Building Interactive LED Art Using 1000 Photoresistors

Background : We found on the internet some interesting project that called interactive wall. My kids so exited about it. So i decided to give them a challenge to make some equal projects.

Here is the inspiration : https://scophy.wordpress.com/2008/01/15/art-tuesd...

And this tutorial shows you how we build an interactive led art from designing the circuit until arranging 1000 sensors to detect shadows and turn on the LEDs

The key of this project is a dark sensor. We use Light Dependent Resistor (LDR). It sense the present of light (luminosity of light) and change it into resistance. The resistance of a photoresistor decreases with increase in incident light intensity. To make this project easier for my kids to understand, so i made it as simple as possible. But they can learn a few things :

• Power Supply (in this case, a battery)
• Electricity
• Energy convertion (from electricity to light)
• Simple mechanical sensor (switch)
• Light / dark sensor (photoresistor)
• Polarity (battery and LEDs)

Based-on that goal, so i decided the battery, photoresistor, and the LEDs should be plugable.

Create a 3D model will helps you to review the product before production. So here the render images of this model. To create this 3D model is quite easy when you use Autodesk Eagle. You just need click push to Fusion 360, and your 3D PCB are set. If there is missing 3D components, you can add or import on Fusion 360.

If you're interesting this 3D model, please take a look my grabcad model : https://grabcad.com/library/glow-in-the-dark-pcb-...

Bill of materials this circuit :

• 1x CR2032 battery holder
• 1x coin battery cell CR2032
• 1x pre-wired photoresistor
• 2x 5mm Green Super Bright LEDs
• 2x resistors (220 ohm)
• 1x Potensiometer (100K)
• 1x NPN Transistor
• 1x On-Off Switch
• 3x Female headers 2P

After finalize the design and exporting to gerber files. You just need to send it to a PCB manufacturer, like JLCPCB, PCBWay, or other PCB manufactures.

Actually the assembly process is quite easy. All soldering parts is done with hand-soldering. But it need a lot of patience to assembly a thousand units. I spend about 2 weeks to assembly all the pcbs.

Now is the fun part. My kids help me arrange the sensors, which is totally a thousand sensors.

1. Insert the LEDs
2. Insert the photoresistor
3. Insert the battery
4. Turn-on the switch
5. Put on the table

Yap, they do it with patience. After all sensors installed, they plays with it.