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So, I have a thesis to do where I need to use a Raspberry Pi 3 model B. In the Raspberry Pi, I will need to run a Matlab/Simulink simulation that will give me some results as output. Then I need to take that output and program some kind of PLC, that will communicate with another board using the GPIO output of my Raspberry Pi 3.

My schematic is this: https://i.stack.imgur.com/mI9Ka.jpg

My Raspberry Pi 3 will work as the ripple control receiver in the image. It will work like this: I have 4 digital outputs (D1, D2, D3, D4) that will give me 16 combinations. It will be 1 of that 16 combinations that will be sent to the module on the right (depending on my Matlab/Simulink results).

The problem is that in the port 5, the module is powered up with +12V, and the Raspberry Pi 3 GPIO only supplies 5V. So I will need some kind of converter or relay that will boost my voltage and also feed the other 4 ports (when the respective "switch" is ON, like in the worst case where all the "switch" gates are ON).

So can you guys help me?

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  • 2
    Level shifter and seperate 12V power supply.
    – Steve Robillard
    Sep 19, 2016 at 18:17
  • 1
    Hmm it's the only way? I was thinking in a solution without an external power supply. But thank you for your reply
    – Pirilampus
    Sep 19, 2016 at 18:19
  • You could get a DC boost converter but I think 5 -> 12 V will be pushing the limits, plus it will probably cost more and definitely be "less robust" than a dedicated supply.
    – goldilocks ♦
    Sep 19, 2016 at 18:22
  • Do you think that something like this would work? amazon.com/JBtek-Channel-Module-Arduino-Raspberry/dp/B00KTEN3TM/…
    – Pirilampus
    Sep 19, 2016 at 19:54
  • The Pi is the CPU (brain) Do not power anything using the 5V pins, especially motors? The GPIO are like nerves that send low voltage signals to the muscles. Like Steve said, Level shifter (or transistors) is required to interpret the low voltage signals and the separate 12v is what is going to give you the power. This is how all electronics work and trying to bypass that will just cause you headaches and maybe even small fires coming out of the CPU
    – Piotr Kula
    Dec 6, 2016 at 8:20

2 Answers 2

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The best way would be using MOSFET. For example like this: this

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You can hook the base of a transistor to the GPIO output of the raspberry pi. Here's an example of a raspberry pi controlling a motor:

Diagram

http://www.davidhunt.ie/howto-switching-onoff-a-dc-motor-with-a-raspberry-pi/

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  • That solution will only work with an external power supply of 12V. Or am I seeing the schematic wrongly?
    – Pirilampus
    Sep 20, 2016 at 0:34
  • @Pirilampus well yes an external supply is needed
    – Mohammad Ali
    Sep 22, 2016 at 12:45
  • According to this link, the GPIO of the pi is very weak. 3.3 V, 16 mA. It's only for signaling on or off. You can't power anything off of it. You need an external power supply. raspberrypi.stackexchange.com/questions/9298/…
    – Russell Hankins
    Sep 23, 2016 at 13:43
  • Yes, you must have an external 12v power supply.. Maybe you need to flip the situtaion. If you can only use one power source, then make it 12v and bring down the voltage for the pi using an ubec to 5v. Only power the Pi using that. The 12v with separate power cables to the "motors" - If you can only use 5V... then you have a big problem because ohms LAW is going to kick you in the arse! Again, this are standard electronics principles which you really should read about that first @Pirilampus
    – Piotr Kula
    Dec 6, 2016 at 8:22

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