Action, Sensor Reaction (4)
Often when we build devices we want them to react to the external environment. This means we have to implement some sort of sensor to detect the changes. In this case we’ll build a light detector that brightens according to how much shade is thrown upon it. We’ll need to use a light sensor. This can either be a photo-transistor or a Light Dependent Resistor (LDR). The difference is that a photo-transistor is more reactive in certain levels of brightness closer to the human eye while an LDR has a linear relationship with the absolute brightness of an environment. An LDR is also bipolar, which means that it doesn’t matter which lead you plug into ground and positive, while a photo-transistor has polarity like an LED. ...