Connecting a LDR sensor
We are going use a LDR - Light Dependent Resistor - as an example about how to connect a resistive sensor to our instruments and control them.
A LDR is an electronic component whose resistance decreases with increasing incident light intensity. Photoresistors come in many different types. Inexpensive cadmium sulfide cells can be found in many consumer items such as camera light meters, clock radios, security alarms and street lights.
We call resistive sensors those ones that need a pull-up resistor to be connected to the circuit. The schematic is:
Connect your sensor to the "SENSOR" pin headers and solder a resistor in R1.
"R2" pin headers enbable you the option to include another resistor and vary the initial voltage range.
"OUT" pin headers are:
1 -> 5 Volts
2 -> Vout
3,4 -> Ground
Photos:
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