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Project Help and Ideas » rewiring threadmill dashboard

March 16, 2016
by escartiz
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Hi everyone

I am trying to repurpose the motherboard and motor of an old threadmill to build a lathe. I will use the nerdkit for the readouts like shown on the digital calipers tutorial. I am not sure if I am posting in the right place as my question is not about the nerdkits part, It is actually in regards the possibility of swapping the huge dashboard for simple momentary buttons. I will only use the "start, stop, slower, faster" so no need for all the huge display taking up so much space.

The dashboard buttons consist of a two layer wired secction, not sure how to call this, its either ressistive touch or press to touch agains each layer. Any ways, out of all the traces between this 2 layers there is a 10 pin flex ribon cable that connects to the main board as you can see in the picture. Looking at the back of the dashboard I was able to trace the wiring as follows

Start connects to pin 1, 5, 2 Stop connects to pin 1, 9, 4 Slow connects to pin 1, 7, 4 Fast connects to pin 1, 8, 4

pin 1 and 10 connect each other, checking with a multimeter on the motherboard, both this pins have a 99 ohms resistance to ground.

Now, how would I go about wiring simple momentary buttons that only have 2 terminals instead of the original touch buttons that need a 3 wire connection? I notice that all of them share pin 1, is this like a common ground?

please advice, thanks in advance

alt image text

March 16, 2016
by escartiz
escartiz's Avatar

alt image text

March 17, 2016
by Rick_S
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More than likely, the ribbon cable is wired in a matrix of sorts and the "3rd" wire is just passing through for another button. I would guess, without being able to trace it out myself, that you would be correct to say that the pin 1 is a common, but again, that would be just a guess.

My next step and might have been my first would be to look at the circuit that the ribbon plugs into. Often this will connect to some sort of multiplex chip that will decode the keyboard input or some other method of logic. Tracing the circuit on that end may yield better results.

Let us know what you find.

Rick

P.S. - If these forums go away, an alternate site welcome to all has been setup HERE It is hosted by me. Right now there is about as much or less activity than here, but at least I'm available there unlike Mike & Humberto here. Several of the group have created accounts there.

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