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I'm a total noob when it comes to the use of opto-couplers, but I'm trying to connect up a couple of digital pins between an ESP32 and a small voice module. There are two pins that I need to switch in order to do remote-updates on the second device from the ESP32.

  • One pin is a programming mode pin that has an internal pull down. It needs to be set 'high' prior to a reset to trigger a given device mode.

  • The second pin is a reset pin with an internal pull-up that needs to be pulled low (shunted to ground) momentarily to trigger a device reset.

I basically need to pull the one pin high, momentarily connect the reset pin to ground (pull it low) then I can release the other pin after the reset is triggered (probably with a slight delay - not sure how quickly this thing detects the mode pin).

I'm sure there's a way to do it, but not being familiar with how the opto-couplers work in a circuit and not being an EE, I'm not even sure where to begin.

Oh and I forgot to add, my ESP32 board has built-in level converters as does the module, thus I'm operating with 5V.

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  • \$\begingroup\$ are the optos open drain? if so, you have the active low done, then you just need to pullup the other one with a 10k to vcc; when the GPIO is high, the opto will be low. \$\endgroup\$ – dandavis Dec 19 '18 at 19:27
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    \$\begingroup\$ Why do you think that you need optocouplers? \$\endgroup\$ – CL. Dec 19 '18 at 20:20
  • \$\begingroup\$ I don't think I need them, I just want to learn more about them and how to use them. I have no idea if they are open drain. Like I said, total noob here! \$\endgroup\$ – Scott Wood Dec 20 '18 at 20:34

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