Has anyone successfully made a doppler radar for measuring bullet speeds using hb100?
>>2957765No, but I made a light sensor for measuring airgun bullet speeds that attaches to the barrel. 2 pairs of 2 IR LEDs at fixed distance, microcontroller on interrupts measures timing, calculates speed.
OP here. that's quite simple but not challenging enough people have used PC sound card for that too, just an op amp, few IR leds and two photodiodes
>>2957765You need to calculate the frequency range for the proposed bullet speeds then bandpass filter and amplifier. Most likely you can filter this out of whole rubbish.
>>2958299Also you'll have to open that box to get behind comparator BC iirc those shitty motion detectors output a meander for the most massive moving object. That wouldn't do . take the signal right from the mixer, filter the needful and perhaps that'll do.
>>2957765did you ask chatgpt? i asked it something about your idea and this is what I got.Yes — you *can* write code for the cheap Doppler radar motion modules (like the **HB100**, **RCWL-0516**, or **CDM324**) to measure BB or pellet velocities… **BUT** you need to understand their limits first.Below is a breakdown of what works, what doesn’t, and an example of how you *could* build a small Doppler-based FPS meter.and it spit out a bunch of code, you should ask it if you haven't
I guess, the only way is to know is to try and make it.>>2959892code is provided by manufacturers...What problem here is, is it capable in reading signals reflecting off of such small object?
I remember reading somewhere of somebody making a bullet speed device by using 4 sheets of aluminum foil and a device that can measure the voltage or maybe it was ohms.So 2 sets of aluminum foil sheet; each set a distance apart and noted, and each set has the aluminum foil sheets like .125" away from each other.When the bullet hits the first set of aluminum foil there is now voltage passing from sheet 1 to sheet 2.And a few milliseconds or whatever the same exact thing happens to the second set of sheets.A little math happens using the recorded time and the known distance between the sheets and you have your speed.The sheets can usually be fired at several times before they disintegrate, and calibration is done by having both sets of sheets as close as possible and recording the offset.
Yes, can be easily done...have a high frequency square wave source, have pulse counter that has a trigger for starting the count and stopping it and connect those triggers to the plates and count pulses.by that point, i'd rather use stereo recording-PC sound card and place mic at muzzle and other at target
found it.
>>2967008obviously needs mods (change the oscillator with the trigger part, add more digit and speed calc will still be manual (unless you use microcontroller)
