There's a tripwire — made up of a laser directed at a light sensor ... an LCD monitor to the setup and change the code to display the waste level on the LCD instead of just the Arduino ...

Whereas a typical scale would then simply show the resulting number on an LCD display, [Mirko] decided to use a moving coil meter driven by the Arduino ... with any analog sensor, calibration ...

We love the concept of using an LCD screen to transfer data ... takes measurements from the light sensor which is held in front of a Macbook Retina display with different backlight levels.