tiny check box in the bottom left corner of the page) and reduce the Quality slider.

Using MISP should help with reducing the IR effects, but it won't be perfect due to really strong IR light that can be present durig day time outdoors.

Alex

@aheyne ,

Sorry for the delay.

You can find the M0172 CAD file here

Alex

@jimbow77 , regarding #4, there are four batteries (two sets).

#3 - we don't have an option to install FLIR Lepton, but you can purchase it separately (from another vendor) and install it. The adapter is present in Starling 2 Max, so you would just need to install the Lepton sensor into the socket.

Alex