3.1.1 Analog Light Sensor

The Analog Light Sensor outputs a current dependent on the amount of light the Sensor is exposed to. The current is fed into a resistor creating a voltage which can be captured by the ADC.

The Sensor Controller uses the peripheral Timer 2 to enable power to the analog light sensor around 1 ms before the Sensor Controller will wake up to take a measurement. If the light level is higher than a threshold, the Sensor Controller will wake up the System CPU for processing of the measurement. This will repeat with a frequency of 10 Hz. The example is tested with the same ambient light during the whole test period.

Figure 4. Analog Light Sensor: One Measurements

Figure 5. Analog Light Sensor: Average Current Consumption