Two ESP32's One Switch

Projects General Guidance
1

Hi everyone,

I’m just about to start my first project and I’m seeking help with a hardware issue.

What I plan to do is operate two mobile phones to take stereo photographs/videos by programming two ESP32 dev boards to act as Bluetooth triggers for each phone. Both dev boards will be running the same program and will be triggered to send the appropriate keyboard code to the phone with a simple push button. In order to get good stereo results both phones should take the picture or start video recording at the exact same time so using the same button for both dev boards should help in that respect. To start with I will only be using one switch to send VOLUME_UP to the phones but if things work out then the next stage will involve several switches (up to seven) to be able to simultaneously do things like zoom both phones or adjust exposure.

Initially I thought I would configure the same GPIO pin on each board to be an input with internal pull-up resistor with a SPST-NO momentary switch connected between the two GPIO pins and ground – this would connect two GPIO pins on two dev boards together so their internal pull-up resistors would be in parallel which probably isn’t a good idea. My second thought was to do the same thing but using a suitable external pull-up resistor instead. My third thought is to use a DPST-NO switch with internal pull-up resistors which would isolate the two dev boards, however sourcing suitable switches is proving to be a problem.

I would welcome any advice or comments, particularly on my second thought … is that a viable option?

Thank you.

2

Welcome to the forum

Maybe use a single SPST switch and a diode to each of the 2 GPIO pins to isolate them from one another ?

3

Thanks UKHeliBoby for the quick reply, yes that would work although when/if I go to the 7 switch solution that would be a lot of diodes.

4

I see nothing wrong with that as long as the grounds on the 2 boards are connected together.

5

Thanks PerryBebbington that's interesting, as it happens I do intend to power this remote with batteries via a suitable 3.3v regulator so both ESP32's will have a common ground and +ve.