☛ i-have-a-question @ spacecat.filou.se
☛ github
Made using HOTGLUE
simple MIDI synth module

microcontrollers oftentimes have integrated PWMs - so why not just
turn these into pwm based synths?

Seemingly [1] NES sound was generated using:
2 PWMs
1 triangle wave
1 noise channel
1 sample channel

[1] https://www.youtube.com/watch?v=la3coK5pq5w

so, really simple, 'init?

(other platforms used fm based synthesis, but that seems a bit more
complicated to do out of the box)

trying to rely on stm32s, because I'm familiar with them and they're

- PWMs: pretty much comme out of the box
- triangle waves: the stm32 DAC peripheral in theory has a triangle
wave and noise output (the noise is not satisfactory though)
- noise alternative: just randomly toggle a gpio pin (using the RNG
(or some floating gpio input) as source) :)
- samples: well there's a DAC


rotary woofer

Now that's interesting.

[1] http://www.rotarywoofer.com/
[2] https://hackaday.com/2016/03/30/rotary-subwoofer-combines-a-speaker-coil-w-a-fan/
[3] https://soundbridge.io/rotary-woofers/


- motor and control: check
- using polyurethane round belts from motor to blade axis (motor doesn't have to be on same axis as rotor)
- rc model helicopter main rotor head (Align 500 4 blade)
- needs some modifications to allow bigger angles

moving the rotor blades:

- model servo: mechanically too slow (for cheap model), furthermore in theory only 50 positional updates possible per second due to servo controls -> fail (digital control would be bothersome aswell)
- (small) dc motor: seems too slow
- commercial voice coil motor: way too expensive
- transducer (broken.. visaton bs 120): mechanically fitting seems promising, but seemingly not enough movement (heavy magnet is moving part in center)
- diy voice coil... (motor): possible, but elaborate
- old loud speaker voice coil: tests coming up (it's really what's been used otherwise aswell, so this should do the trick)

Anrechenbarkeit von Mehrstunden/Überstunden Teilzeitangestellter zum Versicherten Verdienst (AVIG)