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Mitxela Stylophone Card meets Flash Synth, is this alternate application viable?
Tank Posted: 15 Apr 2022, 10:26 PM

Posts: 1
Joined: 15-April 22
Had this Mitxela-inspired thought ages ago, done nothing with it. Seeing a recent video prompted me to post it, it might inspire someone else.
The elephant in the stylophone business card room, if I may say, is that there's no stylus. Pondering this thought, it occurred to me that one wire people often carry is a usb cable hanging from a battery pack, a 'power bank' for charging your smartphone.

You could mount a stylophone resistor/pad array on the side of a battery pack, and use the usb cable's outer metal ground as the stylus.* **

It could just be a 555 timer synth, powered by the battery pack, no amp, circuit design around mod-ablity (and aesthetics!).
Perhaps a circuit printed resistor track for your finger for the feedback mod.


You could go full Mitxela, have a microcontroller, surface mounted LEDs above each key and a momentary switch. Perhaps some coloured labelling and an RBG LED on the faceplate, printed instructions on the back. Use these cheap surface mounted components, and the array of stylus/contact pad switches, to cram in an interface for a plethora of voice/banks of polyphonic multi timbre (drum) synths; a recording/step editing/live track muting sequencer; patch editing. An opportunity to guide people on their first steps into binary or hexadecimal. Synthesis, FM?

You could forgo a speaker and headphone amp (and a DAC?) by bluetoothing the audio straight to your phone. Even send and receive MIDI over the bluetooth standard.
Easily transmitting from a bank of switches over bluetooth could be interesting too.
Could plug it in for MIDI over USB and use the second USB port (and 2nd cable!) as the stylus.

My original hope was that this is a useful variation on a DIY 555 stylophone/APC - one you'll use more, because it's already in your pocket.

But, although these battery packs are expensive, this is only one board. An existing enclosure might not need much modification - redesign one side of the enclosure to hold the board, and expose the keys and resistive strip; drill a hole for the momentary and attach it; solder two wires for the power, perhaps one for the stylus?
That's it.

I understand, perhaps incorrectly, that much of the power handling is embedded in the battery, so it may be feasible to replace the existing board entirely, put the hardware all on one, and have a higher definition battery indicator, a user interface with a button and fewer jobs at assembly. There's likely a mass produced, off-the-shelf daughterboard in use on the existing hardware.

Is there a commercially viable product idea here?
If so, go nuts, give me a box of them and buy me a pint.
And dinner.
And phone me once in a while, yeah?

*given their ubiquity and low cost, if it's not possible to use the existing USB ports for the purpose, you still get the functionality by adding a front mounted 'dummy' USB port solely for the purpose of the stylophone.
**If wear is going to be an issue, but for extra cost of manufacture and assembly, include a rounded stylus with a micro/usb-C port at the other end, perhaps secreted like a gameboy stylus...or don't include one - eith way, both DIY and after market tastic!

Last edit by Tank at 15 Apr 2022, 10:30 PM

mit Posted: 16 Apr 2022, 10:15 AM
yeah whatever

Posts: 541
Joined: 4-May 16
Interesting idea, using a USB cable as a stylus. I have a feeling it would be a bit sharp and more likely to damage the keyboard.

Saying that, the keyboard on the existing stylocard is tougher than most people assume. In the video, the grey marks on it are from the crocodile clip abrading, and wiping it clean afterwards it looks fine. Makes sense, because underneath the gold plating it should be copper coloured, not grey.

The 2018 edition of the stylocard had a built-in stylus but I never made a video about it.


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