scurvyrat

Thank you. Love tinkering with this stuff. I'm going to spend a bit of time tracing the PCB traces and see what I can figure out a bit of the schematic. Here are two shots of the D120 board that was in my fixture: Not a whole lot there. Would be good though to see the various models that are out there.

Update: I am driving 3 Nova A8s, which would be 12 LED drivers all from 1 PWM pin on the Reef Angel Dimmer Expansion. Works fine. Some of the banks are brighter than others at low PWM signals and I think that is more to do with adjustments on each driver. Works great. I've started looking at my D120. I have the same rheostat dimmer board as show by AlanM except I have two connectors on board, but only one used. Otherwise, the pot looks the same: I opened up the driver, labeled as Well-LIT LT-PCB-9076C. There are a bunch of connectors. Counting up from the bottom, connected to the Rheostat board are +12V VR-SW2 VR- VR+ I measure 9.78V on the VR-SW2 when the light is on. Note two connectors, not connected: D-GND VDIM+ Here is the underside of the PCB: So, my first thought was I might be able to dim off the VDIM+ pin. Unfortunately, that pin just connects to JP1 and JP2. Also, when the light is on, I read 2.24V on VDIM+. All the ICs have their labels sanded off. There are very few components which are not soldered on the board, so I'm hoping that the circuitry that can take the PWM signal is all there. Does anyone have any suggestions on how best to proceed? I'm a little nervous to close JP1 and JP2 and wire it up, but it might come to that...

Ooops -- forgot about that. Thanks for the clarification. If I measure the duty cycle they are spot on and the same. Still unclear why one of the whites would be brighter than the other since they are wired together. Ditto for the two blue drivers. Seems to clear up when the voltages get a bit higher, but that also might be just because its harder to see the difference visually. When I opened up the driver there is a small POT that maybe is adjusted different between the two? Either way, they dim up and down and are under full control of the Reef Angel which was the hope.

I've been monitoring the voltages on my setup today and I'm getting some odd results. I have it wired from the Reef Angel 0-10V PWM Dimmer expansion. Pins 1 & 2 are short-circuited together. This represents +12V and On/OFF. Pin 3 is the PWM and Pin 4 is Ground connecting the Reef Angel ground to the driver ground. There are two banks of lights each with a white and blue channel -- so in total there are 4 LED drivers. I've got both blue and both white channels connected together so making only 2 channels for now. At low PWM signals ( < 2V) One bank is noticeably brighter than the other. ie: the left bank is brighter than the right bank, meaning one blue and one channel are brighter than the other ones. Reading the PWM signal, there is about +0.5V more on the wire than what the PCA9685 is putting out. For instance: PWM Measured 1.8V -- 2.33V 2.0V -- 2.525V 3.40V -- 3.87V 4.61V -- 5.0 4.92V -- 5.28V As you can see, the difference is decreasing as the PWM signal goes up. Not sure what is putting more voltage on the line. Any ideas? I did measure 10.77V on the on/off pin when the factory dimmer was installed. I'm feeding it 11.78V which is what the +12V pin reads. Not sure if that is involved or is an issue.

Forgot to mention that for the Arduino you'd need to boost it to 0-10V PWM instead of 0-3.3V or 0-5V. I'm going to probably use the dual LM358 which the Reef Angel is using.

correct, they are 0.1" pin headers. Just want to see if I can match up to what they are using.

here is the top of the board. There are two connectors and two boards since there are two rheostats on each unit. Each board connects to two Well-Lit LED drivers. As you can see on the pic of the bottom of the board, each connector is simply jumpered together. I have it dimming via the Reef Angel and the PCA9685 PWM chip. Since there are 4 LED dimmers (2 blue and 2 white) you can have 4 channels of dimming and stagger the channels to get better lower levels of light at the far ends. Just want to make some boards up with the same connectors so I don't have to cut the wires on the drivers and can leave the existing boards in place. Not really necessary, but makes undoing the mod a 2 second job. Another option is to put a small arduino powered off the +12V and create a wireless dimmer. I may go that route just for fun. Last year, when I had more time, I made an Arduino compatible board with the RF12B transceivers. You can see them here: http://scurvyrat.com/2011/09/15/ruby-v1-0b/ and http://scurvyrat.com/2011/08/06/bejouled-ruby-v1-0a/ They are based on the Jeenode boards. Should be cake to wire one of those in to the light. Then I can send wirelessly from the Reef Angel to set the dimming.

I have the Evergrow Nova A8s. I purposely got the lights with rheostats instead of their fancy controller to save $ and also to hook it up to my Reef Angel. While the dimmer board is more complicated (It has what looks like a 12V PWM generator), the same mod works fine -- short pins 1 (on/off) and 2 (+12V) and then supply 0-10V PWM on pin 3 and tie the grounds on pin 4. I would like to make some jumpers and little boards without cutting off the connectors from the LED drivers. Has anyone found which 4 pin connector these are using? The connector that AlanM shows on the top of his dimmer board is the same as on mine. On the Nova A8 there are 4 LED drivers per unit -- 2 for blues/2 for whites -- or whatever colors you have mixed in. Appears you can then do 4 different channels per Nova A8. Here is a pic of my board: