Analog Ambient Light Sensor

Description

Datasheet

The sensor can detect illumination either direct glare or indirect reflection. The field of view is 360 degrees which is suitable for ceiling or wall mount application. Place the sensor in a suitable location with line of sight to areas where illumination should be detected.

The sensitivity can be adjusted with a simple jumper position. This selection changes the gain of an analog amplifier. Choose a gain suitable for typical brightness. A high gain will detect lower brightness levels. Whereas a lower gain will minimize noise in the signal.

The output mode can be changed from a continuously varying analog signal to a digital signal. The digital signal is produced by a comparator with a threshold at half scale (i.e. 5V) or quarter scale (i.e. 2.5V). Use the analog mode to continuously monitor lighting levels. Or use the digital mode to trigger actuators at a specific event threshold.

Changing the sensitivity and choosing the digital output scale can adjust the event threshold. Setting sensitivity high and digital scale low will reduce the event threshold to a minimum and detect the smallest changes in brightness. Whereas, setting sensitivity low and digital scale high will increase the threshold to a maximum and detect only the largest changes in brightness such as glare.

Detection Level 

The light detection level can span many orders of magnitude. Choose an appropriate range for the typical brightness at the installation location. Indirect illumination can be a small fraction of actual illumination on work surfaces. Whereas glare can be many times larger than actual illumination. Some understanding of these differences is important to accurately detect the lighting levels in a space.