Beer temperature tester using EFM32 Giant Gecko development kit

Answering the question of life, universe and everything – What is the temperature of the beer?

This project was conceived during after-hours on the roof of our office in Nydalen, where we were sitting in the sun splitting a case of beer. The problem was that the sun was heating the beer and in order to minimize the heating of each beer, we wanted to know which beer in the case was hottest and thus was the next in line to drink. A second specification for the automatic beer-case was that we wanted an alarm going off whenever a beer was about to get too hot for drinking, so we could down it immediately.

We therefore bought 24 LM35 Precision Centigrade analog temp-sensors and mounted them on top of some insulation-material (dish washing sponges) in the bottom of the beer case and routed all the wires back to an EFM Giant Gecko Development Kit. The code was put together during an afternoon and is mainly a patchwork of the graphics examples with some ADC-readings thrown in.

Please enjoy some pictures of this wonderful creation, readily awaiting the next “conference call”.

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The finalized project


Close-up of the display, written using the glib graphics library


The temperature sensors, mounted on the dish washing sponges

As this was done just three weeks after we first started at Energy Micro, the source code is pretty low standard, but we’ve attached it anyways. Aaand for the moment, you have to do the differential equations in your head.

Here are also the schematics for wiring up the first 8 temperature sensors: SCHEMATIC1_Now,and a link to how we are going to wire up the next 16: SCHEMATIC1_Next

Stay classy.
Audun & Alf

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This Hack a Gecko project is a result of a “fun hacking session” and are provided as is, free of charge with no guarantees or support from Energy Micro, to partially or fully show and demonstrate EFM32 Gecko microcontroller capabilities. Get inspired, use at own risk, and build some awesome and cool applications.”

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