The IR detector circuit in principle, converts the IR signal pulse trains into noticeable aural notes. S1 is used to switch on/off mains power and LED1 indicates power-on. Resistor R4 and zener diode ...

Team creates LEDs, photovoltaic cells, and light detectors ... conventional diode materials, "so you'd use thousands of times less material" to make devices of a given size. In addition to the ...