CoffeeBot monitoring with Arduino
With a nod to one of the original Internet connected devices (The 1991 Trojan Room coffee pot) Engineer Patrick Fenner decided to monitor the DoES Liverpool coffee pot from the next room over using an Arduino.
A set of bathroom scales lives underneath the coffee machine in the kitchen, connected to an Arduino Ethernet that measures the weight, calculates the number of cups of coffee in the machine and sends the data out to Xively.
All the measuring electronics of the scales has been bypassed and the Arduino measures the mass of the water in the coffee machine by reading resistance change from the strain gauges at each corner of the scales, via an INA125 instrumentation amplifer.
Detail on connecting the instrumentation amplifier to the Arduino is shown in the ArduinoInstAmp repository in GitHub