Maelstrom Reef Pi

[AbjectMaelstroM]

Alright boys, we're in business. Relay works (short 12 and on/off). PWM dims down to 1% without flicker!

 

[AbjectMaelstroM]

Now I gotta figure out where I'm going to stick these relays....

 

[devlzluv]

Woot woot!!!

 

[AbjectMaelstroM]

Ok so, this is how I'm thinking of dealing with these lights. Adding x4 channel 12v relay into the main Pi box so that it's a short run from the pi to the relays and close to the HAT light plugs. To work one fixture I need 8 wires, perfect for CAT5E: 2xPWM(HAT), 2xGND(HAT), 2x12v(relay), 2x on/off (relay). Connect all 8 wires to an RJ45 plug, then wire a "mirror" RJ45 jack in the fixture, then finally, link the two with CAT5 cable.

This is my test-bed:

Just tested it and everything seems to work great!

Now, my only concern is the wire thickness of CAT5 and current on the line. Would this be OK for something like a 6 ft run?

 

[Michael Lane]

Looking great! I would bet there isn't much current, so I probably wouldn't be worried. I'd be surprised if it's above a few milliamps total.

 

[devlzluv]

Lol omg im more confused now than ever

 

[AbjectMaelstroM]

Lol omg im more confused now than ever

It's actually not as hard and messy as it looks, I'm actually a little upset it took me this long to get to this point.

Anyway, in its current state my setup requires 8 wires to go to the fixture, I'm using CAT5E.

I'm using Mike's HAT, a 4 channel 12v relay (you can use 5v, I'm just using 12 because I'm activating the relay using the UNL2893A on the HAT.

Each fixture has two drivers inside with a 4 pin plug each (GND, PWM, 12v,ON/OFF). All you need is a PWM, GND, 12v and ON/OFF for each plug. PWM and ground comes from the HAT and 12v and on/off comes from the relay output. This is copied over for the second driver for total of 8 wires.

The way it works inside the pi:

In connectors create two outlets and two Jacks (I named them Vipar1Blue and Vipar1White for the blue and white channels). Outlets are tied to IO pins 22 and 23 on the UNL2893A on the hat. The two Jacks get pwm pins 13 and 14 from the HAT Pca9685. So to put it all together, using equipment in Pi, turn on the appropriate outlet (ie Vipar1Blue), which activates the relay by closing the circuit on 12v and in/of, which turns on the blue channel driver and fan. From that point you use the lights controls within pi to adjust channel brightness 1-100. You can dim to 0 but they still stay on (very dim), so to fully turn off the channel you have to toggle the equipment off on that channel.

I'll try to make a diagram when if I get some time tonight or tomorrow. But there is a thread linked above where the guy did pretty much what I'm doing, but without Mike's HAT.

 

[AbjectMaelstroM]

So, tomorrow I'm wanting to put the final build of the pi together. Before I finalize the layout.... Can two buck converters be powered from a single power supply?

I need 5v for the pi and 12v for the lights (ULN2803a). I have an extra power supply (15.6v@7A) from my toughbook, could this be used to run 2 buck converters (I guess in parallel), one stepping down to 5 and other to 12v? Really don't want to run two power supplies for the box.

 

[Michael Lane]

You can run multiple buck converters from a single power supply.

 

[AbjectMaelstroM]

First fixture is done.

Ditched the rj45 for aviation connectors....much easier to drill clean round holes than square.

 

[AbjectMaelstroM]

So this is my final build. Lights, temp, pH and outlets are built in. Got some room left for ATO and doser to be added later, had to get a bigger box to allow more room for the 4 relays for the lights. Plan is to use Kasa power strip for any additional outlets I need.

Little messy inside. Going to try clean it up a bit but it's not going to be a ton cleaner. Good news, it's going to be on the back of the equipment cabinet so it s out of sight.

 

[hockeyhead019]

Good call on the cannon plugs! It looks way cleaner. I have the same light rig and am hoping to get the same end result but I'm using a pi hat from @theatrus so I think I'll have to do some extra work to push that on/off bit to the light. I think I would be ok leaving the 12V and ground from the original light right?

 

[AbjectMaelstroM]

Good call on the cannon plugs! It looks way cleaner. I have the same light rig and am hoping to get the same end result but I'm using a pi hat from @theatrus so I think I'll have to do some extra work to push that on/off bit to the light. I think I would be ok leaving the 12V and ground from the original light right?

Not quite sure what you mean by "ok leaving the 12V and ground from the original light".

Sorry, been a long day.

 

[Michael Lane]

Good call on the cannon plugs! It looks way cleaner. I have the same light rig and am hoping to get the same end result but I'm using a pi hat from @theatrus so I think I'll have to do some extra work to push that on/off bit to the light. I think I would be ok leaving the 12V and ground from the original light right?

You might need to be a bit careful with that. I don't think the picoboard exposes the PWM output based on page 6 of the schematic. It seems to smooth out the PWM and convert to a 0-10v analog signal. A voltage over 3.3 volts could potentially damage your light.

The ground line will need to be tied into the rest of the system in order for it to understand a pwm input signal.

 

[hockeyhead019]

You might need to be a bit careful with that. I don't think the picoboard exposes the PWM output based on page 6 of the schematic. It seems to smooth out the PWM and convert to a 0-10v analog signal. A voltage over 3.3 volts could potentially damage your light.

The ground line will need to be tied into the rest of the system in order for it to understand a pwm input signal.

This jives with what I found after reading into some of the info more.