The Danger of Having a Nice Hammer...

...is that everything starts to look like a nail.   My hammer of choice, as you can tell from this blog, is the Arduino microprocessor integrated with various electronic sensors and relays and packaged in something 3D printed.

In this case it was a mod for my new 3D printer.  The new printer is an enclosure which makes it particularily nice for handling ABS which I have not been successful in doing with my open Prusa I3.  What this enclosure does is trap heat inside it which is what you want for ABS...just not for PLA.

Now I can take the cover off the printer, and leave the door open, when I print PLA but I wanted something a little easier than popping the cover on and off.   So enter the below configuration:

Two fans connected to a relay that will turn them on and off but also connected to an Arduino Nano for speed control.   Relay driven by the Arduino Nano, however, if the Nano is not present then the fans will run controlled by the on/off switch. DHT-11 temperature sensor also connected to the Nano.  Arduino Nano enclosed in my Projects Platform.   All of this gear wrapped into a custom designed chunk of 3D printed panel that replaces one of the side panels in my printer.  This panel features cutouts for the fans, power outlet, on/off switch, and a place where the Arduino Nano/LCD Projects Platform can be slotted.  The panel also as a little electronics bay for the relay, a power regulator  (12v to 5v), and the various connections.   You may be able to see this but there are also wire tie downs printed on the panel.

I had all the hardware assembled and had started on the software.  It would function in either a simple on/off mode but more importantly in a mode that would trigger on a certain temperature threshold being hit.   Fans would run at different speeds depending on the temperature deviation.

Somewhere in the process of putting all of this together it occurred to me that all I really needed was some positive airflow while printing PLA or while cooling ABS down for removal from the build platform.   In other words, all that was needed was this simple panel and a cheap fan:

Not nearly as much fun!   Bit it meets the requirement just fine! 

In the end I did decide that the least that I could do was to use one of the fans that I had already bought so the final cofiguration has the below insert as the cooling option: