I'm having 7 raspberry Pi's 3 connected to 7 screens, running an python 2.7 app to download different images from google drive, every raspberry has different images. Geeqie is displaying those images in an slideshow. The idea is to have one hardware scrolling mechanism (like an rotary encoder), providing the same input at the same time to all 7 Raspberry Pi's their GPIO input pin (or pin's in case of the rotary encoder). The python script handles the input. This is required so all images switch at the same time in geeqie.

Any idea's how to provide the same input signal at the same time in all 7 Raspberry Pi's 3 their GPIO input pin('s)?

It's not really clear to me how this circuit would look like. With keep in mind the max input current.

My idea's so far: idea1


  • 2
    \$\begingroup\$ Just connect the signal to all 7 GPIO pins. I don't understand where your rotary encoder comes into this. By the way: forget about the maximum input current. Just keep your voltage between 0 and 3V3. \$\endgroup\$
    – Oldfart
    Dec 11, 2018 at 7:21
  • \$\begingroup\$ The rotary encoder is for the detection in python to go to the next image on all rasberri's at the same time. How will the circuit look like then? Like in the first image? I don't want to overload the GPIO pins. \$\endgroup\$ Dec 11, 2018 at 7:45
  • \$\begingroup\$ No , like in the second picture. \$\endgroup\$
    – Dorian
    Dec 11, 2018 at 9:09

1 Answer 1


Just connect the activation signal to all 7 GPIO pins.

You can only overload an output. (Where overloading means: taken more current then they can provide).

Inputs can not be overloaded in hat sense. You can 'overload' them if you put too much voltage on them. But if you keep between 0 and 3V3 the Raspberry-Pi will have no problems.

The signal going into them must be able to drive all inputs but as we have CMOS inputs and, I assume, the signal is very slow, 7 pins is not a big issue.


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