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Author Topic: Simulating a key press  (Read 1378 times)

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Offline ganaps2Topic starter

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Simulating a key press
« on: May 28, 2017, 04:13:21 am »
I have a system that has membrane switches with contact pads on PCB connected to the microcontroller in a matrix fashion. Need to simulate the key press without the actual switches from an external microcontroller. Any idea of how to do this?
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Offline Paul Moir

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Re: Simulating a key press
« Reply #1 on: May 28, 2017, 04:19:12 am »
A bunch of opto-FETs too expensive?
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Online Ian.M

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Re: Simulating a key press
« Reply #2 on: May 28, 2017, 04:27:48 am »
That's the general approach, but if you have a common ground you can also use analog switches, and if its a regular matrix, an analog crosspoint switch can be a one-chip solution with a simple SPI interface.
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Offline KL27x

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Re: Simulating a key press
« Reply #3 on: May 28, 2017, 08:22:32 pm »
Done this with keyboard... Bog standard BJT output optocouplers work fine in this case. Zero voltage drop of opto FET not necessarily needed.
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