Week 8

The light sensors we used are LDR and single-supply transimpedance amplifiers OPT101 from TI. The light output increases linearly with light intensity. The photodiode has an internal amplifier with a 1MO resistance, which is used when pins 4 and 5 are connected together. Because of this amplifier, we could directly insert the output of the photodiode into the ADC in the MCU. The light sensors go into ports A.1 (inside sensor) and A.2 (outside sensor). We used a 5V regulated input from the MCU. At bright lights, the sensor read up to 4.27V on the voltmeter while getting a .06V when covered upr