I am using an Arduino Uno and would like to simulate a capacitive tap with zero human contact on my iPhone 5 screen.

What seems to work right now is putting a coin on the screen and connecting the coin to a power source (such as Digital I/O Pin) and when voltage is sent to the coin it triggers a "tap" on the screen. Is this safe? Is there a better way to do this? I just read somewhere else that any grounded conductive object should work. Is it better to ground the coin or to connect it to a power source? Also, how can I stop sending current to/grounding the coin so the simulated touch is stopped. Right now, I can't get the arduino to stop "touching" the screen.


1 Answer 1


When I used to work in touchscreen development, we had a couple of methods to achieve exactly that. The first was to interrupt the connection to ground with a miniaturised relay. The shorter connection between the relay and the "finger" the better. The other method was to use an RC servo, which simulated a mechanical finger. Both worked, but obviously the relay was faster acting.

  • \$\begingroup\$ Can you provide a link to a miniaturized relay I could use? Would this work: amazon.com/WINGONEER-KY-019-Channel-Module-arduino/dp/… \$\endgroup\$
    – Caders117
    Feb 23, 2019 at 0:11
  • \$\begingroup\$ Or this: amazon.com/Tolako-Arduino-Indicator-Channel-Official/dp/… (I think they're the same thing, just this one has better reviews) \$\endgroup\$
    – Caders117
    Feb 23, 2019 at 0:20
  • \$\begingroup\$ pretty much any of the Omron G6K would work, but all you reall yneed is just a small relay. digikey.no/products/en/relays/signal-relays-up-to-2-amps/… \$\endgroup\$
    – Elmesito
    Feb 23, 2019 at 8:35
  • \$\begingroup\$ This might work in some cases, but it is not a general solution. At the least, if you are going to use a servo, use a touch stylus determined to work with the target screen. \$\endgroup\$ Feb 28, 2019 at 21:28
  • \$\begingroup\$ Test environments use a small surface area metallic probe with a small reed relay to do this. It's very common. I've seen both multiple fixed position probes and 2D positioning systems used (no Z involved). Typically the 2D positioning is used where you need to emulate screen swipes. \$\endgroup\$ Feb 28, 2019 at 22:23

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.