Mars Aqua led light

[lotus02]

Mars Aqua led light I have 5 of them want to make them dimmable with a Raspberry pi.
will a PCA9685 16-channel 12-bit PWM servo driver do this or do i have to convert to analog for it to work.
I tried the reef-pi setup for Kessil leds and the light will not dim I wired the lights the way they say to for the apex reef controller wired the on/off with GND made a cat6 cable for VDM - & VDM+ to go to the breadboard will not work.

 

[Big G]

@saltyfilmfolks

 

[saltyfilmfolks]

@Ranjib @reeferfoxx

 

[Michael Lane]

I've done this with a bunch of Mars Aqua lights. I probably went overboard, but in general, you need to provide 0-10v analog signal for dimming. The Mars Aqua lights don't dim to zero, so I also used a comparator to shut them off below their threshold. I can pull up the schematics if you are interested.

 

[Ranjib]

I've done this with a bunch of Mars Aqua lights. I probably went overboard, but in general, you need to provide 0-10v analog signal for dimming. The Mars Aqua lights don't dim to zero, so I also used a comparator to shut them off below their threshold. I can pull up the schematics if you are interested.

@Michael Lane so, 10V pwm wont work? do we need an RC circuit or a full blown DAC?

 

[lotus02]

I've done this with a bunch of Mars Aqua lights. I probably went overboard, but in general, you need to provide 0-10v analog signal for dimming. The Mars Aqua lights don't dim to zero, so I also used a comparator to shut them off below their threshold. I can pull up the schematics if you are interested.

yes if you could that would help.
i just check and the pca9685 is not changing the power staying at 10v and i change the sd to a new loaded reef-pi and still no change so pca9685 not working or some think not right on breadboard.

 

[lotus02]

Should say something not right on beardboard. I have a voltmeter on the cat6 cable and it stays at 10v no change when i change the light setting on reefpi

 

[lotus02]

so i think I have it working now but the fan runs slower the lower I have the light dimmed and it makes kind of buzz or ring sound I think it coming from the fan, the fan stops at 15% same with the sound, fan I think is at full speed about 79% and sound stop there too. at 50% sound the loudest

 

[lotus02]

on the dashboard under lights when using the fixed setting for the light it doesn't show anything at all. as to what the light is set at.

 

[Michael Lane]

A simple RC filter should give you what you need. I haven't experienced the fan issue you've described.

Eagle files can be found at https://github.com/Ranthalion/AquariumLED/tree/master/Schematics/MarsAquaAdapter

Here's a couple completed boards (complete with some bodge components too...)

Here's my schematic.

Here's my board layout.

 

[Ranjib]

A simple RC filter should give you what you need. I haven't experienced the fan issue you've described.

Eagle files can be found at https://github.com/Ranthalion/AquariumLED/tree/master/Schematics/MarsAquaAdapter

Here's a couple completed boards (complete with some bodge components too...)

Here's my schematic.

Here's my board layout.

Is this available in your tindie store ? The world needs stuff like this

 

[Ranjib]

Should say something not right on beardboard. I have a voltmeter on the cat6 cable and it stays at 10v no change when i change the light setting on reefpi

This is not right then, were you able to solve this? You should be able to generate almost 0-10 v (in multimeter) with just pca9685 and transistors, if that’s not happening , let’s fix that , step by step

 

[Ranjib]

so i think I have it working now but the fan runs slower the lower I have the light dimmed and it makes kind of buzz or ring sound I think it coming from the fan, the fan stops at 15% same with the sound, fan I think is at full speed about 79% and sound stop there too. at 50% sound the loudest

Are you getting 5v on the transistor base, if you set 50% in reef-pi ui? You should take reading at. Transistor collector pin at 10,20,30,40,50,60,70,80,90% ui values

 

[lotus02]

yes I have it working and the meter is reading it right the Raspberry was not seeing the pca9685 now it is. just have to find what is powering the fans when on the dimmer knob they come on full stay on full on pi the fan is runs same as light 50, 70, 20 where the light is set in reefpi.

 

[lotus02]

so I jumped the V+ with the on/off so that puts the box on than cat6 cable brown wire to VDM+ white/brown to VDM- than cat6 to breadboard.
breadboard has 10v to 1k resistor.
1k resistor jumps over to brown wire and 2N3904 pin 3 (tried a2N2222) same thing happens to fan.
white/brown to pin 1 on 2N3904 to GND
2N3904 pin 2 to 10k resistor
10k resistor to pin 1 on pca9685

light dims but and fan slows down with the light dimming

 

[lotus02]

it was suggested that i add add a 1uF capacitor and change the resistor to a 20K .

I added the capacitor in tried it with the 10K and with 22K resistor as I do not have a 20K and no change with the capacitor fan still not working right.
just not getting the power to the fan.
the power to the fan is the same as the light set reef-pi to 50% for light and fan is only getting 50% just under 6v. I'm think I'm going to have to find a way to change the way the ballast is feeding the fan.

 

[lotus02]

here are some pics of the ballast.
the light will over heat if I can't get the fan running at full speed.
any one have this happen to them with the black-box lights Mars Aqua

 

[Michael Lane]

The fan does expect to either be off, or powered by 12v. I tried a range of intensities and found the same behavior on my lights from 28-30%. The fan is off < 28% and stable >30%. I tested the frequency and it was the same as the pca9685 (1.5 kHz).

That means the filter is not strong enough. I've never noticed this on my lights, but I bet it's just because it only spends a small amount of time between 28-30% intensity.
If you got a multi-pack of capacitors, try adding more of them in parallel. If you are running the pca9685 at 1.5 kHz then 4 or 5 capacitors may fix the problem for you.

It also looks like there may be an error on the breadboard. It seems like the resistor isn't participating in the filter since it's all in the same row.

Try something more like this

Bringing the capacitance up to 4uF should smooth it out much better.
http://sim.okawa-denshi.jp/en/PWMtool.php

 

[Michael Lane]

I decided to test it on my board. That's another beautiful bodge!

The extra capacitance got rid of my problem in the 28-30% range.

I think it's time to redesign that board to fix this issue.
Good luck with yours!

 

[lotus02]

can I run 12v through cat6 cable what I'm thinking is I will just unplug the fans from the ballast and run 12v to them from a separate power supply and have reef-pi switch on relay like this one to turn the fans on before the leds come on. the cat6 has 8 wire so use 2 for each white & blue light and 2 for each fan. I should be able to run the 12 fans 2 in each of the 6 mars lights off one 12v supply through the relay as it's good for 30v DC 10A