Am I insane? (Arachnid)

PJS

Active member
So, I have an Arachnid board here waiting to be made. I am thinking about doing up a tap tempo arrangement for it. What I really want to do is that as it is a mono board, it is possible to use the second audio input as a tap input without worrying about the three pot inputs (or I suppose it could be a fourth pot input as well). The Arachnid board has the 2 inputs tied together (which makes sense if you are not using one). That will be easy to remedy with a Dremel. The thing is though that as the second input doesn't connect anywhere else, the only way to connect a tap switch to it will be to solder a lead directly to the IC pin - without shorting to any others. Am I insane to even think about trying it? Has anyone else tried a similar thing? How did it go? What are the tricks to help?
 
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PJS

Active member
Had a suggestion on a different forum to bend the pin up and then solder directly to it with it not connected to the board at all. That should work I think.
 
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phi1

Well-known member
The fv-1 inputs are high pass filtered, so it will be a bit odd reading the switch input (it won’t stay steady at 1.0 in code for example. You may be able to pick up the pulses in the code still. It my build I tied it into pot2, and used a resistor network to make it so the pot positions read 0.25-0.75 on the pin, and the switch pressed read 1.0. That way I could differentiate and still use all three pins for pots. I haven’t tried using the audio input so I can’t comment on which works better. I did find it helpful to use a ‘fast pot’ code snippet I found on the spin semi forum, to counteract the lpf on the pot pin, so it picked up my press more accurately. As you can imagine all this takes a fair number of lines to setup this way, so if using the audio input works well, let us know.
 

giovanni

Well-known member
Some of this could be address in the analog realm: adding an op amp integrator between the input pin and the switch may work. You’d have to work the math to figure out R and C.
 
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