My Reef pi build - Well, my Viparspectra PWM light controller :D

[ph123uk]

Well got it all soldered and connected, just need to run 8 wires to the control boards on my lights, thought i'd test reef-pi UI and set it up.

All working but no idea how to add lights or configure my relays to test....doesn't seem to be anything to select at all or do I have to now learn some scripting languages to make a relay turn on?

 

[ph123uk]

Ok, managed to add both relays and set up timers for on and off for both channels! - awesome - now need to work out how to control them!

 

[ph123uk]

Doesn't work adding a jack for Pi PWM 18 and 19 - keeps giving me an error - any help? (error, failed to create, invalid pin 18)

 

[ph123uk]

In case anyone reads this pin 18 should be 0 and pin 19 should be 1 - this let's you add 2 new Jack's to utilise the in built pwm of the Pi through reefp-pi

 

[ph123uk]

Going to try and get this connected to the light this week, 4 core cable ordered!

Couple of pics of this super simple build so far.

 

[ph123uk]

Quick question for anyone viewing, I am getting an "Undervolt error" when I turn on the reef-pi, the convertor is converting from 19.4v to 5.1v according to my multimeter - any ideas?

 

[ph123uk]

Another question maybe if @Diamond1 could help?

My lights require an ON/OFF and a 12v - now my 19.4v PSU is converted down to 5.1v and soldered to the PI HAT - Do I NEED 12v to go to the light? if so Im gonna have to split the PSU input to two and have 2 separate buck convertors?

 

[Bigtrout]

Quick question for anyone viewing, I am getting an "Undervolt error" when I turn on the reef-pi, the convertor is converting from 19.4v to 5.1v according to my multimeter - any ideas?

Where is your uln2803? That I think is your problem. You are trying to run the relays directly off of the raspberry pi outputs which draws too much current thru the pi output pins causing the undervoltage error. The uln2803 is part of the power controller for a few good reasons. It isolates your pi outputs from the relay board AND it handles the higher current relay power draw using only minimal current thru the pi output pins. In effect it "amplifies" the raspberry pi outputs so that you can run higher current items.

 

[ph123uk]

This is how I was told to run the reefpi - the relays are 5v ones - should I use another convertor and run the relays at 12v? will this damage them? - Cheers for the reply - I'm only using it at the moment for light control (or will be when I get it connected up) this is how I have it set up (minus the feeds to the lights so far)

 

[Bigtrout]

This is how I was told to run the reefpi - the relays are 5v ones - should I use another convertor and run the relays at 12v? will this damage them? - Cheers for the reply - I'm only using it at the moment for light control (or will be when I get it connected up) this is how I have it set up (minus the feeds to the lights so far)

No the relays run at 5 volts. The problem is each relay uses 72 milliamps of current. The pi outputs only handle 15 milliamps safely. Its not the voltage, its the power draw on the pi.

Read the reef pi power controller section. The uln2803 chip is the key here. You send your pi output signals to the uln2803 which acts like a mini relay to turn on the relays. The uln2803 can handle the relay current, whereas the raspberry pi outputs can not.

 

[ph123uk]

So would this fix it?

 

[Bigtrout]

That may work...im sorry I didnt see that your relay boards have the opti isolators so, the uln2803 isnt needed. If your usinv a pi3 it may need all the output of one of the buckpucks just to run, so powering the relay board seperately would help.

 

[ph123uk]

Im super confused now - I went back through @Diamond1 thread and my original way was how I had it set up! I probably shouldn't be doing this....

https://www.reef2reef.com/threads/reef-pi-build.482170/page-18

So how has he sent a 12v to his driver to turn it on!?!

 

[Bigtrout]

Dont panic..lets troubleshoot what you have so far.
If you you unhook the relay board, do you get the undervoltage alarm?

 

[ph123uk]

actually, ive just re-scanned and it was all explained to me once!

https://www.reef2reef.com/threads/reef-pi-build.482170/page-28

So I don't need to change anything, except this is causing my low voltage message :/ - the 12v comes from the fixture itself, so I don't need to add that, the relay is just switching it

What I may need to do to solve my error - if I'm understanding this correctly it simply run a separate buck convertor, also down to 5v, directly to the relay, instead of going through the Pi - will remove the relay and see if I get the error message!

 

[Bigtrout]

Thats what we need to troubleshoot the low voltage message.
Unhook the relay board...just try runnung just the pi with the puck...with only the pi hooked to the buckpuck do you still get the message?

 

[ph123uk]

Ill give it a blast when I'm home tonight (currently at work) - cheers Bigtrout

 

[Bigtrout]

No problem!

 

[ph123uk]

Even with the relay unplugged im getting an undervolt error :/

 

[GK3]

Even with the relay unplugged im getting an undervolt error :/

Disconnect everything from the pi...both relays and the pwm signal to the lights. See if the pi will power on without error this way. This will help eliminate a bad pi being the cause.