PWM Heating element controller

Hi there.

Given that it's coming into winter here in Australia, and I really hate being cold, I decided to install DIY heated hand grips/heated vest on my motorcycle.

My idea was to use the arduino mini/pro mini to drive some sort of MOSFET using PWM to control the temperature for each handlebar and heated vest independently. Each heated grip will be ~25W(1.9A @ 13.5V), and vest will be ~75W(5.6A @ 13.5V).

I need advice on whether there is an available shield or commonly available module that would work with these 3 separate heaters?
After doing some reading, I found the PWM pins on the arduino are fixed at ~490Hz? Now from my rather limited knowledge on MOSFETs, I believe that I might have issues with the MOSFETs dissipating a large amount of heat when switching at this sort of this the case?

Alternatively, is there a kit/schematic with component part number for something like this?

I want to use the arduino for a basic display of temp, rpm, speed etc.. on the bike anyway, hence the reason for using it in this project also, rather than a separate PWM module. Plus, it's just cool! (excuse the pun)


I googled for "arduino mosfet driver" and came up with a number of results including (6 outputs) and N-MOSFET Driver / Output Module | Freetronics (1 output). Neither is perfect. The Sparkfun module doesn't have a series resistor to limit the gate charging current to 40mA or less. The Freetronics module does have a series resistor, but its value is rather large (1K, where I would have used between 100 and 220 ohms), also the resistor to ground is not in the right place (the top end of it should go to the other side of the series resistor).

490Hz is quite a low PWM frequency, so the mosfets will dissipate very little heat unless you use a very large value gate series resistor.

Here's a nice 4-FET switch board that might be good:
And there is some example of using it here: (The rest of that page shows relay control of power etc..)
DISCLAIMER: Mentioned stuff from my own shop... (That's what I know about and have tested myself.)

That Power FET switch board is also Opto-Isolated and this may be an advantage in a vehicle environment..

Let us know how this works out. I'm from Vermont USA and I have thought of adding a seat warmer for my wife who will be going to work on those -20F mornings. I want her Subaru (sitting in the barn with the trickle charger plugged in the back so she can just drive out) to have an Arduino that gets the seat warm just as she gets out to the car :slight_smile: There aren't that many ways left to be a hero at my age...

Meanwhile she knows I'll be sitting 15 feet above the wood stove in my loft with my computer and all my Arduino stuff and sensors, and getting on these forums...

That's next Winter; this year we are in sunny (usually) Italy on the Mediterranean with a nice bottle of Barbera (1.9 Euros).