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Topic starter
2025-09-07 11:36 am
Hi - I am new here,
I would like to build a DIY golf ball 3d motion tracker.
My tracker project plan is stationary with 3 sensors and a golf ball will be hit(launched) to pass through the sensors (avoiding interference from the club).
I found the HC-SR04 video from here very helpful - provides guidance on many topics I need.
If my computations are correct, given a max range distance of about 12 feet, a minimum of 2 sets of (x,y,z) distance for speed calculation; results in a max recordable golf ball speed about 70mph.
Can the sensor frequency be adjusted to allow parallel transmission, eliminate waiting for each (x,y,z) sensor to return ? This would allow more points recorded, for better/faster speed calculations.
Thanks, Allen
2025-09-08 3:57 am
Can the sensor frequency be adjusted to allow parallel transmission, eliminate waiting for each (x,y,z) sensor to return ?
I don't think it's possible to alter the pulse frequency (40KHz) and even if you could, it wouldn't affect the speed of the pulse. A 40KHz pulse and a 100KHz pulse travel at the same speed. The data sheet says that you need ~47ms for each sample. You want to do three samples. You might be able to overlap them to reduce the per sample time, but that would be unreliable, IMHO. FWIW, I'm still struggling to get accurate measurements up to 70cm; After that it looks like random noise. I confess I can't imagine your test geometry (where the sensors are placed) or how to coordinate them. I don't think a sonar sensor has the responsiveness that is required.
The one who has the most fun, wins!
Topic starter
2025-09-09 12:04 pm
thank you very much for the info.
The idea on changing frequency would allow 3 pulses/readings at once, each axis. I don't have to wait for the x axis reading then the y axis reading, then the z axis reading. The sound pulse speed is not so much a factor, but allowing 3 simultaneous measurements.
My thought was 3 sensors, 2 a few feet apart horizontally to get horizontal measurements, directions, #3 a few feet above to get the vertical measurements, then triangulate further computations. I was curious about accuracy, but if the accuracy diminishes greatly over a few feet, my "triangulation computations" might end up with a tolerance of +/- 50mph 🙂 🙂 🙂
Thanks, Allen
2025-09-09 10:13 pm
Hi Allen,
I would like to build a DIY golf ball 3d motion tracker.
I’m curious about how you plan to trigger the sensors to catch the flight of the ball? Would an IR emitter/receiver pair be used as a break beam sensor? Something like a garage door IR beam. The ball passing through that would then start the trigger signals to the ultra sonic sensors?
Tom
To err is human.
To really foul up, use a computer.
Topic starter
2025-09-10 6:37 pm
Tom, thanks !
.... umm good question - didn't work out the start, stop portion yet.
Since it's stationary capturing one golf stroke at a time, so far a few possibilities exist.
- Trigger the start/stop with a remote or on/off switch.
- Let the process stay on for duration of operation/testing, the sensors send a timeout result back if nothing recorded. I haven't worked out if any issues yet for possible interference with this.
Thank you for the input ! ... more portions to plan out 🙂
Allen