New to reef-pi basic question

[CarissaT]

Hi,
I want to set up a automatically dimming LED system for my freshwater tank and I've done some reading on using the reef-pi to do this but I'm a bit stuck on one point. I'm using basic 12V LED strips, and the logic signal coming from the raspberry pi will be 3.3V, so what's the simplest solution for interfacing between them? I'm planning to have 6 channels.

I looked at this, but it's not clear what the input signal voltage needs to be on it?
https://www.aliexpress.com/item/32989911253.html

Or this, but same question...would input voltage from the raspberry pi work directly or need to be modified?
https://www.aliexpress.com/item/32901054008.html

Or is it simplest to just build my own MOSFAT board?

 

[Ryan115]

Do you know how much current you will be using on each channel?
If it is less than 500mA per channel you may be able to use a darlington transistor array to run all of it.

Individual transistors or MOSFETs would work as well.

 

[Bigtrout]

Hi,
I want to set up a automatically dimming LED system for my freshwater tank and I've done some reading on using the reef-pi to do this but I'm a bit stuck on one point. I'm using basic 12V LED strips, and the logic signal coming from the raspberry pi will be 3.3V, so what's the simplest solution for interfacing between them? I'm planning to have 6 channels.

I looked at this, but it's not clear what the input signal voltage needs to be on it?
https://www.aliexpress.com/item/32989911253.html

Or this, but same question...would input voltage from the raspberry pi work directly or need to be modified?
https://www.aliexpress.com/item/32901054008.html

Or is it simplest to just build my own MOSFAT board?

WELCOME to Reef2Reef!

For simple dimming of 12v strips, read my build thread, I bought some mosfet modules on ebay that would work for you.

https://www.reef2reef.com/threads/my-reef-pi-build-freshwater-style.531338/page-8

 

[CarissaT]

Perfect! The MOSFET boards are exactly what I need. For my main lighting channel it could be up to 2 amps. What I’m planning is:

Channel 1: two 1m strips of 6500k (as bright and dense LEDs as I can find) might go up to three strips depending on how bright the strips actually are when I test them. I’m just getting cheap generic LED strips for now of a couple different kinds to try out.

Channel 2: 3500k single strip use for sunrise/sunset and potentially along with the main lights if more brightness is needed.

Channel 3,4,5, 6: r, g, b, ww - strip to use for sunrise/sunset and moonlighting.

Once I get this all working my next project will be adding on a pH probe to regulate co2.

 

[Ranjib]

Welcome to reef2reef and thank you for considering reef-pi.
Checkout the second circuit for power mosfet based circuit, it targets a typical 12v led strip: https://learn.adafruit.com/reef-pi-lighting-controller/circuit-construction all you need is a logic level power mosfet and a 1K resistor.
Pi can only provide two pwm output, so you'll be limited to onlt two independently controllable signal, i.e. if you want to contrrol all 6 channels independently, use the pca9685 ic .
godspeed

 

[Ranjib]

@CarissaT how is your build coming? Let us know if you need any help