4 ms·
Fun idea and also I didn't know that websites could get access to my accelerometer data. However for me the sample frequency is 50 Hz which is way too low to me
by jmusall 5mo ago
Fun idea and also I didn't know that websites could get access to my accelerometer data. However for me the sample frequency is 50 Hz which is way too low to measure even the lowest string pitch (E2, about 82 Hz).
- hgomersall 5mo agoIf you know you have a single frequency close to an actual frequency of interest, you can use the fact you know you're in an aliased band to get a precise frequency estimate.
- jonathrg 5mo agoPresumably there is an antialiasing low pass filter somewhere before JS gets to the data. I have a similar sample rate and it certainly didn't work at all for me.
- ErroneousBosh 5mo agoIf the accelerometer samples at 50Hz, how could there be an antialiasing filter? What would that filter look like?
- colanderman 5mo agoAnything physical which dampens higher frequency oscillations would act as an antialiasing filter.
- ErroneousBosh 5mo agoWhat sort of size do you think something that would damp 25Hz vibrations in something that weighs a gram or two would need to be?
- regularfry 5mo agoThey have analogue AA filters just before the sampler.
- ckocagil 5mo agoaka a stroboscopic measurement, but I don't think it will work well for this case.
- KeplerBoy 5mo agoIt's just higher nyquist zones.
- superxpro12 5mo agoI guess thats sort of like a weird PLL thing? But I'd imagine you'd have to have prior knowledge of which string you're tuning otherwise the analysis is going to alias against every harmonic.
- regularfry 5mo agoEvery non-linear mixing of signals gives you sum and difference frequencies. It's less a weird PLL thing and more a weird trig function thing.
- kayson 5mo agoIts not even a non linear thing. Its a sampling thing. Even ideal sampling exhibits aliasing. https://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampling_theorem https://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampli...
- regularfry 5mo agoYes, and. You can look at aliasing as a special case of heterodyning. Sampling is a nonlinear mixing.
- peheje 5mo agohttps://sinceyouarrived.world/taken https://sinceyouarrived.world/taken
- lightedman 5mo ago"the lowest string pitch (E2, about 82 Hz)." My 6-string Kiesel Kyber bass would like a word with you while it sounds 41Hz.
- ta2112 5mo agoI guess the low B should be about 31Hz