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  1. When using averaging. Is it possible to average...

    When using averaging. Is it possible to average using floating point math into a float or double variable?

    Also is it possible in stead of averaging to use median?

    I could do it in my program...
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    HmmmÖ is this something one could test? I have a...

    HmmmÖ is this something one could test? I have a few spare teensies.
  3. Yes that is a good suggestion :)

    Yes that is a good suggestion :)
  4. I will start with just having one drum...

    I will start with just having one drum interfacing with an app on the PC and go from there.

    Thanks for that link, I think hid is the way to go. You just saved me a ton of time.
  5. That sounds logical. This is great info, I will...

    That sounds logical. This is great info, I will look into CAN bus. I know that the edrumin which is a teensy based drum module uses something called HID to send data for the monitoring of waveforms...
  6. Thanks, I have gotten great reactions from people...

    Thanks, I have gotten great reactions from people so far which is encouraging when you have been working hard on something. The difficulty is really to differentiate the cross sticks from the rest....
  7. Iíve been making this project for about 2 years,...

    Iíve been making this project for about 2 years, so a lot of effort has gone into it and I have learned to program from scratch with no prior knowledge to do it. It is not some half assed attempt.
    ...
  8. It would be A LOT less cables if you can connect...

    It would be A LOT less cables if you can connect them in series. Itís sort of a big deal in edrumming to get rid of the cables.

    How long cables can you use? The laptop is usually a meter from the...
  9. Was this a stupid question?

    Was this a stupid question?
  10. How many teensy 4 can be connected together?

    Hello!

    Iím doing an electronic drum project where I have a teensy 4 inside a drum doing all the sensor processing and MIDI triggering. It sends out midi through a usb cable to a pc that triggers...
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    Yeah I also think it has to do with the...

    Yeah I also think it has to do with the separation of analog and digital components. The T3.6 has analog ground which the T4 doesnít have. I think paul said it wasnít possible to separate them.
    ...
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    Iíd like a teensy 4 with good quality analog...

    Iíd like a teensy 4 with good quality analog inputs. Right now they are quite noisy.
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    Great detective work done by yeahtuna. Is this...

    Great detective work done by yeahtuna. Is this change with usb_midi_flush already implemented or is this something Iíd have to change manually somewhere? Iím guessing itís somewhere in the midi...
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    Thanks. I know but I need to discard all values...

    Thanks. I know but I need to discard all values and start over if a condition is met
  15. How fast are you reading the 3.6? I seem to be...

    How fast are you reading the 3.6? I seem to be able to read the 4.0 at 2MHz. With 4 averages I can get 50kHz for 10 piezos. Of course at 12 bits the noise level with 4 averages is at +/- 4 on a...
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    What is the difference between the mean and...

    What is the difference between the mean and average functions?

    I need a running window giving me the average of the values currently inside the window. If I empty the buffer and start filling with...
  17. I have noticed something similar on analogreads...

    I have noticed something similar on analogreads where the noise will double ocassionally. I can solve it by recompiling and adding a small change in the code. It could be anything, like adding...
  18. Paul this is exactly how I've thought about...

    Paul this is exactly how I've thought about solvning it. I just have to check the 10 timers I have for this from time to time and if it's too large reset it to a value that's above what my program...
  19. Yeah I guess Iíll have to do something like that....

    Yeah I guess Iíll have to do something like that. Thanks.
  20. So what happens if something occurs at 990, it...

    So what happens if something occurs at 990, it starts over at 1000 and then nothing happens until it starts over again and then I check and itís at say 10? The time will still be 20 but 1020 has...
  21. Iím extra slow today. I understand now. I didnít...

    Iím extra slow today. I understand now. I didnít consider that a negative value will be represented differently with an unsigned integer.

    So if the time when something happens is 990 and it starts...
  22. This is what Iím doing: I reset the timer to zero...

    This is what Iím doing: I reset the timer to zero when an analog AC value crosses zero. Then if the signal crosses a threshold I check how long ago the signal crossed zero.

    If there hasnít been a...
  23. This is what Iím doing now and what I meant by...

    This is what Iím doing now and what I meant by starting a timer. I reset the timer to zero.
  24. ElapsedMicros/millis, how to avoid overflowing

    Hello!

    In stead of me trying to solve this on my own doing something unnecessary and inefficient, I figured Iíd ask here first because Iím sure itís a common problem.

    Iím starting a counter of...
  25. Oh, that looks very neat. I'll try something...

    Oh, that looks very neat. I'll try something similar.

    I can't do the for loop though, I will need to read two sensors at a time and do all the work on the previous sensor pair while waiting for...
  26. General C++ coding program structure guidance

    I learned some programming in C++ and I've started working on a project. I have difficulties getting started with the coding because of some problems with structuring the program.

    I have 10...
  27. I noticed something else. I connected a sensor...

    I noticed something else. I connected a sensor that I deliberately used a much longer cable so it picks up 60 Hz mains hum, you can see the 60Hz oscillation clearly. When it's misbehaving the 60Hz...
  28. Yeah I figured it would be something like that....

    Yeah I figured it would be something like that. It seems to not be consistent. It doesn't matter which two analog inputs I read simultaneously. If I get noisy signals I just have to recompile a few...
  29. Yes same configuration on both channels. The...

    Yes same configuration on both channels. The signal I showed is low pass filtered in software. It is a 1.25V DC signal from a voltage reference although you are seeing it as 0. I didn't take a...
  30. No the different speeds is a typo. I'm usig the...

    No the different speeds is a typo. I'm usig the same speeds.

    It's an SMT board which I designed to the best of my ability. I'm not dissatisfied with the noise I just want it to be consistent.
    ...
  31. I'm using a teensy 4.0. Is there a reason why I'm...

    I'm using a teensy 4.0. Is there a reason why I'm getting twice the noise if I choose to read certain combinations of analog inputs simultaneously? I'm not quite sure what's going on, I'm reading all...
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    I have now switched to using a voltage reference...

    I have now switched to using a voltage reference and I have a question about overvoltage protection.

    The op amp inputs in my circuit are protected with resistors so there should be no currents...
  33. Thanks for clearing this up. So Cas is the...

    Thanks for clearing this up.
    So Cas is the external circuit capacitance and is not part of the adc circuit?

    For some reason I didnít see Cadin, would have been much easier.

    I guess I will have...
  34. Iíve done exactly that. Iíve pretty much sweeped...

    Iíve done exactly that. Iíve pretty much sweeped the filter from 2k to 500k. What improves things drastically is filtering in software using floats and doubles. RC filter seems a waste of board...
  35. Iíve already tested an RC filter. Iím not sure if...

    Iíve already tested an RC filter. Iím not sure if itís making any difference or if itís worse. I see no point to be honest.

    Software filtering makes a huge impact indeed.
  36. Would that antialiasing filter be below half the...

    Would that antialiasing filter be below half the frequency of the sample rate for each sensor or the sample rate of each ADC? Half of 50kHz or 250kHz?

    Or would that also include the averaging for...
  37. I'll take a look at it although I'm not sure it's...

    I'll take a look at it although I'm not sure it's going to apply.

    What I really want to find out is the acquisition time of the teensy adc (how long it charges the internal capacitor) and the size...
  38. You are talking about the exact thing that the...

    You are talking about the exact thing that the youtube link above shows. They show how to calculate these things. Only problem is knowing what values to put in from the op amp and adc datasheets....
  39. Of course, I oversample and use a software filter...

    Of course, I oversample and use a software filter but it seems that averaging on the ADC settings gives better results compared to oversampling and filtering in software. This seems to me that there...
  40. I'm not sure if you or I am misunderstanding....

    I'm not sure if you or I am misunderstanding. Sampling multiple times is what the averaging setting in the ADC does, does it not? You can choose 2, 4, 8 or 16 averages I think. It is the most...
  41. Maybe I'm missing something here but say I'm...

    Maybe I'm missing something here but say I'm sampling 10 sensors at 50kHz each at 12bit. Every sample is averaged 4 times so it's actually 200kHz per sensor. 10 sensors with two adc's means each ADC...
  42. Suitable op amp for driving the teensy4 ADC

    Hello!

    I just saw this document: https://www.eetimes.com/using-op-amps-with-data-converters-part-1/#

    Part 2: https://www.eetimes.com/using-op-amps-with-data-converters-part-2/

    Part 3:...
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    The Texas Instruments manual for some reason...

    The Texas Instruments manual for some reason showed the pins from upside down view. Voltage reference is working now.

    However the problem was not the voltage reference or the circuit. Basically I...
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    Ok, so I got a voltage reference in the mail, the...

    Ok, so I got a voltage reference in the mail, the LM385Z...
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    Ok thanks. How exactly do you calculate how many...

    Ok thanks. How exactly do you calculate how many bits? I'm guessing it should be dividing the max value with the noise value and then if it's about 1024 it's 10 bits.
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    How could I see what the noise floor of the...

    How could I see what the noise floor of the teensy is and not interference from my circuit?
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    Nope, that made no noticeable difference. Neither...

    Nope, that made no noticeable difference. Neither did pulldown.

    I loaded up a fresh teensy4 without any circuit. Just sampling the empty analog pin has more noise than my circuit. Why is that.
    ...
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    I will have to test. Iím designing a new pcb with...

    I will have to test. Iím designing a new pcb with only surface mount components and itís much smaller so all loops should be smaller. Will see if there is any difference. Star grounding seems pretty...
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    When designing a PCB that the teensy4 gets...

    When designing a PCB that the teensy4 gets soldered onto, should I leave the unused pins unconnected? Iím only using the ADC pins and 3.3v/ground pins.

    I only use one ground pin and Iím not sure...
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    Yes but the piezo voltage is more like -10 to...

    Yes but the piezo voltage is more like -10 to +10v around vcc/2 so it might give me 0-3.3v i to the op amp.

    Also it seems you control the voltage swing with the resistor in series with the diodes....
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