LED Umbrella For Grass

Dave Clausen

The problem:
Grass dies without strong sunlight.

The solution: Construct a grow light that doesn't consume a lot of power, doesn't block the natural sunlight, and produces natural-looking colors.

Step 1: Solder up strings of red, green, and blue LEDs:

Step 2: Arrange them in an umbrella shape, fed at the center, with the outer ring acting as a ground:

Step 3: Build a 3 channel step-up power supply using an AVR ATMega48, 47 µH inductors, IRLU3715 mosfets, TC4427A mosfet drivers, and other miscellaneous parts. The buttons are for adjusting the brightness of the red, green, and blue channels. I thought I would use this to fine-tune the color balance, but in practice I don't use them:


Click for unlarge

Step 4: Using the laser cutter down at the nerd club, make a case for the power supply and a base for the umbrella.

Step 5: Apply electrons:

Step 6: Install the device and plant new grass seeds:

Step 7: Enjoy your non-dead cubicle grass:

Sourcecode, SVG files for the laser cutter, and Eagle schematic are here.

dclausen.net