Thread: LED Grow Light
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Old 02-24-17, 07:46 AM   #9
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Originally Posted by jeff5may
To control the brightness, the DIM pin is used. For a single board, a resistance can be connected to pull the pin low. The chip has an internal 5VDC supply that runs the current sensing circuitry and the switching output. The DIM pin is tied to this 5V reference through a 200k ohm resistor. A 250K potentiometer can be connected between the DIM pin and ground to control the brightness.
I looked at the drivers last night. They do have the 4115 chip on them, and the DIM pin (pin 8) is not connected. I ordered a cheap 250k pot from Ebay, for a $1.50. Once I get it, I will experiment with the dimming functionality a bit.

Originally Posted by where2
Nice how-to, and Quite a bit less expensive than a typical AeroGarden. On an AeroGarden, you raise the lamp as the seedlings grow in order to maintain light intensity relative to the seedlings leaf canopy.
Thanks, I hope it can help someone. Initially, my "dimming" will simply be only powering 1 LED COB at a time. If I need more I will just simply power more. As you can see what I am discussing with jeff5may, I may be able to dim the LED COBs with these exact driver boards with an external pot, which would eliminate the need to raise the grow light.

Originally Posted by switchingtosolar
Would getting LEDs from aliexpress be reliable?
I don't see why it wouldn't be. I have ordered 2 things from AliExpress and have had 0 issues. Me personally, I tend to order more stuff from Ebay because their search engine is better at finding exactly what one needs without going through all of the dross.
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