Note: Do not connect high-power electrical appliances, otherwise accidents will occur due to
improper use!
How do we safely use high-power appliances, do you know how to control the elevator? In fact,
it needs an automatic control system, in which the relay plays an important role in helping us.
This system guarantees our electricity safety by controlling large currents with small currents.
In this lab, we will learn how to use relays to build an automatic control system for controlling
motors.
Experiment 10 – Automatic control
Instruction
Learn how relay works and use it to control the DC motor with switch.
Micro:bit x1
Crowtail-Base shield for Micro:bit x1
Crowtail-Relay x1
Crowtail-Switch x1
Crowtail-Cable x2
DC Motor x1
USB cable x1
Jumper Wire x1
Target
Required Parts
The Relay is the most commonly used module in some actual applications such as home
automation, and sometimes you need to control large current such as the air conditioning/water
heater. That is what this Large Current Relay Module can help with.
The connector of the relay module has three sockets: common (COM), normally closed (NC), and
normally open (NO). COM: common pin. NC (Normally Closed): the normally closed configuration
is used when you want the relay to be closed by default, meaning the current is flowing unless
you send a signal to the relay module to open the circuit and stop the current. NO (Normally
Open): the relay is always open, so the circuit is broken unless you send a signal to close the
circuit.
This Large Current Relay Module is a high-quality Single Pole Double Throw Relay(SPST). When
the relay not triggered, the 2 outputs are disconnected; when the relay triggered(Logic Low), the
2 outputs connected, the max current can be up to 30A@240VAC or 30A@30VDC, which would
be enough for most of the home appliances.
Hardware learning and connection
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