Introduction: LED It Grow

This instructable is done for the TUDelft course TCD from the faculty Industrial Design. This light is made to stimulate the growth of plants and so making urban farming more accessible to the greater public.

Step 1: Step 1. What Do You Need?


  • Arduino uno Neopixel Jewel - 7 x WS2812 5050 RGB LED with drivers
  • 3 Electric wires of approximately 20 cm each
  • Round aluminum bar for turning - height: 50 mm, diameter 45 mm
  • 1 mm thick PETG plate- 40 x 40 mm
  • Bison tix glue
  • Isolation tape


  • Solder equipment
  • Turning lathe
  • Laser cutter
  • Arduino programme
  • Illustrator

Step 2: Step 2. Turning the Housing

To make the housing you need some experience with turning aluminum. The sizes are illustrated in the given picture. Follow these steps:

  1. Put the aluminum piece in the lathes claw with 10 mm fixed
  2. Start with turning the outside diameter to 40 mm precise for a length of 35 mm
  3. Drill a hole of diameter 14 mm, 35 mm deep
  4. Drill a hole of diameter 30 mm, 25 mm deep
  5. Turn the inside of the housing to obtain a wall thickness of 8 mm to a deepness of 27 mm
  6. Turn the inside of the housing to obtain a wall thickness of 5 mm to a deepness of 25 mm
  7. Turn the inside of the housing to obtain a wall thickness of 3 mm for a deepness of 1 mm
  8. Smooth all the edges and polish the full housing but especially the inside to increase the light reflection.
  9. Separate the the first 30 mm of housing from the piece of aluminum that is still in the claw. Do this carefully to not damage the housing.

Step 3: Step 3. Laser Cutting Diffuser

The diffuser is made of a PETG plate of 1 mm thick. Follow these steps:

  1. Start with sandblasting the translucent plate on both sides. I used glass powder for this.
  2. Make in illustrator a circle with a diameter of 34 mm
  3. Upload the file to the laser cutter and laser cut the circular shape

Step 4: Step 4. Assembling the Electronics

The 3 electric wires have to be soldered to the Neopixel LED ring like shown the picture. After this connect the wires to the Arduino board and connect the Arduino board to the computer.

Step 5: Step 5. Uploading the Code to Arduino

Use the following code in Arduino and upload it to the Arduino board:

#include #ifdef __AVR__ #include #endif

// Connect to pin 6 on the Arduino #define PIN 6

// The number of pixels on the neopixel ring #define NUMPIXELS 7

Adafruit_NeoPixel pixels = Adafruit_NeoPixel(NUMPIXELS, PIN, NEO_GRB + NEO_KHZ800);

int delayval = 500; // delay for half a second

void setup() {

pixels.begin(); // This initializes the NeoPixel library. }

void loop() {

// For a set of NeoPixels the first NeoPixel is 0, second is 1, all the way up to the count of pixels minus one.

for(int i=0;i

// pixels.Color takes RGB values, from 0,0,0 up to 255,255,255 // Fill in the RGB value below here from 0 to 255 // The best combination of light is when only the Red and Blue LED's are turned on pixels.setPixelColor(i, pixels.Color(255,0,255 )); // Purple light.; // This sends the updated pixel color to the hardware.

delay(delayval); // Delay for a period of time (in milliseconds).

} }

Step 6: Step 6. Assemble the Grow Light

  1. Glue the Neopixel LED ring into the housing with the Bison glue and let the wires go out the hole at the bottom
  2. Wrap the wires with isolation tape if necessary and connect the wires to the Arduino
  3. Glue on the diffuser plate by using a minimal amount of glue.
  4. Connect the arduino to a powersource and place the light close to a plant to stimulate its growth