Introduction: Laundry Warning Sign

I created this project for a multimedia digital making class. I created this project as a way to warn people to check their pockets for valuable items before they wash their clothing. This project does not require very much prior experience, but there is some soldering involved. Have fun following along with this instructable to create the Laundry Warning Sign!



Soldering Iron

Wire Stripper

Exacto Knife

Pocket Knife


Circuit Playground

Battery Pack


LED NeoPixel Lights

Photo Album Storage Box

HDMI Cable


Parchment Paper

Command Strips

Step 1: Soldering and Constructing the Circuit

The best place to begin is by soldering and constructing the circuit.

First, you want to make sure you have wires cut to the right size. I chose to cut them so that each light could be about one inch apart. Then you strip the wires so they can be soldered.

I chose to use five NeoPixel lights in my sign, but this can be adapted to as many NeoPixels as you want.

Each NeoPixel has four thru-holes. One is positive, One is negative, one is the signal input hole, and one is the signal output hole. The input hole is marked by the arrow pointing towards the center of the circuit, and the output hole is marked by the arrow pointing away from the center of the circuit. For the input and output holes, each hole only has one wire soldered into it. Make sure the wire connects the output hole from one NeoPixel to the input hole of the next NeoPixel. However, for the positive and negative connections, it will be different. Both the positive and negative connections only have one hole on each NeoPixel. Because of this, you must solder together two wires into those holes. The two wires will be soldered together into the hole at one end, and then one wire will connect to the respective hole on the NeoPixel ahead while the other wire will connect to the hole on the NeoPixel behind it. At the end of the strand, the last NeoPixel will be soldered to the Circuit Playground instead of another NeoPixel.

Solder the five lights and their connecting wires into a straight line. Make sure you solder the NeoPixels in a way so that the arrows marking the signal holes will be pointing away from the Circuit Playground.

Next, you will want to connect the Circuit Playground to the rest of the lights.

I cut the wires that connect the last NeoPixel and the Circuit Playground to be about 27 inches. This length will depend on the arrangement of your washer, but you will want it to be long enough that the sign can hang on the wall above your washer while the Circuit Playground is resting flat on the washer lid.

Solder the wires from the last NeoPixel to the Circuit Playground. You will want to make sure that positive connection is soldered to the hole that is labeled "V OUT", the signal connection is soldered to the hole that is labeled "A1", and the negative connection is soldered to the hole labeled "GND."

After these NeoPixels and the Circuit Playground are all soldered together, then your circuit should be complete.

Step 2: Programming the Circuit Playground

The simplest way to program the Circuit Playground is through Microsoft Makecode. Microsoft Makecode is easy because you just drag and drop blocks of code.

Because I wanted my warning sign to be annoying, I programmed my Circuit Playground to flash bright lights and make an annoying sound, but you can program it to react differently.

First, you go to the Microsoft Makecode website. This can be found here:

It can also be found just by Googling 'Microsoft Makecode.'

Once there, click on Circuit Playground Express, and then on New Project.

Plug your Circuit Playground into your computer using your HDMI cord. Before attempting to load any code onto the Circuit Playground, press the small reset button on the center of the board until you see the lights flash green.

To recreate the code, you can just follow the picture of code included above. Otherwise, my code will be written out here below.

Once you actually begin coding, make sure you have both a green 'forever' block and a green 'on start' block.

On Start

The 'on start' block will only have one main block inside.

It will say:

{set [strip] to (create strip on [A1] with (5) pixels)}


The 'forever' block contains a few more complicated parts.

The code is as follows:

{if <(absolute of (acceleration (mg) [x]) [+] (acceleration (mg) [y])) [<] (120)> then


{[strip] clear}}


{show ring

A picture of the Circuit Playground will appear here in the code. The picture allows you to choose which colors you want the lights on the Circuit Playground to be.

{play sound [ba ding]}

{for (index) from 0 to ([strip] length)


{set [strip] pixel color at [index] to (here you can choose the color that you want for the NeoPixel lights)}

{set [strip] brightness (here you enter in a value that controls the brightness of the NeoPixel lights)}

Once you have put this code together, press the Download button and load the code onto the Circuit Playground. It should now flash and make sound when tilted.


I relied on this code ( found here ( in order to make this code. I took portions of their strand test code, so that I would know how to correctly program the NeoPixels, and I combined it with the "If, then" statement code used for the accelerometer.

Step 3: Creating the Sign

First, you will want to cut out the word/words into the lid of the box. Trace the word on the inside, and then cut out the letters with an Exacto knife.

Next, Slice off the top half of the bottom of the box using a pocket knife or other sharp tool. Cut out a small piece on one of the corners of the box, so that you can thread the wires through that corner.

Then cut a piece of parchment paper to fit perfectly into the lid of the box, and tape it in.

Tape the NeoPixels circuit into the bottom of the box, and then put the lid on top. Tape that into place.

The sign is now complete!

Use a Command strip to stick the Pockets sign onto the wall. Place the Circuit Playground on the washer lid in the desired place, and tape it on.

Turn the battery pack on, and now your warning sign is functional!

Step 4: Tips, Tricks, and Thoughts

  • When creating the circuit, it is best to have three different colored wires: one color for negative, one color for positive, and one for the signal connection. This can help you tell the wires apart when you're working with them.
  • After you have soldered the long wires to the last NeoPixel, but before you've soldered the other end of the wires to the Circuit Playground, braid the wires together. This will keep the wires from tangling, and it also eliminates problems caused by EMI(electromagnetic interference). If you don't have three different colored wires, mark the ends of the wires with three different colored markers so that you can tell the wires apart after you've braided them.
  • When creating the sign, make sure you slice the bottom of the box as evenly and straightly as possible. If it is crooked, then the lid won't fit on it very well.
  • In all instances, tape can be substituted for glue for a more permanent solution.

While my sign is supposed to warn someone to check their pockets before washing their pants, this technology can definitely be applied in different situations. Maybe you need a warning sign to keep your little kids from touching fragile items, or maybe you need a warning sign to keep your roommates from taking your food in the pantry. Be creative and figure out what others ways this idea can be utilized!