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--- projects:fridgehack:writeup [2022/06/08 15:18] – spsmith
+++ projects:fridgehack:writeup [2022/06/08 16:29] (current) – spsmith
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-==== Brass Monkey Fridge Hack ====
+==== Fridge Hack ====
 === Main Article ===
-This story begins with some fridges that had been returned to the retailer for various reasons. \\
-The fridges are Brass Monkey branded and they are retailed through Jaycar Electronics, an Australian\\
-electronics retailer, as well as RTM (Road, Traffic and Marine), an Australian outdoors retailer. \\
-RTM happens to be owned by Jaycar Electronics. The two retailers share some other products between them, \\
-but that's neither here nor there. \\
-Because Jaycar stores couldn't feasibly return the 'dead' fridges to their head office in Rydalmere, \\
-they opted instead to just keep them lying around at their stores taking up space. At some point the \\
-manager got fed up with this arrangement and decided to just leave them outside the shop overnight. \\
-Before doing that however, they irreversibly removed the controller/displays, assuming this would \\
-render them 'unserviceable'. \\
-Enter the crafty sales assistants.\\
-After finding the data sheet for the compressor controllers, it was discovered that the compressors \\
-are low voltage 3 phase units. They have a controller on the side of the compressor body that houses \\
-all the smarts to make it work. It turns out that the displays are nothing more than a thermostat controller. \\
-A simple way to choose set points and so forth. \\
-The data sheet showed us that by bridging pins, 'C' and 'T', we could call for the compressor to start. \\
-That was a great discovery on its own, but the data sheet revealed more. It suggested the controller could\\
-drive the compressor at different speeds! This function was not being utilised in the fridges being sold. \\
-All fridges, as sold, were running at their lowest speeds, 2200RPM, probably in a bid to ensure the fridges \\
-lasted for as long as possible.
-We saw an opportunity to not only get these fridges running, but also drive them to higher speeds to account\\
-for different ambient temps. The higher the ambient temp, the harder it will be for the fridge to get rid of its\\
-heat. This seemed to be a big problem for some customers to get their head around; I saw many fridges mounted\\
-in their vehicles, built into compartments with zero air flow. This is the worst case scenario for a fridge, \\
-particularly when you consider they run at fixed temps.\\
-The controller also had a fault output pin that could drive an LED, with six different faults being displayed.\\
-The faults would be indicated by flashing between 1 and 6 pulses. These faults can be found in the data sheet.\\
-For our purposes, we left this function behind. If the fridge stops running, that was pretty much the end of the line.\\