Tutorial 02

Light Sensors

1.0 Introduction

Photodetectors (sometimes called photosensors) are sensors of the visible portion of the electromagnetic spectrum or other electromagnetic radiations [1]. 

Classified by mechanism of detection, photodetectors may be grouped into but not limited to:

• Photoelectric (e.g. CCD digital camera sensors, object detection sensors in manufacturing, … )

• Photovoltaic ( e.g. cells in solar panels )

• Semiconductor based (e.g. ambient light sensors, … )

2.0 Ambient Light Sensors

These photodetectors sense the amount of ambient light present, measured in lux. The common types are photoresistors, photo diodes, photo transistors and photodiode amplifier modules shown below [2]. 

2.1 Ambient light sensor on Codey Rocky

The following image shows the location of the ambient light sensor on Codey Rocky.

3.0 How it Works

4.0 Programming with the Ambient Light Sensor

4.1 Using Codey to measure the ambient light 

NB: The learners could move around different places with different light intensities, including the outside, to experiment

4.2 Actions that can be achieved by the application of the ambient light sensor 

For gaining valuable experience, practice more with scenarios of your own creations. Enjoy! 

References

[1] https://en.wikipedia.org/wiki/Photodetector

[2] https://www.edn.com/making-sense-of-light-sensors/

[3] Basic Coding Course (Tang, 2016)