How to power a project (24v LED and 12vFans) from one source

Other Hardware Home Automation
1

Hi, this is my first project. I'm not good at designing yet. I did all the tutorials for Arduino, but they all run on 5V. Now I need help.

Project: use Arduino to control a cabinet's grow lights 24V and 2 computer fans on 12V.

What I thought I would do is use the power supply of the lights, which is 24V, then splice in parallel to a Buck Step down converter to 12V (10 to be safe?) and then branch parallel that one to the Fans and the Arduino breadboard Buck Step down converter to get my 5V to power the Arduino.

Then I would use the TO-220 MOFSET to control the speed of the fans and intensity of the lights. I was going to use relays, but that's on / off only.

But my main question is, can I splice in the power brick output like I described?
24V -> 1x 24 + (1x buck down to 12V -> (12V + 1x buck down 5V))

Thanks!

2

Please post a wiring. Your home cooked formula might be misunderstood.
Use logic level N channel MOSFETs for the fans. TO220 is the housing of the transistor and MOSFET is the name for a wide range of mos transistors.

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Thanks for answering. The MOSFET I found so far are: N-channel power MOSFET - 30V / 60A. Might be overkill, so I'll be looking at something closer to my parameters.

As asked, I did a quick diagram in MS Paint (must be a better way) of what I'm trying to power. I assume common ground, but it's not depicted. MOSFET are also omitted as they are not really in question or not necessary in order for this to work.

powersource
powersource1023×293 29.3 KB

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Thanks! Exactly the wiring I would like to see. That must be okey. One alteration could be to power the "to 5 volt buck" from the 24V DC source. That lovers the risc for ripple affecting the stability/quality of the 5 volt to the controller.
Note that MOSFETs must be of the logic level type! Large voltage and amp capacity fets needs a gate voltage of some 10 - 15 volt to turn on fully. You only have 5 volt from the nano.

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Ok, so you're saying 3 parallel power is better than my drawing. The only reason I was going from 10-12V, is because I thought I would use the one that comes with the Arduino kits that are 7-12V. I'll just have to buy one that does 24V to 5V, they are smaller anyway.

Last question, do I do everything common ground to the 24V ground? Or do I keep them ground to the Buck converters' ground? I thought common ground...

And thanks, yes the MOFSET need to operate at 5V and under.

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For ground, use a "star topology" where all grounds are connected at a single point as close as possible to the 24V power supply.

1 Like
7

Use the stuff You've got! It's most likely good enough.

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