Introduction: Hand-Washing Teaching Tool

I made this project for a university course. The purpose of the product is to reinforce good hand-washing habits in kids. Each time the sink turns on, the circuit playground is activated, and then if soap is dispensed, the circuit playground records a point. If the kid earns 10 points, the idea is that the parent would then reinforce the good behavior and give the kid a prize.


Scissors, computer, circuit playground, 2x micro USB cable, battery pack, 3 triple-A batteries, electrical tape, double sided tape, small cardboard box, common soap dispenser, conductive tape, paper towels.

Purchase a circuit playground:

Purchase a battery pack:

Purchase 2x micro USB cable:

Purchase conductive tape:

Step 1:

To begin, take your soap dispenser and remove the cap. (It is helpful to do this on a surface that you don’t mind getting a bit of soap on). Wipe the extra soap off of the tube with a paper towel and set aside.

Step 2:

Take your cardboard box and trace the opening of the soap container on the center of the side which you desire to have the soap dispenser protrude from.

Step 3:

Cut out a hole along the line you just traced. It is important to make sure the hole is just large enough for the soap container to come through, but not large enough for the cap to slip through once you twist it back on.

Step 4:

Stick the end of the bottle that you traced through the hole and twist the cap back on. If the hole is the right size, the soap should now be secured in place. Now, cut off any additional cardboard that prevents the base of the soap bottle from resting on the ground. If you don’t do this, the box may fold or crumple when you press down to dispense the soap.

Step 5:

Next, wrap the box in electrical tape to prevent it from getting ruined by water splashing on it, and to aid in the conductivity of the copper tape. Make sure the entire box is wrapped.

Step 6:

Before attaching your circuit playground to the box, go to and create this code and then download it to the circuit playground. You can customize the light colors and sounds if you want! After downloading the code, use the double-sided tape to attach the circuit playground to the center of the box on the side which you desire to be the front. Make sure pin A4 is on the top half of the circuit playground when you tape it on.

p.s. if you're new to makecode, this youtube channel has lots of helpful tutorials:

Step 7:

Insert the batteries to the battery pack and plug it in to the circuit playground. Turn it on, and make sure that the code works by clapping to trigger the red lights, and then touch pin A4 to trigger the green lights and record a point.

Step 8:

Once you’ve checked that the code works, tape the chord which connects to the battery pack to one side of the box and then stick the battery pack underneath the box and tape it to the inside. Make sure the on/off switch in facing outwards so that you can access it.

Step 9:

Next, get a piece of electrical tape that is long enough to reach from the nozzle of the soap dispenser to the backside of the box. Fold it in half so that the sticky sides are touching. Try your best to make sure there are no wrinkles.

Step 10:

Once you’ve folded this piece together, use two more pieces of electrical tape to fasten one end to the back of the box and the other end to the soap nozzle. This piece will act as a bridge for the conductive tape as it travels from the nozzle of the soap dispenser to the circuit playground.

Step 11:

Now, attach a short piece of conductive tape to pin A4. Use conductive tape to copy the circuit diagram below (the bright copper colored tape). Take your product to your bathroom sink and test it! If it doesn’t pick up the sound of the sink, you can adjust the loud sound threshold on with the loud sound threshold block.