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sensor selection for velocity measurement
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sensor selection for velocity measurement

by Mhemling33 on Sun Jun 13, 2021 9:50 pm

I am trying to setup a project similar to the https://learn.adafruit.com/toy-car-speed-timer, but utilizing something like a photoreflective laser sensor. I am measuring exit velocity of a baseball in a controlled environment, so break beam would greatly increase setup complexity. The other issue is that it needs to have a response time of 1ms or less.

I am open to other sensor suggestions, things i have tried without success.

ultrasonic
IR Reflective sensor
TOF sensors
Microwave Doppler Sensor

Really banging my head against the wall with this one, any help is greatly appreciated.

Mhemling33
 
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Re: sensor selection for velocity measurement

by mikeysklar on Mon Jun 14, 2021 8:16 pm

How close will you be able to place the sensor to the baseball at its exit point?

My initial thought would be to go for the VL53L0x LIDAR, but you need to be within 4' and it will be nowhere near 1ms.

https://learn.adafruit.com/adafruit-vl5 ... t?view=all

Maybe it is worth hacking an existing radar gun that has a TTL serial interface? That make things easier in that they start @ $55 and are pre-calibrated to +/- 1 mph.

Another option would be to place multiple inexpensive motion sensors at precise distance and determine the velocity.

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Re: sensor selection for velocity measurement

by adafruit_support_bill on Mon Jun 14, 2021 8:30 pm

Another option might be to use a camera. Assuming the camera is at a known distance and oriented orthogonal to the direction of travel, you could derive the velocity from the distance traveled between successive frames.

Using multiple synchronized cameras and some trigonometry, you would have more flexibility in your setup.

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Please be positive and constructive with your questions and comments.