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Old 29 July 2012, 16:15   #7
BulletMagnet83
 
Posts: n/a
Ahh actually, WinUAE is a very good idea, I'll definitely look into it. I've not personally used it but I have a passing familiarity with the concept... and if I can sort out some way to dump the contents I have a set of 3.0 ROMs from an A1200 I bought a while back which sadly was "significantly not as described". I guess mint condition/never modified means different things to different people...

The velocity sensing hardware should work by using an op-amp circuit with the trigger pad as the input signal source, set to provide an output between 0 and 5V. This output is then fed into one of the A/D channels on a suitable microcontroller. There could be perhaps 6 or 8 channels depending on the MCU used. Each of these channels is repeatedly polled, and on each channel's "turn" several samples are taken for the duration of the trigger pulse length, with the highest value being used.

Once each polling cycle is complete, the MCU should have collected a complete set of data for what was happening to each pad during that window of time. This can then be sent out over a serial port.

The trick will be doing this fast enough for a semi-realistic playing response. The hardware SHOULD work, but until I actually have the free time to build it and test some code I have NO idea how well it will react to being played. But code can always be tweaked and modified once the basic hardware's layed down A suitable test would be to rig the pad-sensing gubbins up to a PC/serial monitor and see if what I hit bears any resemblance to what appears on screen! If it doesn't work at all, I have some other options to explore.

Based on what I've managed to get my head around so far, I think it's going to be the hardest part of the project.


EDIT FOR UPDATE:

I've actually just found a project very similar to what I intend to undertake, so (woo yay!) a lot of the electronic design process has been done for me. http://www.edrum.info/schematics.html. Of course, I'm tooled up for a different family of microcontroller and I want to do the UI a bit differently so I can't copy it ALL, but hey... it can be done/has been done before. So there's hope for this endeavour yet

Last edited by BulletMagnet83; 29 July 2012 at 18:51.
 
 
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