My Pi test-bed dates back to the first Pi I got 2012, upgraded with each new release of h/w. Other than the Pi the only other change in that time has to modify the mounting when Pi’s with mounting holes first arrived on the scene !

The room I work in gets very hot in summer so with all the discussions around how hot the new Pi4 gets I decided to add a DIY fan ‘hat’. I probably should have made this on the 3d printer but as I had some plain prototyping board to hand it seemed a good idea to show how a very cheap ‘no complicated tools needed solution’ could be made.

I started by cutting out a 65mm x 55mm rectangle of prototype board, using the Pi as a template I then marked out and drilled (with a 3mm bit) the 4 corner holes.

The fan I used came from ebay, it is a 12v 40mm PC fan costing about £2.50. Here I am running it from 5 volts, while this means it will run slowly it does have the advantage is that is effectively noiseless.

Next I marked out the positions of the fan mounts a main cut out. Lastly using the Pi as a template again marked out the cutout for the PI header.

Prototype board can easily crack, to reduce this risk I made sure the cutouts followed the  matrix hole positions and then used a 2mm drill to ‘extend’ extend them. I could have been a bit neater doing this but it worked out ok. Any ridges I carefully filed down with a needle file. The tip here is to make sure you support the board on a flat surface.

Lastly I mounted the fan on the board with four 2mm nuts & bolts. To attach the ‘fan hat’ to the Pi I used 10mm spacers from ‘stock’.

The fan came with a 2 pin connector that I connected directly to 5V and Gnd on the Pi header.

The fan does not seem to move much air but importantly it ensures a continuous ‘disturbed’ airflow over the main chips on the Pi. With a room ambient of around 25C the Pi processor temp sits at 44-45C (Pi lightly loaded), disconnecting the fan this went up to 65C within a few minutes.

With a bit of extra filing I could improve access to the header pins but as I mainly use this Pi for s/w development my need to access the header is limited.