Mini fridge build part 3

With most of the components installed in previous steps, it’s a case of bringing in al the parts and connecting them to Forebrain.

Pictured above is actually one of my MK5 Forebrain prototype units (http://www.universalair.co.uk/), hence the colour, lack of silkscreen, and the fact that all the components were lovingly soldered by hand. The bit of stripboard on the left holds the potentiometer for the LCD’s contrast input, however it turns out that the best setting for this is all the way down, so it would have been sufficient to tie the LCD’s contrast pin to GND.

Connecting the PT100 temperature probe:

I’ll supply the code at some point if anyone requests it.

A hole is drilled through from the back electronics compartment all the way through to the inside of the fridge for the PT100 probe. All the gaps are sealed up with RTV sealant.

Finally, the whole shebang is perched on top of the fan at the rear, with a hole in the side cut for the USB port. Since I neglected to install any buttons (and the buttons on Forebrain being unavailable), the only way I am going to control this fridge is via USB. This will perhaps become the world’s first USB mini-fridge.

Oh, one last thing – because I am going to fill the inside of the fridge in water, I need to have the fridge stand on it’s back. Because the air intake is at the back, I need to stand it off with something. This turned out to be as simple as transplanting its rubber feat from the bottom to the rear.

Ready for action…as soon as I get around to programming the code for it…

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