How to connect the MCU with L298N and relay? When to choose L298N or relay module?

L298N module

The main control chip is L298N dual H-bridge motor drive module, the drive voltage is 5~35V, generally drive the DC motor forward and reverse generally use L298N.

Wiring pin

VCC: There are one 12V port and one 5V port. For example, to control a 12V DC motor, connect the positive pole of the 12V power supply to the 12V pin.
GND: Connect the negative pole of the battery to this pin, and also connect the GND of the microcontroller to this pin.
ENA/ENB: enable port, only when ENA port is high level, IN1, IN2 can be used, when ENB port is high level, IN3, IN4 can be used.
IN1/2/3/4: Control port. 1/2 controls OUT1 voltage output, and 3/4 controls OUT2 voltage output together. Such as: IN1=1, IN2=0, output ports OUT1 and OUT2, output positive voltage, the motor rotates forward, otherwise the motor reverses; IN3, IN4 are the same.
OUT port: directly connected to the motor, 12 groups, 34 groups.

Relay module

As a switch, it is used to control large current with small current, like the electromagnetic door lock can use the relay module as a switch. Although the use of relays to control the forward and reverse rotation of the DC motor can be achieved, it is more complicated and requires two relays to be cross-connected.

Wiring pin

DC+: Connect the positive pole of the power supply, for example, to control a 12V load, connect the positive pole of the 12V power supply to this pin, and the negative pole to DC- (the voltage is 5V.9V.12V and 24V according to the requirements of the relay).
DC-: Connect to the negative pole of the power supply.
IN: The control signal input terminal can control the relay pull-in at high or low level, and the single-chip microcomputer control can set the relay module to low level control.
NO: Normally open interface of the relay. The relay is suspended before the relay is closed, and shorted to COM after the relay is closed.
COM: Relay common interface
NC: Normally closed interface of the relay, the relay is short-circuited with COM before pull-in, and hangs up after pull-in
When the last three ports are not input at IN, NC and COM are short-circuited. When IN input is high or low (see whether it is set to high or low), COM and NO Short.