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Forum Index : Microcontroller and PC projects : Picomite Project Suggestion
| Author | Message | ||||
| Volhout Guru  Joined: 05/03/2018 Location: NetherlandsPosts: 5091 |
This is just an idea that popped up again into my mind this morning while listening to music. It has been on my mind since I saw the stepper motor video on Youtube, I want to share with you: steppers playing music With picomite we can do this. I think I figured out what is behind this. If you look carefully, the motors always run clockwise. This means that the stepper motor has no intelligent control, but simply has the direction fixed. The only thing you need is a square wave at the STEP input with the correct frequency. Picomite could do this using 4 PWM's set to 50% dutycycle, with varying frequency. (MX170 only has 2 PWM frequency's, so it could not do it). OK, where to get the music.... I think they use midi files. In midi files, notes and duration and channel are nicely packed. So you need a 4 instrument midi file, or you need to create one from a 4 voice (SATB) choir score. There are several PC programs that can do that for you. So a midi file must be parsed. You only need to parse the leader (speed), but could even hardcode that. I think the program should use a heartbeat of 1/8 (faster notes won't play nicely anyway on steppers). Then parse the midi channel/tone/duration. Channel shows what PWM to program Tone can be used (via a lookup table) to set PWM frequency. Duration must be translated in heartbeat ticks. You can test the parser by simply taking the 4 PWM outputs via identical (10k?) resistors to an audio amplifier. Transitions will sound horrible, and everything is square wave, so very sharp, but the music should be recognizable.. The stepper drivers must be set to FULL stepping (not half stepping or micro stepping) because you need them to make noise, not behave good. The guitar is there to amplify (they probably even use the instruments pickup to connect to an amplifier/recorder). I thought I pick this up myself, but have few other projects that have been prioritized by my wife. So if someone else feels this is a nice challenge, please prove that the picomite can do this.... Volhout P.s. you may need to octave the voice when it exceeds 1kHz, since steppers will not run at these very high frequency's) Edited 2021-06-18 19:27 by Volhout PicomiteVGA PETSCII ROBOTS |
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hitsware2 Guru Joined: 03/08/2019 Location: United StatesPosts: 719 |
It sounds like PWM music ( signals ) through an audio amplifier and speaker . I would surmise the steppers are only there for the visual effect . The newer controllers with multiple PWM frequencies are quite music capable . my site |
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