Arduino Micro as Fan control?

[AmazingSpanoMan]

Hello all. I'm still fairly new to arduino, really the only experience I have had with it is connected to the RAMPS board on my Prusa. Anyway, I'm trying to figure out if the project I'm thinking about tackling is even possible before I go and purchase the parts. It may seem a little silly and I don't really need to do it for any reason other than I want to see if I can.

I have a new Printrbot metal simple and even though I've messed with the POT current the extruder motor overheats. I'm not the only one with this issue but I did find that running a fan (that I mounted to the printer) on the motor prevents the stepper from overheating resulting in skipped and no extrusion. Right now I have a 12V fan connected directly to the power source which means that it is on as long as the printer is on. I could put a switch on it but the purpose of this printer is to bring and show at schools to promote 3D printing and I want to keep it nicely packaged, pleasing to look at and as automated as possible.

Here is my question. I see on adafruit these temp sensors and began thinking... I wonder if I can use a arduino micro to read temp from the sensor attached to the side of the stepper that will kick a fan on when a certain threshold is met I could have a fully automated fan system for the stepper and not have to unplug the printer when I'm not using it. I know the arduino is 5V so do I need a different fan or is there something I can do with the mini that will activate a 12V relay that powers on the fan essentially keeping the draw of powering a fan off the board? I'm looking at the mini because of its small form factor which will be easier to mount into the underside of the printer. I'm also wondering how I can power the mini. is there a way to piggy power off the 12V adapter and get it to output 5V for the mini? I don't care about speed control a simple full on or full off is fine for the fan control.

I've done a google search on this but I keep finding speed control etc not with the mini which is not really what I'm looking at. I'm looking at also using the mini to power some RGB LEDs to coincide with the temperature of the hot end (if that's possible)

Thanks!

[adafruit_support_bill]

You can use a DC/DC converter to get 5v for your Mini. https://www.adafruit.com/product/1065
Then use a transistor to allow the mini to switch current to the fan: https://www.adafruit.com/product/756
If you connect the transistor through a PWM port, you can control the speed of the fan too.

[AmazingSpanoMan]

You can use a DC/DC converter to get 5v for your Mini. https://www.adafruit.com/product/1065
Then use a transistor to allow the mini to switch current to the fan: https://www.adafruit.com/product/756
If you connect the transistor through a PWM port, you can control the speed of the fan too.

OK great! Now here is my next newb question. Obviously these parts don't get attached to the micro and would need their own board. What is the easiest way or the next step after testing this via a breadboard that will allow me to be as compact as possible? Should I go to something like 123D Circuit and set it up/order a pcb? (if that's even possible)?

thanks!

[adafruit_support_bill]

A custom PCB would definitely get you the most compact board. Other options would be one of the smaller perma-proto boards. These let you transfer your circuit directly from the breadboard (same layout). If you like, you can trim the board down to just the part you need for your circuit.

https://www.adafruit.com/products/1171

[AmazingSpanoMan]

That looks like a good alternative. Just because I'm curious and I never did it before what is your recommendation for creating a custom board?

[adafruit_support_bill]

For small runs, 123D s good. Fritzing Fab does a nice job too, but shipping can be expensive if you are not in Europe.

[AmazingSpanoMan]

How do you feel about using the Adafruit trinket 5V instead of an arduino Micro?

[adafruit_support_bill]

For something that simple, the Trinket would be ideal.

[AmazingSpanoMan]

Very good! Thanks for the help!