Water-Softener Brine-Tank Salt-Level Monitor
If you have hard water, did you ever forget to add salt to the water softener tank? This electronic device monitors how full the tank is using a Sharp DP2D12 infrared distance sensor. The results are displayed on a custom wall plate with a multicolor LED bar graph. The project also includes several photosensors to save power.[read]
IR Detector
An IR signal is “seen” by a reverse biased IR diode which produced an electrical signal according to the light intensity. This signal is then amplified trough a transistor which powers an ordinary LED. This means that the LED will light up when the IR diodes receives some IR light (from a TV remote for instance).[read]