Sample Rate ADW Teensy 4.1

[Peterschnecke]

Hi,

I have a question regarding the possible sampling rate of the ADW of the Teensy 4.1.
Is it possible to sample the ADW with 100k Hz or even better 200k Hz?

I want to build a measuring device to measure the muzzle velocity of a 6mm steel ball, which is accelerated with compressed air. For this purpose, two photodiodes are to be mounted in the barrel at a distance of 150mm. The targeted velocity is 80m/s.
If I have calculated correctly, a 6mm steel ball results in an overlap time of 7.5µs per sensor. So I would have to sample somewhere in the range of 200k Hz to be able to make a reliable statement.
I would like to use the Teensyduino programming interface.

Is this possible with the teensy 4.1?

I found an old thread talking about the sampling rate of the ADW on a Teensy 3.1, but there it is about the audio library and 44.1kHz
https://forum.pjrc.com/threads/29645-What-is-the-Sampling-Rate-for-ADC

Thanks

 

[joepasquariello]

Is it possible to sample the ADW with 100k Hz or even better 200k Hz?

Do you mean the ADC? Rather than sample at a high rate, have you considered directly measuring the time between the on/off transitions that will occur when the ball blocks the light path? If you create a digital signal from the output of the photodiode, you could connect that to one of the Teensy 4 hardware timers and use the input capture function to accurately measure the times between signal on/off/on. If you can measure that time, then velocity = distance/time. Take a look at the FreqMeasureMulti library and run the examples to get an idea of what it can do

 

[Peterschnecke]

Do you mean the ADC?

Yes, I do. I'm sorry, english is not my native language and ADW is the german abbreviation for ADC.

Rather than sample at a high rate, have you considered directly measuring the time between the on/off transitions that will occur when the ball blocks the light path?

I have not. So far I have only done a small handful of projects with an arduino nano. So I'm still a beginner and I'm open for any kind of tips.
I will read into that.