!! Working with electricity could always be dangerous, so be careful and protect yourself! If you have no experience in working with electricity learn the basics first.!!

We like growing things. As we want to grow plants like pepper,tomatoes or pumpkins, we have to start most of our seeds indoors. To give them a head start, we built our own cheap LED grow lights to enhance plant growth and to get healthier plants.

3 Challenges:

Cheap:

We searched for the cheapest components with good quality to make our project feasible for a small budget.

Efficient:

LEDs consume much less energy than conventional lights, but that was not enough. We also made sure to use red and blue LEDs with the right wavelength to maximise efficiency

Fanless:

Heat is a big problem for LEDs but because of the usage of a large surface and thermal glue, it was not necessary to mount a fan.

Step 1: Materials

14 x LED RED (650-660nm): (50 pieces quantity) http://goo.gl/s9AR3Z

2 x LED Blue (450nm): http://goo.gl/sgWZDn

4 x LED White (6500K): LED WHITE http://goo.gl/5jwCHt

24 V Power supply 60W: http://rover.ebay.com/rover/1/711-53200-19255-0/1?ff3=4&pub=5575141758&toolid=10001&campid=5337762987&customid=&mpre=http%3A%2F%2Fwww.ebay.com%2Fitm%2FLED-24V-2-5A-ADAPTER-POWER-SUPPLY-60W-%2F141636620626%3Fhash%3Ditem20fa335152

2 x LM2596 DC – DC Step Down Converter: 1 http://rover.ebay.com/rover/1/711-53200-19255-0/1?ff3=4&pub=5575141758&toolid=10001&campid=5337762987&customid=&mpre=http%3A%2F%2Fwww.ebay.com%2Fitm%2F5Pcs-Output-1-23V-30V-DC-DC-Buck-Converter-Step-Down-Module-LM2596-Power-Supply-%2F321476590827%3Fhash%3Ditem4ad97f7ceb

Metal sheet 800mm x 150mm:

Thermal glue

Screws

Cables

= 30€

Tools:

Soldering Iron

Drill

Wire Stripper

Cutter

Solder

Step 2: Idea

Plants do not require the full spectrum of light. The wavelength with the best absorption rate is between 450 - 480 nm (blue) and 650 – 700 nm (red). To save energy, we only use these two colors and just add small quantities of white light (full spectrum). Nobody knows, what the best configuration is and to be sure that our plants get enough light we added these white LEDs. This works fine for us, but you can test your own configuration if you want to.

Step 3: Preparation of the Metal Surface

At first you have to clean the metal sheet and the backside of the LEDs. It is important that the surface is free from oil. therefore, use a bit of alcohol.

Draw helping lines on the metal for the right positioning of your LEDs. This will help you a lot in the next step.

Step 4: Gluing

Use the thermal glue and glue all LEDs to the metal surface. You can stick to our plan or test your own configuration. Do not use too much glue. A thin layer is better than too much glue.

Step 5: Drill the Holes and Place the LM2596

Drill the holes to place the LM2596 as well as one hole in every edge to be to attach the light later were ever you want to. Mount the LM2596 to the surface.

Step 6: Change the Output Voltage (dim) of the LM2596

Solder the power wires to the LM.. Use a multimeter to check the output voltage. One LM should have 19.6V (for blue and white LEDs)and the other one 15.4V (for the red LEDs) You can change the output voltage by screwing the screw on the blue element on each LM2596.

Step 7: Soldering

Do the soldering, stick to the plan. If you have no experience in soldering, please learn the basics first. Otherwise it is possible to harm yourself or the building parts. So be cautious!