An udderly awesome Smart device for smarter milk consumption.
No milk for my tea/coffee
Not knowing if I need to pick up milk when I’m at the store
If I Googled health risks… (I’d probably find out I’ll die due to underconsumption)
World Wide Milk Epidemics
The Smart Milk Tracker Device
Got Milk? Backend Service (Hue, Relay, Wunderbar integration)
Got Milk? Frontend UI
Got Milk? Spark Firmware
Got Milk? MQTT Mock Server
Since we gave up on hacking the Bosh digital scale the "digital" way, we opted to lobotomise the thing and just add our own ADC. However, this comes with an entirely new set of problems: reading the tiny resistor changes of load cells requires some analog circuitry. Not or strongpoint at all.
The first issue: all the load cells in the scales seem to have 3 wires. Somewhere in the back of our head we remembered something called a Wheatstone Bridge. However, all the load cells in the fancy drawings just have 2 wires. Where is that 3rd wire coming from?
Luckily, the internet always provides the answer. The 3rd wire is used to compensate for wire resistance. Using this knowledge we where able to draw up a simple schematic of how we should connect the load cells.
The original plan was to use a grove ADC and the bridge Wunderbar module. However, due to problems with the module's firmware, we had to improvise an other way of digitising the analog signals.
We opted to use the Spark Core we brought with us, and transfer the data to the Wunderbar using UART.
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