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  1. E

    Display options with minimal switching noise ?

    Thanks for the comment. I think I am going to do it the old fashioned way : two 7-Segments leds.
  2. E

    Display options with minimal switching noise ?

    Hello, I have made a bunch of synths, and I always had to struggle when using small displays, like small OLED display (128 x 64 I2C) or TM1637 7-segments displays. These displays use charge pumps and induce a lot of switching noise. I manage to get rid off the major part of this noise with...
  3. E

    how to access a specific data byte on SD card ?

    Thank you so much Paul, this is exactly the information I was looking for. I take the occasion of this thread to to say how much I appreciate Teensy chips and the community. Amazing work, amazing people ! Emmanuel
  4. E

    how to access a specific data byte on SD card ?

    Hello, I have made a MIDI controller and want to save some presets on SD card. I used to do this with EEPROM. But I have too much data so I want to store data on SD card. I use a T3.6. I can write and read my data on SD card but I can't figure out a way to retrieve data at a specific address...
  5. E

    adding velocity to synth but keep envelope release

    Hello, I have made quite a few synths with velocity. First, I do my own FSRs using velostat. It is very cheap, and much more sensitive. Here is my overall process. Use envelopes, don't use amplitude. Trigering notes : if FSR output > threshold + debounce -> envelope.noteOn() if FSR output <...
  6. E

    Monophonic Guitar Synthesizer with subtractive synthesis

    Hello, My name is Emmanuel. I made a few years a go this little box, using the AudioAnalyzeNoteFrequency object from the audio library : https://www.pjrc.com/wooblizer-acoustic-note-to-wave-synthesizer/ I had good results, but I need to get lower latency. In a post, Wolke mentioned : "colin...
  7. E

    ideas for pressure sensitive sensors ?

    Thank you for the explanation. It gives me ideas : - note "touch" detection with capacitive key (a metallic washer) - pressure detection with cheap velostat under every washer I made a quick test : it works well. Velocity response is far from linear. I must make an array to match readings with...
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    ideas for pressure sensitive sensors ?

    Thanks for the suggestion. I have tested piezo sensors. Unfortunately, it doesn't work very well. They do a good job to detect a "hit". But it is tricky to detect e "release". They also fail to measure velocity with enough accuracy. It's OK for impacts (like drum sensors), but it doesn't work...
  9. E

    ideas for pressure sensitive sensors ?

    Hello, I am looking for fresh ideas to make a keyboard with pressure sensitive sensors. Here are what I would like to get : -> high sensitivity. A very light finger touch must trigger a note. -> fast response (low rise time) -> simple mechanism I have tried different things so far : ->...
  10. E

    phase modulation + vibrato

    Hello, I have asked this question before, but I am still stuck wit this problem. I would like to use phase modulation and frequency modulation at the same time. I want to use phase modulation to create complex waveforms, and frequency modulation for vibrato effect. But the...
  11. E

    which display for audio projects ? Oled, TM1637, LCD...

    Hello, I have made a few Teensy synthesisers. Almost every time, I had a hard time isolating digital noise from audio signal. I try to follow basic rules about decoupling and PCB design. But I am not an expert and this is a difficult art... I have noticed that displays induce a lot of noise. I...
  12. E

    [queued] MiniTouch : low cost T3.2 synth for children workshops

    Hi, Here is the new MonoiTouch 2nd edition ! Emmanuel
  13. E

    MiniTouch 2nd edition, T4.0 compact synth

    Hello, Here is the 2nd edition of the MiniTouch, a compact and affordable stand alone synthesiser. I focused on musicality, portability, and fun. Here are the main features : - capacitive 18 notes builtin keyboard - builtin small speaker, battery - line + headphones output - 16 pots (32...
  14. E

    Mixer with more than 4 channels

    You are wright, it would help. I know there is this incredible tools, but I have never succeed making it work for me : https://manicken.github.io There is an "ultimate mixer". Don't know more about it... Emmanuel
  15. E

    Buying Simple Teensy-based Synthesizer

    Hello, I do simple to complex teensy based synths. Have a cool there : https://www.youtube.com/watch?v=RrDzcaljXUk and there : https://www.youtube.com/watch?v=tW7UIrEDZno If you can me more precise of the kind of tool you would like ti build, I am pretty sure a lot of people could help you...
  16. E

    filter cut off frequency and keyboard tracking

    Bonjour et merci ! this formula new_FC = note_freq * track where : track = n unfortunately doesn't work. It cut low pitch notes too much : with track = 4 for C = 162 Hz -> new_FC = 648 a lot of harmonics are cut. Sound is rather dull. for A = 880 Hz -> new_FC = 3520 not...
  17. E

    filter cut off frequency and keyboard tracking

    Good morning ! (from France !) Well the code is very long, because of the polyphony management of my synth. I think we can really focus on the core equation that links Note Frequency with Cut Filter Frequency. Say we have : - a LP filter, defined with its cut frequency "centered_FC" - the...
  18. E

    filter cut off frequency and keyboard tracking

    Complete code is very long... I will send a more detailed version tomorrow. Thanks for your help, I appreciate.
  19. E

    filter cut off frequency and keyboard tracking

    Here is an example of what I have tried : filter1[myActiveVoice]->frequency(osc1_frequency[myVoice] + osc1_frequency[myVoice]*Fc_ratio); Fc_ration is contrôle by a midi controller. I tried different ranges, but it doesn't give an even effect.
  20. E

    filter cut off frequency and keyboard tracking

    Yes, this is exactly what I try to do. The goal is to get the same perceptual effect whatever the note played. I do use the audio library for this project. A keyboard sends MIDI note numbers. Note frequency is compute according to octave selection, tune, pitch modulation. Oscillators are updated...
  21. E

    filter cut off frequency and keyboard tracking

    Hello, I want to implement keyboard tracking for the cut off frequency of a LP filter. I just can't find the maths behind... Say I play a A4 = 440 Hz. My filter is set on FC = 1000 Hz. A certain amount of harmonics are cut, which is what I want. But if I play A6 = 1760 hz, the fundamental is...
  22. E

    frequencyModulation & phaseModulation at the sametime ?

    Hello, I try to add a third input to the AudioSynthWaveformsModulated object, just the same way you did. I tried your code, but I can't make it work. I miss something... Could you give me to full synth_waveform.h and synth_waveform.ccp files ? It would be very kind. Emmanuel
  23. E

    AudioSynthWaveformModulated : add 3rd modulation input ?

    Hello, I would like to add a 3rd modulation input to the AudioSynthWaveformModulated object : - 1st input : Frequency modulation - 2nd input : Phase modulation - 3rd input : shape modulation I tried to edit the synth_waveform.h and synth_waveform.ccp files in the audio library, with no...
  24. E

    simple object recognition, any idea ?

    Thank you Michael, I have done projects with multiplexers, with hundreds analog inputs. I can confirm that is a very consistent approach, easy to code, robust and cheap. Your idea to code the coin value is interesting. I can imagine some kind of slots so each coin fit in its right position...
  25. E

    simple object recognition, any idea ?

    Hello, For a musical project, I need to find a way to identify simple wooden coins lying on a board. Say we have : - a board divided in a 64 cells, exactly like a chess board. - on a few cells, I put some wooden coins. They all have the same shape (say a small cylinder) but have different...
  26. E

    PTC thermistor for USB inrush current protection

    Hello, I work on a project that requires decoupling capacitors. One of them is large (220uF). It is used for decoupling an 0.96" oled display. These compact displays have a builtin charge pump circuit that introduces a lot of noise without large decoupling capacitors. I am looking for a way to...
  27. E

    non blocking I2C library ? or I2C OLED display alternative ?

    Thank you for your answer. I have found that the oled charge pump circuit is responsible for the noise. I think I am going to use other displays. Do you know some "quiet" alternatives ? LCD ? Emmanuel
  28. E

    non blocking I2C library ? or I2C OLED display alternative ?

    Hello, For various audio projects, I sometimes use small and cheap 0,96" I2C OLED displays. But they are a pain to integrate in audio projects. Here are my problems : - the I2C communication protocol blocks the program when the display is refreshed. It is a known issue. It is OK with slow...
  29. E

    audio DAC PCM1502 output level

    Thank you for your answers. I was surprised, but 2.1V RMS is indeed 6V peak to peak. Emmanuel
  30. E

    audio DAC PCM1502 output level

    Hello, I use a a pcm1502 audio doc. It works very well but the line output level is very high. With a full scale sine at 1 kHz, I get a 6V peak to peak output level. Is it normal ? My setup : Teensy 4.0 VCC = Vin 3.3v = N.C. GND = GND FLT = GND DMP = GND SCL = GND BCK = BCLK1 (21) DIN =...
  31. E

    noise, ground plane, amp PAM8304, best practices ?

    Hi, I have been using pam8304 class D amp for many of my projects. This amp delivers a lot of power from 5V. But it is a pain to reject noise. Digital noise tends to leak in power rails (I think). I would like to know what are the best practices to limit digital "leaks". I need advices for ...
  32. E

    i2s2 brings noise into analog inputs T4.0

    Hello, I can't get rid of noisy analog input when using i2s2 bus (same problem with i2s1 bus) Here is my test : I have a single pot hooked on Gnd - 3V3 - A9 I have attached a UDA1334A I2S Stereo DAC. It's working. When i2s is on, my pot values are very noisy (+- 30). When i2s is off (I just...
  33. E

    oscillator with phase modulation + frequency modulation

    Hello, I have already post similar question but the previous thread is old, so I start a new one. I have made a synth with a T4.0. This synth uses Frequency Modulation to generate interesting and complex waveforms. To get the best results, I use Phase Modulation. Within the audio design tool...
  34. E

    FM synthesis, unpredictable ?

    Hello, I have been using your code and it is working. I tried to use it with band limited waveforms, but unfortunately it doesn't work with it. I have been digging the code, but I am stuck. Would you have any idea ? Emmanuel
  35. E

    used Teensy for workshops ?

    Hello, I am looking for used Teensy for children workshop. I am building small synths with teenagers (https://youtu.be/RrDzcaljXUk). I am doing this as volunteer for a non-profit. I am looking for T3.2, T3.5, T3.6. I am in France. I can pay with Paypal or whatever is convenient for you. Thank...
  36. E

    max98357 + headphones output + line out

    It works. I have used a UDA 1334 DAC. This is perfect for line output. It is also known to be OK for driving headphones (even if it is not designed for it).
  37. E

    max98357 + headphones output + line out

    Thank you. I think the PCM5102 will be automatically set to slave mode if I connect the System Clock pin (SCL) to ground. I will try that and report.
  38. E

    max98357 + headphones output + line out

    Thank you Paul. I think I am going to add an i2s DAC (PCM5102) to get a proper line output. Do you think I can share the same i2s wires for both the i2s amp and i2s DAC (BCLK, LRCLK, DIN) ? Emmanuel
  39. E

    [queued] MiniTouch : low cost T3.2 synth for children workshops

    Hi, I have updated my synth a little. Minor bugs correction, stability and box design. I have also added a drum kit. I have re-draw the MIDI interface to tweak and save the presets. A lot of MiniTouch have been made now during various workshops. Children love it and some people use it on stage...
  40. E

    max98357 + headphones output + line out

    Hello, I have made a small synth powered with a little i2s classD amp : max98357. This amp is driving a small speaker. I am afraid this is not possible with this type of amp, but is there any way to add headphones output + line output from the max98357 ? I know this canot be done simply by...
  41. E

    LFOs different approach

    Thank you Mark. Frequency modulation sounds OK up to 20hz. Enough for LFO. Amplitude doesn't sound OK, as you mentioned. What do you mean by throughput ? I use a T4.0.
  42. E

    LFOs different approach

    Hello, I have build a quite big polyphonic synth with many oscillators, and 3 LFOs. The patch is quite complicated with many cords. To simplify the patch and the code, I tried a new approach for the LFOs section. My idea is to read the amplitude of my LFOs as fast as possible (2.9ms) with the...
  43. E

    I2S DAC with ampli + line out + headphone ?

    Hello, For various audio projects, I am looking for a "all-in-one DAC" (mono or stereo) : - line level output - headphone output - class D small amp Any idea ? For now, I use PCM5102 DAC + small class D amp. It works well. Emmanuel
  44. E

    how to declare multiple similar objects ?

    Working ! Thank you. Pt8211 was causing error when compiling, so I have deleted it and it compiles and plays. I am now going to understand better how this tool work. Emmanuel
  45. E

    how to declare multiple similar objects ?

    Thank you !! I am not a wizard of C++ as you can see... I have seen your enhanced audio design tool. I didn't try it yet, but it seems just amazing. I hope it will be the standard tool soon. Respect !
  46. E

    how to declare multiple similar objects ?

    Hello, This is probably a stupid question, but I don't know how to declare multiple objects. There must be a way to do this, but I don't know how. For instance, I have a MIDI controller with 24 pots. I use the ResponsiveAnalogRead library to smooth the noise. Then I make an array to handle my...
  47. E

    how to track filter frequency with midi note (keyboard tracking) ?

    controller #15 is mapped to filter FC.
  48. E

    how to track filter frequency with midi note (keyboard tracking) ?

    Here is a simple test code to demonstrate the problem. My issue is getting an even filtering "impact" from low to high pitch notes. MY guess : - less filtering for lower pitch notes. - more filtering for high pitch range. Emmanuel #include <Audio.h> #include <Wire.h> #include <SPI.h>...
  49. E

    how to track filter frequency with midi note (keyboard tracking) ?

    Hello, I try to find the correct formula to map the frequency of a filter with the note played on a keyboard. I first thought that was easy... but I am not happy with what I have tried so far. My approach is very simple : Freq(filter) = Freq(note) * k But it doesn't work. For instance when I...
  50. E

    FM synthesis, unpredictable ?

    Hey, it's working now !! Big thank you. Your code is really helpful. I hope this will be implemented on a new release. Emmanuel
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