For my first real project I'm trying to control a 12v wiper motor using an Arduino Uno plus an Arduino motor shield Rev3. The shield instructions suggest separating the power lines of the shield and the Arduino board on which the shield is mounted by cutting the "Vin Connect" jumper placed on the back side of the shield. I have questions:
So I just use cutters to remove the "Vin Connect" pin? I hesitate to vandalize my board, so I'm just making sure.
I can then provide 12v via the 2.1mm jack on the Arduino and in addition provide 12v across the "Vin" and "GND" terminal screws on the shield? I'm trying to use a single 12v power supply for simplicity.
I'm including a pic of the pin in question just for clarity
Arduino motor shields are carrying a dinosaur L298 motor driver, which is only capable of 1Amp continuous and 2Amp peak. A poor choice for a wiper motor that can draw 5-6Amp continuous and 10A or more peak. Have a butterfly net handy, to catch the escaping magic smoke.
A mosfet module (not the IRF5xx-type) sounds like a much better solution.
Assuming you only want to turn the motor in one direction.
Leo..
No
You cut the trace with a knife along the red line (see image)
If you want to go back to using just one supply you can put a blob of solder across the two pads to remake the connection
Hmm, this is something I didn't consider. Is there a shield available that uses MOSFET, or a fairly simple way to add a MOSFET module to a shield? I can assemble electronic components, but I'm not knowledgeable enough to design anything yet.
I think what @Wawa was referring to was using a different shield/board. polulu.com has a good selection, just read carefully and choose a MOSFET driver. Driver boards connect differently from shields, so be aware.
Shields are typically only for tiny toy motors.
The chips on them are rarely capable of driving a wiper motor.
Shields and motor driver modules are typically H-bridges, meant to drive the motor both ways.
Wiper motors typically only turn one way, where the mechanism provides the oscillating motion.
If only spinning one way is required, then a simple mosfet module is a better solution.
Leo..
How do you know that the motor shield you have won't work, did you try it?
How do you know the the new one will work?
You may be wasting your money for nothing.
I didn't try it, because the specs say (now that I've read them carefully) that it can handle way less current than my motor draws and I don't want to destroy it. The new one I ordered is spec'd to handle a lot more current.
I'll find a use for the old one, and the extra money is in my budget.
A Halloween project. I've got a coffin with a hinged lid; the lid is connected to a wiper motor that my Arduino will make open and close rapidly to simulate something inside that's trying to get out. If I can't reverse the motor then the lid has to open to the limit of the linkage every time, rather than just lifting an inch or so.
It now makes sense that you have ordered a motor driver.
Because only a H-bridge can reverse the motor.
A simple mosfet (one direction) would have been the wrong choice.
Leo..
I don't, really. But I estimate around 3-5 amps because it's a windshield wiper motor from a Mercedes and it's pretty beefy. The Arduino motor controller maxes out around 1 amp.
Certainly the best method - but hobbyists with a suitable relay and a couple of limiter micro switches in their junk box could tackle the project differently. As I did with my curtain controller that’s still working 20 years later.
