In the previous chapters, we have seen different projects on home automation and domestic that is control and monitor home appliances. In this chapter, we will give some ideas to develop some projects that they can be done in different areas using electronics, controlling and monitoring.
As its name implies, the Light Dependent Resistor (LDR) is made from a piece of exposed semiconductor material, such as cadmium sulfide, that changes its electrical resistance from several thousand Ohms in the dark to only a few hundred Ohms when light falls upon it, by creating hole-electron pairs in the material. The net effect is an improvement in its conductivity, with a decrease in resistance for an increase in illumination. Also, photosensitive cells have a long response, time requiring many seconds to respond to a change in the light intensity.
In this section, we will look at how to use a light sensor to control different...