TranceVibe Take Two: So, what are they doing that I’m not doing?

After getting busy with all kinds of other stuff for…heh, a year…, I started thinking back on the Drmn’ TranceVibe project. My grandmaster plan was to “mass” (qty: 20 or so) produce them and see if they’d sell. Anyway, since the original design, a few small cost and manufacturability enhancements have been made: smaller SMD oscillator clocked down to 4MHz (cheaper, sucks less current, and most importantly doesn’t poke through the board where the PIC goes), programming jig (eliminates program connector with same pokeybit problem*), smaller (less flash memory) PIC (I’m still only using a fraction of it), so now the whole thing could theoretically be reflow soldered. The board is still original, since I got a batch of about 30 of them and haven’t really used any. They still need to be cut by hand.

Sort of by chance, I also stumbled on OpenDildonics, which has a photo of the original ASCII vibe’s innards. Holy overdesign Batman! I don’t know whether to laugh, cry, or buy one off Ebay so I can figure out just what the hell it’s doing. Unless it serves double duty as a trance vibrator and some bizarre harmonic mind-control device, there are far too many parts on this board.

Actually, it looks like they’re putting out the 1-byte “how much vibration” level, converting it to an analog value and driving the motor linearly. I can’t think of why they’d take this approach over a simple PWM controller (which is what the Drmn’ Trance Vibe does) except to avoid the recurring voltage kickback as the motor power is switched on and off, but this can easily be snubbed with a fast diode (indeed, most FETs, including the ones used on the DTV, have a built-in body diode). Maybe microcontroller technology hadn’t advanced to that point by then where they could just run a PWM loop and handle the USB port at the same time.

* note to self: beer and CAD do not mix.


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