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Components

5V Relay Module

Electrically controlled switch for lights, pumps, fans and AC-load demos.

Switching Module4.5/5RM4-RM18Intermediate
Arduino ✓ESP32 with suitable module ✓Raspberry Pi with driver ✓
Use Relay Module in my FYPView related FYP titles
single channel blue 5V relay module

AI Ready Overview

Quick Summary

Relay Module is a switching module commonly used in FYP and embedded projects. It is best for pump control and fan control, with wiring and testing planned around Arduino, ESP32 with suitable module, Raspberry Pi with driver.

Difficulty

Intermediate

Time Required

1-2 weeks for wiring, basic code, platform integration and repeated test readings

Cost

RM4-RM18 module range in Malaysia; full project cost depends on scope.

Components

Relay Module, Arduino, ESP32 with suitable module, Raspberry Pi with driver

Overview

What is Relay Module?

A relay module lets a microcontroller switch a higher-voltage or higher-current load. It is common in smart home, irrigation, fan control and safety projects.

Engineering Reference

Quick Specs

Control InputDigital signal
Coil VoltageUsually 5V
ContactsCOM, NO, NC

Real Usage Notes

Suitable / Not Suitable

Suitable for

  • ✓ Pump control
  • ✓ Fan control
  • ✓ Smart light demos
  • ✓ Irrigation projects

Not suitable for

  • ✕ Fast PWM switching
  • ✕ Unsafe exposed AC wiring
  • ✕ Direct motor speed control

Build Planning

Difficulty

Relay Module is rated Intermediate. Plan around 1-2 weeks for wiring, basic code, platform integration and repeated test readingsdepending on wiring, libraries, calibration, dashboard/app integration and testing evidence.

Build Planning

Time Required

1-2 weeks for wiring, basic code, platform integration and repeated test readings

Malaysia Price Guidance

Cost

Typical module price range: RM4-RM18. This is component guidance only; a complete FYP cost depends on controller, sensors, casing, display, app/dashboard, documentation and timeline.

Connections

Pinout

VCC

Relay module supply.

GND

Common ground.

IN

Control input from microcontroller.

COM/NO/NC

Load-side switch terminals.

Platform Notes

Wiring Guides

Relay Module with Arduino

Use proper safety practices for AC loads. Keep low-voltage and high-voltage wiring separated.

VCC5V
GNDGND
INDigital pin such as D7

Fix Common Problems

Troubleshooting

Check wiring against the pinout before debugging code.
Use a stable power supply and common ground between modules.
Test the component with a simple example sketch before adding dashboard, app or database features.
Do not power motors, pumps or heavy loads directly from a microcontroller pin.

Troubleshooting

Common Mistakes

Confusing NO and NC terminals
No flyback/isolation consideration on cheap modules
Unsafe AC wiring during demos

FYP Ideas Using Relay Module

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Compare Options

Alternative Components

L298N

Use motor drivers for DC motor direction/speed instead of relays.

Student Questions

FAQ

Can ESP32 trigger a 5V relay?

Some relay modules trigger from 3.3V signals and some do not. Check the input circuit or use a transistor/driver.