Adafruit Circuit Noise Level Detector

This project is designed for as a tool for classroom setting to help with noise levels during independent work. It detects the noise level in the room. If the noise reaches a certain level, a noise and lights will go off to notify the class to lower their voices. There are 3 LEDs on the side, on will light up each time the noise level is too high. The goal is to not let it go off 3 times.

• a small cardboard box
• adafruit circuit playground express
• 3 LED lights (like these)
• solder wire
• coated wire
• soldering iron
• wire stripper & cutter
• paint
• tape
• fabric
• hot glue/glue gun
• scissors

Start by mapping out how your circuit will work. You will need to connect the negative side of the wire to a ground pin and the positive side to one of the numbered pins. I used pins A4, A1, and A7.

Originally, I wanted my circuit to sit in a circle shape and be completely visible, but later I changed that and cut out a bigger section in the box to put felt fabric over.

For now cut out a rectangle where you want your circuit to sit, then paint the entire box for the look you want.

After the paint has dried, poke the prongs of the LED lights into the box. The longer prong is the positive and the shorter is negative, be sure to label which side is which so there won't be any confusion later.

Now you will need to program your circuit so it can sense the noise level. Here is what my code looked like. You may need to experiment with the noise level and adjust the noise threshold variable number on start.

Once your circuit is programmed you will need to cut six wire pieces to attatch to each pin we will use. Strip the ends of the wire so you can wrap them around the pin multiple times.

Now that the wire is in place, solder the wire to the metal part of the pin. Then twist the wire around the LED prongs making sure the ground pin is connected to the negative and the A pin is going to the positive.

Check that the circuit will line up in the correct spot. Cut a piece of felt that will cover the rectangle opening in the box and glue it the front side. Take a piece of tape and tape the circuit to the fabric from the inside.

Connect the battery pack to the circuit and turn it on. The lights should turn on, test out the noise sensor and see if all of the LEDs will turn on.