Reef Pi Build

ph123uk · Jan 22, 2019

Hold on, are the relays 12v or 5v - earlier in the thread you put 12v relay, but the above seems like its 5v?

Think i'm going to give this a pass sadly, too many components with voltage changes and things I simply don't understand! - thankyou for the effort though, the more I read the more confused I get so probably not a great iea for me to be messing with my only light!

Doesn't help that im in the UK and most components you linked aren't readily available e.g the relay is this one - without a "high / low" - whatever that means, that your link has

https://www.amazon.co.uk/ELEGOO-Channel-Optocoupler-Arduino-Raspberry/dp/B06XK6HCQC/ref=sr_1_6?s=electronics&ie=UTF8&qid=1548153511&sr=1-6&keywords=5v+relay&th=1

Edit: Its also going to cost £60 ($78) (and I already have the pi)

I cant understand why if the Pi has PWM control, I cant just splice into the PWM wire/s on the light and use the pi to control that

(and keep everything else inside my light unit)

Diamond1 · Jan 22, 2019

You can use a regular wall wart power supply, just make sure it's a 2.5 amp.
I used one of these https://www.amazon.com/SD-15B-5-Pow...&qid=1548164987&sr=8-8&keywords=meanwell+15-5
The meanwell is much more stable and has more than enough to run the pi and relays.

Diamond1 · Jan 22, 2019

ph123uk said:
Hold on, are the relays 12v or 5v - earlier in the thread you put 12v relay, but the above seems like its 5v?

Think i'm going to give this a pass sadly, too many components with voltage changes and things I simply don't understand! - thankyou for the effort though, the more I read the more confused I get so probably not a great iea for me to be messing with my only light!

Doesn't help that im in the UK and most components you linked aren't readily available e.g the relay is this one - without a "high / low" - whatever that means, that your link has

https://www.amazon.co.uk/ELEGOO-Channel-Optocoupler-Arduino-Raspberry/dp/B06XK6HCQC/ref=sr_1_6?s=electronics&ie=UTF8&qid=1548153511&sr=1-6&keywords=5v+relay&th=1

Edit: Its also going to cost £60 ($78) (and I already have the pi)

I cant understand why if the Pi has PWM control, I cant just splice into the PWM wire/s on the light and use the pi to control that (and keep everything else inside my light unit)

I started off using 12v relays but switched to 5v relays.
The problem with running without the relays is powering on the fixture and the fact that the drivers are not dimmable to 0%. The drivers start off at 10% when powered up via the relays then the pwm controls the ramping from there. You should be able to use any 5v 2 channel relay it doesn't have to be the ones I linked. I'm not sure about the vipraspectras but my OR t247 doesn't have enough room inside the fixture for adding the components inside.
@Jonathan Troutt modded his Viprspectras to use with reef-pi maybe he could say if there's enough room inside.

These relays would work just fine and cost 3 pounds.
https://www.ebay.co.uk/itm/5V-1-2-4...aaf76edcb:m:mdbiogK3bG3MfWb_sjDpLvw:rk:2:pf:0

Diamond1 · Jan 22, 2019

I do understand if your not comfortable taking your only light apart. I have a couple of back up T5 fixtures I used on my tank while I was testing and modding.

ph123uk · Jan 22, 2019

Would this PSU be ok? - looks similar

https://www.ebay.co.uk/itm/DC-DC-15...cecaab335:m:m3hi4-38kkRQltV2dluTDvw:rk:1:pf:0

Diamond1 · Jan 22, 2019

ph123uk said:
Would this PSU be ok? - looks similar

https://www.ebay.co.uk/itm/DC-DC-15...cecaab335:m:m3hi4-38kkRQltV2dluTDvw:rk:1:pf:0

Looks like it would work just fine, but you would still need another 12v dc power supply to match it's input requirements. You really don't need anything more than a good 5v 2.5 amp power supply to run the pi and relays. I just used the meanwell because I have 18 relays in my set up and wanted a stable power supply.

ph123uk · Jan 22, 2019

So I need 2 power supplies? - like I said getting more and more confused here.

Diamond1 · Jan 22, 2019

The power supply you linked requires a 12v power supply to convert power from 12v to 5v. The power supply I use requires 110v and converts that to 5v.
If you want to simplify everything you can just use a raspberry pi power supply to run both the pi and the relay and not worry about the meanwell. That gets you down to 1 power supply for everything.

ph123uk · Jan 22, 2019

So in my case I need a PSU which converts 230v to 5v - ok, I think I get that - as in mains power converted to 5v for powering the Pi and most other ancillaries.

Or I could get a 230 - 12v PSU and use a buckpuck dialled down to 5v - which also makes me able to use the PSU for other items too? e.g. A 12v Led strip or similar

Did I grasp that correctly?

ph123uk · Jan 22, 2019

Or I could use a Laptop power brick with a buckpuck on it to dial it down? (have loads of laptop power supplies)

ph123uk · Jan 22, 2019

Or I could get one of these, cheap as chips!

https://www.ebay.co.uk/itm/DC-3-3V-...5d27d655:m:mIyCjxxccLr0U9g_A2WAAVg:rk:24:pf:0

or this

https://www.ebay.co.uk/itm/2-x-DC5V...001d165c:m:mBlQBseWTyCGaqL0GuWXAfA:rk:27:pf:0

(if I have it right?)

Diamond1 · Jan 22, 2019

This one in the 4 amp configuration would be great. https://www.ebay.co.uk/itm/2-x-DC5V...001d165c:m:mBlQBseWTyCGaqL0GuWXAfA:rk:27:pf:0

ph123uk said:
So in my case I need a PSU which converts 230v to 5v - ok, I think I get that - as in mains power converted to 5v for powering the Pi and most other ancillaries.

Or I could get a 230 - 12v PSU and use a buckpuck dialled down to 5v - which also makes me able to use the PSU for other items too? e.g. A 12v Led strip or similar

Did I grasp that correctly?

Correct. It all depends on what you want your unit to control.

crusso1993 · Jan 22, 2019

Diamond1 said:
This one in the 4 amp configuration would be great. https://www.ebay.co.uk/itm/2-x-DC5V...001d165c:m:mBlQBseWTyCGaqL0GuWXAfA:rk:27:pf:0

Correct. It all depends on what you want your unit to control.

BTW - these units will not control your wife/girlfriend. We are still working on a model for that but do not expect any results soon! ;Jawdrop

;Jawdrop

ph123uk · Jan 22, 2019

Impossible, nothing controls my wife....shes a strong independent woman..... till she needs shoes.

Diamond1 · Jan 22, 2019

Here is the basic circuit construction I used to control my lights. GPIO 18 and 19 are the Rpi pwm channels and I used gpio pins 20 and 21 to control the relays. The relays are powered from the 5v rail on the right side of the PI hat. The grounds from the light are actually run from the ground on the 5v rail not the 3.3v rail.
In the second pic ignore the buck converter. I used that during testing, the actual power for the pi and relays comes from the meanwell 5v PS.

The wires in the circuit are:
Blue = GPIO 20 & 21 that control the relays
Yellow = GPIO pins 18 & 19 that control pwm to the lights
Black = Ground from the lights
Black and Red (twisted) is the 5v power supply to the relays
Black and Red on the right is the power supply into the board from the meanwell. This supplies power to the pi and the relays.

Bigtrout · Jan 22, 2019

Diamond1 said:
You can use a regular wall wart power supply, just make sure it's a 2.5 amp.
I used one of these https://www.amazon.com/SD-15B-5-Pow...&qid=1548164987&sr=8-8&keywords=meanwell+15-5
The meanwell is much more stable and has more than enough to run the pi and relays.

I agree with this fully, I was using wall warts and under load I could watch voltage waver so I went with 2 of the meanwell rs-15-5 and the voltage stays right where I set them and stays steady.

crusso1993 · Jan 22, 2019

Bigtrout said:
I agree with this fully, I was using wall warts and under load I could watch voltage waver so I went with 2 of the meanwell rs-15-5 and the voltage stays right where I set them and stays steady.

Hard to beat a Meanwell for the money...

Ranjib · Jan 22, 2019

Bigtrout said:
I agree with this fully, I was using wall warts and under load I could watch voltage waver so I went with 2 of the meanwell rs-15-5 and the voltage stays right where I set them and stays steady.

That is very interesting. Thank you for sharing, I have some known gremlins in couple of my builds , I’ll re-analyze them from this perspective

Bigtrout · Jan 22, 2019

Ranjib said:
That is very interesting. Thank you for sharing, I have some known gremlins in couple of my builds , I’ll re-analyze them from this perspective

@Ranjib
The problem with most wall warts is, who made them, can you look up specs? With most you can not other than what printed on them. I suspect that most wont put out a good steady voltage at their rated current.
I am a service engineer for a high end cnc machinery company, and their machines only use 2 brands of power supplies, IDEC and Meanwell, if they trust them for critical machinery, I trust them for my aquarium

That being said, the mountable power supplies have much better specs, but if you are having trouble with a build that would be hard to change from a wall wart, Meanwell makes some wall warts with good specs, but they are relatively expensive compared to the RS line of power supplies. Most branded laptop plug in supplies are good but then you need to step down with an lm2596.

At first I used Samsung 5v 2amp wall warts because they were laying around. Upon testing with just a pi zero, and 8 relays on a relay board all powered on, I watched voltage dip from 5.1V to 4.85V. And it would fluctuate while turning relays on and off. The meanwell stayed at 5.099V no matter what I did.