User Manual

28
Lesson 8 Reed Switch
Introduction
A reed switch (as shown below) is a sensor used to detect the magnetic field. Hall sensors
are generally used to measure the speed of smart car and count products on assembly lines.
Reed switches are often used to detect the existence of magnetic field.
There are two reed switches in this kit: reed switch and mini reed. They work in the same
principle.
Components
- 1 * SunFounder Uno board
- 1 * USB data cable
- 1 * Reed switch module
- Several jumper wires
Experimental Principle
A reed switch is a type of line switch component that realizes control by magnetic signals. It
induces by a magnet. The “switch" here means dry reed pipe, which is a kind of contact
passive electronic switch component with the advantage of simple structure, small size, and
convenient control. The shell of a reed switch is commonly a sealed glass pipe in which two
iron elastic reed electroplates are equipped and inert gases are filled.
Normally, the two reeds made of special materials in the glass tube are separated. However,
when a magnetic substance approaches the glass tube, the two reeds in the glass tube are
magnetized to attract each other and get touched due to the magnetic force. As a result,
the two reeds close the circuit connected with the nodes.
After the external magnetic force disappears, the two reeds will be separated with each
other again because their like poles are placed near which intend to repel them apart, thus
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