1. 1 Lab3 – Optical Sensor

2. 2 When a light path is interrupted and when it is completed, the AVR records both events. Uses typically include counting objects such as highway toll stations or events such as computing RPM’s of a rotating shaft with a “blade” that interrupts the light path every 1 or ½ cycles.

3. 3 Lab3 – Optical Sensor When the NTE3100’s light path is not blocked it produces +5V at Vc. R1 is a current limiting resistor. Resistor values may differ in different manufacture lots. Choose the resistor values by measuring I c

4. 4 Lab3 – Optical Sensor

5. 5 One Design Example of the Optical Sensor Notice: In this design, PA0 is used to receive the input PB0 is used to light the LED7

6. 6 Hardware design is given except proper selection of resistor values Software design needs to support (1) a start button (2) a stop button (3) a reset button to reset counter (4) counter recording number of objects blocking the light. (5) a heartbeat signal on LED0 (6) LED7 toggles when a block is detected.