Make a watch timer with your Adafruit Circuit Playground Express

Duration: ~15 minutes


  • Tape (masking, duct tape, and/or packing tape)
  • Scissors
  • 1 Adafruit Circuit Playground Express, battery holder and 2-3 AAA batteries
  • 1 small patch of velcro tape
  • (Optional) a picture frame, to help you tape the wristband together

Preparing the battery holder

Add batteries to the battery holder before you start. If you want, wrap the battery holder in construction paper or in some fancy tape to make it look nicer. Oh yea, make sure the on / off switch isn’t covered up though!

Making the wristband

Put tape across one side of the picture frame.

Flip the picture frame over so can you see the sticky side of the tape you just put on.

Add another piece of tape over the first piece. Try your best to make the second piece of tape totally cover the first one.

Cut the double piece of tape free from the picture frame.

Next, put the velcro tape on both ends of the wristband. Start by putting a patch of velcro at one end of the wristband.

Flip the wristband and put the other velcro patch at the other end. It is important to flip the wristband so that both patches of velcro meet when you fold the band on itself.

Mounting the battery holder

Next, we’ll need to attach the battery holder to the bottom of the wristband. Place your wristband flat on the table, and put the battery holder on top of it, near one end. Make sure the on / off switch is facing up, and that it extends away from the tape so it doesn’t get covered up.

Put tape over the battery holder to hold it in place. Try to line up the tape with the wristband so there is no sticky part left over to grab your skin. Ouch!

Mounting your Adafruit Circuit Playground Express

The last step is to attach the board to the top of the wristband. Put on your wristband, but make sure the battery holder is on the bottom of your arm, like you see in the picture above.

Now, take a small piece of tape and fold it onto itself so its sticky side is all around on the outside.

Place the piece of tape on the bottom side of your Adafruit Circuit Playground Express. Stick the board to the top of the wristband, on the opposite side of the battery holder.

Your watch timer is ready! You can reuse this as a wristwatch and code many new projects that use it. Ok, let’s go on and code the timer.