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Help with making a triangle wave sequencer with pitch relative to tempo, please? Answered

I'd like to make a low frequency triangle wave oscillator/sequencer, but the oscillator and sequencer have to somehow be synchronized with each other, so that if the tempo gets doubled, for example, the pitch also goes up one octave. How can I do this? I've already made a circuit based on this oscillator and the 4017 decade counter as a sequencer. (Ignore all capacitor, resistor and pot values; I haven't defined them yet)

Question by aelias36    |  last reply


turn a square wave froma 555 into a sine wave? Answered

I would like to know how to smooth out a square wave to turn it either into a sine wave or at least a triangle wave. Or if it's not possible i would like to know how to make a sine wave generator to use as a lfo thing for a home made synth. Thanks, Josh1324 PS. It has to be analog, im not getting into microcontrollers or anything digital.

Question by josh1324    |  last reply


Audio reactive stepper motor control

Hello, i'm new to the instructables-comunity and i just started to work with arduino some months ago. I've already made some small projects with a stepper motor and a project with a SD-Card-mp3 player for arduino. For my next project i would like to work with audio reactive stepper motor control. To do that, i already bought the SPARKFUN SPECTRUM SHIELD , an Arduino Uno and a hand full of the wellknown 28BYJ-48 Stepper Motors (5V) and the matching ULN2003APG shields. In the description of the SPARKFUN SPECTRUM Shield it is mentioned that it can also be used to control motors (audio reactive). Unfortunately I couldn't find a code or a manual for it yet. The SPARKFUN SPECTRUM Shield divides an audio signal into 7 frequency ranges (bands). I would like to drive 7 stepper motors in combination with the Shield. Each of these motors should move in one direction with constant speed as soon as the respective frequency range reaches a certain sound level.Does anyone know the SPECTRUM SHIELD and can help me? Or has someone already carried out a similar project and can give me some advices? Maybe an Arduino UNO is not enough powered... and I should rather use a bigger microcontroller? I am grateful for any advice. I'm looking for hints on the coding and the wiring.I attached a rough scheme of my planned project.And here is a PDF for the MSGEQ7, of them two are used for the SPECTRUM SHIELD.Would love to get some help from the community!

Question by _Alex_Rex_    |  last reply


Arduino Uno Synth project - Audio output questions

Hi! I am developing a synth/sampler project based on the Arduino Uno r3. This is my first electronics project ever and because of that reason I have some questions which I can't find a definite answer for on internet. The synth has two function. It has a tone generator using the ToneAC library. With code I have mimicked LFO and VCO functions, using potmeters I can adjust the frequency and LFO speed realtime. The other function is that I can trigger samples stored on a SD card using the TMRpcm library. The device will be used in nightclubs on high end soundsystems and PA. I am afraid I will damage the equipment with my device because I do not send a pure audio (AC?) signal. Currently the flow is like this: PWM output (pin 9, 10) -> voltage divider to 2.5v -> RC Low Pass Filter 15Khz -> LM386 amp with volume control -> mono jack output -> mixing desk -> amplifier -> speakers (the TMRpcm and ToneAC library share the same pin (9), I have fixed this by disabling the TMRpcm when the ToneAC is playing and vice versa. The mono jack is wired as follow. pin 9 goes to plus side of mono jack output, pin 10 to negative side. The TMRpcm pin 9 also needs to go to plus side of mono jack output, and mono jack negative needs to go to ground. Because I disable the ToneAC at that time I consider port 10 grounded because it not generating any sound so there is no signal/voltage running out of it, aka the IO pin is set to LOW) I am hoping that using the voltage divider I am within range of the Audio Line levels of a default mixers Line-IN (like Pioneer, Behringer, etc). The RC Low Pass Filter is used to filter of inaudible frequencies and clean up the sound a bit, the LM386 audio amp is used to amplify the signal and (hopefully) make it a real audio signal. The lowest frequency you can play with the synth is 100hz and the highest frequency is 3100hz. Because I lack a lot of knowledge in this field and because I do not own a oscilloscoop I can't say for sure if my output signal is harmful for the equipment and was hoping to get some guidance on my project on this forum.

Topic by erik404