Now that you have the example working, you can make a funny prank device. This code will wait a random amount of time, and then randomly hit a key.
TrinketKeyboard prank example
For Trinket by Adafruit Industries

#include <TrinketKeyboard.h>

void setup()
  // start USB stuff
  while (TrinketKeyboard.isConnected() == 0); // wait until connection
  randomSeed(millis()); // seed the RNG
  // the HOST takes some time before isConnected can return true
  // this amount of time is hard to predict, it depends on how busy the OS is
  // we use this unknown time as the seed

void loop()
  unsigned long secs_to_wait = random(60, 120); // generate a random amount of time
  unsigned long time_stamp = millis();
  while (millis() < (time_stamp + (secs_to_wait * 1000))) // wait the random amount of time
    // the poll function must be called at least once every 10 ms
    // or cause a keystroke
    // if it is not, then the computer may think that the device
    // has stopped working, and give errors
  TrinketKeyboard.typeChar((char)random(33, 122)); // type out a random character (valid ASCII)
Plug this into your friend's computer and hide it. For extra credit you can modify the code to randomly press the CAPS LOCK key, which will really confuse your victim!

This guide was first published on Sep 27, 2013. It was last updated on Mar 08, 2024.

This page (Prank Example) was last updated on Sep 27, 2013.

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