Capacitive Touch Interactive Board

This is a fun project for anyone who wants to make a touch interactive board! It uses capacitive touch of the Circuit Playground in order to activate lights surrounding the board. It has three different sensors: two capacitive touch involving the metallic bows seen at the top of the board, and a slider which involves a distance sensor that activates when the slider is completely to one side. Decorative stickers are placed throughout to enhance the sensory experience.

Material list:

1x Circuit Playground: https://www.adafruit.com/product/4333

1x VL53L4CX Time of Flight Sensor: https://www.adafruit.com/product/5425

1x Stemma Qt Cable: https://www.adafruit.com/product/4398

2x Alligator Clips: https://www.adafruit.com/product/1008

1x NeoPixel RGB Strip: https://www.adafruit.com/product/4245

2x Metallic material of your choice (I used metallic bows)

Wood sheet (1/4" or 1/8") - around 13"x30"

3-D printing material of your choice

Machines used:

Laser Cutter

3-D printer

Hot Glue Gun

- Laser cut two circles with radius of 6" which will serve as a base and top of the board

- On the top circle you will also cut 4 circles for both the capacitive touch objects to be located and the distance sensor to have a place for the wiring to come out of. I did 1/4" radius for the wires for capacitive touch and 1/2" radius for the Stemma-QT cable to come through

- Then we need to laser cut a stand for the bottom platform so the board is slanted and therefore more easier to touch the objects. I created a based (seen above) with a rectangle, a right triangle, and a scalene triangle in order to get a slanting effect. Based on high you want your slant, you can increase the hight of the base right triangle, and then adjust the length of the scalene triangle to match.

3D printing:

- We only need to 3D print out our slider seen above, the STL file is attached

- Just hot glue the two segments together to make a long enough rod for the slider to function.

Once we have our desired slider, we have to make platforms for it to rest in.

- Laser cut a platform shown above. The design is just a semi circle placed upon a rectangle placed upon a triangle and then join them all together. The circle at the top should match the dimension of the rod for the slider with a little wiggle room so you can still glue in together.

- The only difference in one of the supports is that it needs a rectangular hole big enough for the distance sensor to sense through as seen above (3/4" x 1").

All processes involving machinery is now over

- We then cut our desired length for the light strip, just wrap it around the board, mark where it stops and cut with some cutters

- We then can hot glue the strip to the board itself

To set up our circuit, we place the CPB in the middle the the Stemma ports attached, strip attached the power A1 pin and ground, and alligator clips attached to A3 and A6.

I used some electrical tape to hold the circuit in place for now.

The code itself is not difficult to understand using Circuit Python:

- We continuously scan for touch on ports A3 and A6 while also accounting for the slider being close enough to the distance sensor where it registers the desired value.

- Based on what occurs, different rgb lights are shown in a circular pattern. The capacitive touch sensors will take priority over the distance sensor if they are being touched for easy usage of the board itself.

A nice paint-job will go a long way for the board as well, so we do this before we go any further. We paint the top, bottom, and the slider with paint to make it pop more.

We then test our code before gluing any circuit down. If your code is working and is all good, we can proceed to hot glue all ports connected on the cpb for durability while also gluing down wires so they stay still while using.

The next step is to attach a battery pack to the cpb and I rested mine with the hollow cubby within the stand for the board.

You can then assemble your slider so it matches the diagram above. Two on each side with the one with the hole on the inside on either side.

You should then hot glue your distance sensor to the support for the slider with the hole and maker sure it registers your slider by testing the code out.

You can then finally hot glue the led strip and the bottom board together to get the desired board.

Then, attach your metallic objects to the alligator clips, and hot glue down your supports to the top of the board.

Flip your battery pack on and off and the light strip should light up white indicating everything is working.