Collision TOF Sensor

[Chaitanya_Butta]

Dear sir/madam,

I am using the VL53L7CXV0GC/1 ToF sensor, and my main goal is to stop the motion immediately when the sensor detects an object. However, the sensor is taking too much time to detect the object, due to which my device is colliding with it. I need to overcome this delay issue.

I have already tried increasing the frequency and timing settings, but the delay still exists.

Currently, I am using the sensor in 8x8 resolution mode. I want the sensor to detect objects only when they appear exactly in the center area of the sensor’s field of view. I tried ignoring the top zones (Zone 1 to Zone 48), but the sensor is still detecting objects from those ignored zones.

To solve this, I selected only the center zones: 26, 27, 28, 35, 36, 37, 43, 44, and 45. Although the sensor is now detecting objects mainly in the center area, the detection is still slow, and the device is hitting the object before stopping.

Please provide a solution as soon as possible.

Thanks, and regards,

Chaitanya B

[Bin]

Hi:

Could you describe this use case in more detail? What is the maximum test distance for collision avoidance?

Usually, we can set the frequency to 100 Hz at 4x4 resolution for improving the sensitive, but this will shorten the sensor’s maximum distance.

Regarding to only use the central areas (26, 27, 28, 35, 36, 37, 43, 44, and 45). As far as I known, the VL53L7CX does not have an API. By default, all zones are measured and the corresponding results are output. I’m curious how you set this up—did you simply filter out the unselected zone information in the upper-layer application?

Additionally, I’d like to let you know that we do have a fast-ranging solution, but due to confidentiality reasons it is only available for specific projects; please understand. If you have a specific project, please contact ST FAE to obtain this solution.

Best Regards,

Bin FAN

[Chaitanya_Butta]

Thank you for your response.

I am using this sensor in a medical device application where the X-ray tube is moving. If any object is detected within the collision range, I need to stop the motion immediately. Since this is a safety-related application, fast and reliable detection is very important.

My required collision detection range is only 1 cm to 40 cm, and the maximum operating distance requirement is around 50 cm, which is much lower than the maximum distance specified in the datasheet.

I understand that all zones are measured by default. In my implementation, I am filtering out the unwanted zones in the upper-layer application and considering only the selected zones (26, 27, 28, 35, 36, 37, 43, 44, and 45) for collision detection. If any object appears within these selected zones, I treat it as a collision condition and stop the motion.

You mentioned that 4x4 resolution with 100 Hz frequency can improve sensitivity. Could you please confirm whether this configuration is recommended for short-range collision avoidance applications like ours? Also, if there are any recommended parameter settings or best practices for improving response time and stability, please let me know.

Additionally, regarding the fast-ranging solution you mentioned, kindly guide me on how we can proceed further through the ST FAE for evaluation in our project.

Looking forward to your guidance.

[Bin]

Hi:

I have already forwarded your request to our FAE, and he will contact you as soon as possible to follow up with you directly.

Thank you for your patience.

Best Regards,

Bin FAN

[Chaitanya_Butta]

Thank for your response and time.

[Chihming]

Hi,

Thanks for your interest in VL53L7CX.

The sensor spec is as the below:

*FOV: 60° x 60° square field of view,

*Ranging speed: 60Hz for normal

*Max ranging distance up to 350cm

*Min ranging distance from 2cm

*Emitter light: 940nm invisible light

*Multizone ranging output: 4x4 or 8x8 separate zones

The fast-ranging mode should be shared the customer with NDA. Please check the NDA with ST marketing team. 

BTW, could you let us know what the platform you connect with TOF sensor? Like STM32F401?

Best Regards,

Chihming HUANG

[Chaitanya_Butta]

Hello,

Thank you for your support.

Could you please let me know the expected response time of this device for object detection?

I am currently using the sensor with the STM32C091FCP6 MCU. In my application, the sensor is mounted on a moving system, and whenever an object is detected, the motion must stop immediately to avoid collision. However, I have observed that the sensor is taking more time to detect the object, due to which the device is colliding before the motion can stop.

Since this is a medical device application, reliable and fast collision detection is very important for us.

Could you please suggest:

• Recommended settings for reducing detection latency
• Whether 4x4 resolution and 100 Hz mode would improve the response time
• Any best practices for fast and stable collision detection in short-range applications

Also, regarding the fast-ranging mode you mentioned earlier, could you please guide me on how to contact the ST marketing team or ST FAE team to evaluate this solution for our project?

Looking forward to your guidance and support.

Thanks, and regards

Chaitanya B