74HC138 (3 to 8 Line Decoder- Demultiplexer) ESP32-CAM The adder logic

The adder logic

With a simple three serial SPI interface

The lens used here is not really doing much and so we see that the two slots can 'see' out past some distance (basically the sensitivity of the sensor)

Data acquisition systems

the range from  2cm to 400cm

74HC138 (3 to 8 Line Decoder- Demultiplexer) ESP32-CAM The adder logicIntroduction : The 74HC138 decodes three binary weighted address inputs (A0, A1 and A2) toeight mutually exclusive outputs (Y0 to Y7). The device features three enable inputs (E1, E2 andE3). Every output will be HIGH unless E1 and E2 are LOW and E3 is HIGH. This multiple enablefunction allows easy parallel expansion to a 1 of 32 (5 to 32 lines) decoder with just four '138 ICsand one inverter. 74HC138 can be used as an eight output demultiplexer by