Using a usb scale to keep an eye on coffee status at the office
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README

**DISCONTINUED**

Coffeeleft v.3 20110206
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Using a usb scale and a raspberry pi to keep an eye on coffee status at the office. The project will be cleaned up a bit next time I have to upgrade HW/SW.

This project is licensed under the GPL. Contact me if you have questions. I did not make the perl-script, I just modyfied it. See original in references.txt.

https://github.com/ways/coffeeleft


You need
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* one raspberry pi or pc running ubuntu or other linux.
* a usb scale. I used one from stamps.com bought through ebay.
* a coffee pot. Our is a non-transparent, 2 liter, thermo can.
* optional: a LED connected to GPIO
* some spare time.


How-to
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* Install munin, munin-node, apache.
* The .rules file goes in /etc/udev/rules.d/
* Place munin-scale in /etc/munin/plugins/
* Place usbscale-simple.pl in /local/bin/ (create this dir)


Problems
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* The perl script assumes the scale apears as /dev/hidraw0. If you have mouse, keyboard or other devices connected this may be wrong. Change the script.
* Hidraw works differently in ubuntu 9.10 vs ubuntu 10.04. Test with original script, and apply patch in comments here https://gist.github.com/503896 if problems.
* The stamps.com scale has a max weight of about 2.2 kg, the same weight as our empty pot. Fortunately, if the empty pot is on the scale when switched on, the scale is calibrated accordingly, and gives a correct result even though it carries up to 4-5 kg.


References
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* Graphics by Leo @ Copyleft.no
* Usb scale: http://gist.github.com/503896 / https://github.com/erjiang/usbscale
* http://blog.aztekera.com/archives/54