RGB's are beautiful and fun to play with. However, to drive them requires some type of modulation circuit or micro-controller such as Arduino. I have been racking my brain for months to find a simpler solution because I have an Innovation Education Center for kids and I wanted something that the Mini Makers (under 7) could build and experiment with....finally...one of my daughters experiments provided the inspiration for a solution.
She made the first two prototypes. They worked, but we kept refining the design. And after 5 prototypes, we have created the world's simplest RGB LED driver. It's range is not as good as PWM...but what it lacks in range, it makes up for in simplicity! It can produce a decent range of beautiful colors. And its fun to experiment with on different fruit and moisture levels. Give it a try.
- A Citrus Fruit Peel (the thicker and larger the peel the better)
- RGB LED (common cathode)
- 9 volt Battery
- 1k Resistor
- 6 Alligator Jumpers
- 1 Metal Chopstick (or a conductive rod of some kind)
Step 1: The Fruit Peel Preperaration
This is the most important part of the experiment, the fruit peel preparation.
1 Carefully take the peel off the fruit. Keep as much as you can in one piece and shaped with 3 legs.
2. Let it dry out for a few hours.
3. Soak it in water for a half a day.
Start this process first and then go work on the circuit.
Step 2: RGB Circuit
It's beautifully simple!
- Put a 1k ohm resister on the common cathode of the RGB and jump it to the negative 9V battery terminal.
- Attach the R,G,B LED anodes to jumpers and then to different corners of the fruit peel. Experiment with different locations and distances.
- Then attach a jumper to the metal chopstick (or any conductive rod) and the other end of the jumper to the positive side of the 9V battery. Note: you can use more than one positive electrode. For example is you wanted a strong purple (one on red and one blue)
It should look something like this...