ROARduino - A power-board

40mA per channel not enaugh for you?

Try ROARduino! Use any pin - with any Voltage! And lots of Power!

The idea behind this, is to create an Arduino clone that has transistors attached to each pin, so you would indirectly control any load. Providing the possibility to use a jumper to switch between a power supply you're running the arduino with and a completely external supply with any Voltage (depending on the transistors though).

So what do you think?

I could see the potential for both a shield and a clone.

Personally, I wouldn't get the clone, but I'd consider getting the Shield (or at least etching one myself :P).

Does it exist?


I've thought about this, mostly in connection with Arduino-like board based on newer processors with weak outputs (5mA or less), rather than the AVR's rather nice 20-40mA.

The problem is that you start running into a long list of issues that are difficult and expensive to deal with:

  • "any voltage and lots of power" ? Doesn't exist. There are always limits.
  • Did you want to source AND sink current? Now you're talking about a half H-bridge per pin (3 transistors, typically) rather than one transistor.
  • Wait, did you also want to be able to float the outputs so you could do stuff like Charlieplexing? That would mean ... Um...
  • what about being able to do input on some of those pins?
  • How BIG is this going to be, once you allow for the heatsinks needed for all those high-power transistors?
  • So how much does all that cost, per pin? And how much are you paying for the pins that don't actually need that high-voltage, high-current, driver?

Nope, doesn't yet exist.

Thanks for the thoughts westfw,

  • True but compared to the rather limited output power anything is a lot ;-), I mostly thought of 5 to 12V Output, maybe 15 for some DC/Stepper-motors. considering amperage, at least 500mA per Output but I'd sure like 1A being able to drive some of the higher power LEDs und some decent motors.
  • Good point, but for the first prototype I would just source the pin, In my experience as an intermediate-level Arduino user I only need the abbility to source it.
  • ...float the outputs? don't know what charlieplexing is (yet) but I would certainly provide the possibility to access the pins without using the transistor.
  • see above
  • quite large actually... so I think I'd rather go for a shield...
  • as less as possible :slight_smile: didn't think about the price yet... will be taken into consideration as soon as my first prototype is ready

As far as I'm concerned the shields main purpose would be to ease the use for experimenting... It always bothered me to solder around just for trying one or another motor/LED/Laser/Water-pump...
So it should be as cheap as possible as it would only be something making your life easier but not adding any additional functionality.

However making this shield for the arduino pro mini would be great, so you could implement it in your finished projects.