The LED photodiode circuit operates in three steps, with control provided through the microcontroller and a C-based software routine

Download PDF

Other Materials from the Main Document

• Article «Single LED Takes On Both Light-Emitting And Detecting Duties»
• Figure 1. A standard LED, connected to a pair of microcontroller bidirectional I/O pins with a high-impedance capability, can act as a photodiode to detect light intensity
• Figure 2. The LED photodiode circuit operates in three steps, with control provided through the microcontroller and a C-based software routine
• Figure 3. With greater light intensity on the LED, the decay time (T_D), during which the voltage on P1 discharges, is shorter (a). The voltage on P2 goes high if T_D exceeds T_DCR (b). These are experimental results using a 5-mm, high