What is Dimmer Switch : Working, Circuit Diagram, Interface with Arduino & Its Applications

Light in homes or businesses plays an essential role to create the correct mood & setting. So, the light’s intensity level will affect hugely our physical & emotional happiness in our home. Every room in the home requires different lights with different intensities. But controlling the lights or bulb intensity is not possible. So, a dimmer switch is equipped with the power to regulate the capacity of voltage for any lighting system. At present, there are different kinds of dimmer switches available in different sizes and shapes which are used based on the requirement. So this article discusses an overview of a dimmer switch – types with applications.


What is Dimmer Switch?

Dimmer switch definition is; a simple electronic device that is used to control the intensity range of lights is known as a dimmer switch like LED, CFL & Halogen. So this switch adjusts the light intensity by controlling the flow of current throughout the lamps. Generally, these switches are installed in homes in the dining or family rooms for controlling lighting so that energy can be conserved. The dimmer switch symbol is shown below.

Dimmer Switch Symbol
Dimmer Switch Symbol

How Does a Dimmer Switch Work?

The working principle of a dimmer switch is to control the amount of current flowing through a circuit thereby controlling the brightness. It controls the current by using a small motor to turn an internal resistance up and down quickly, between live and neutral wires. When there is more resistance in circuit, more voltage is required to pass through it and hence less current will flow through it (less voltage means more current). This method works similarly for AC circuits as well.

Types of Dimmer Switches

At present, dimmer switches are available in different types. Most dimmer switches utilize electronic low frequent bulbs, incandescent bulbs, magnetic low frequency, dimmable compact fluorescent light bulbs, etc.

Leading Edge Dimmers

These dimmer switches are frequently used for halogen and incandescent bulbs. These are cheaper and provide a higher wattage. These switches use TRIAC switch for power control.

Leading Edge Dimmer
Leading Edge Dimmer

LED-Ready Dimmers

LED-Ready dimmers are also known as trailing edge switches which are used for LED bulbs. These types of dimmers are very compatible with less wattage, so these are normally used to reduce the intensity of traditional light bulbs. As compared to the leading-edge light dimmer circuits, these are very better.

LED-Ready Dimmers
LED-Ready Dimmers

Single Pole Dimmers

These types of dimmer switches have a single switch to control the light intensity. By using these switches, light controlling can be done from a single location.

Single Pole Dimmer Switch
Single Pole Dimmer Switch

3-Way or 4 -Way Dimmers

These dimmers normally do not have ON & OFF markings however used for controlling the light from multiple locations. So these are well-matched with different types of loads.

3 Way or 4 Way
3 Way or 4 Way

Multi-Location Dimmers

These dimmers are used for controlling the light intensity from more than one location. Based on the arrangement, any device can control the dimming on the light dimmer circuit.

Multi Location Dimmer Switch
Multi-Location Dimmer Switch

Plug-In Dimmers

These types of dimmers are ideal for controlling the floor & table lamps intensity. The designing of these can be done to access easily in the dark too. But all you have to do is connect it in between the wall socket & light fixture, put the controller in an accessible location & utilize it when required.

Plug-In Dimmers
Plug-In Dimmers

Rotary Dimmers

The most common type of dimmer switch is known as a rotary dimmer, which uses an electric motor to adjust the position of a set of long metal blades inside a bulb. When the blades are positioned parallel with each other, they block all light from passing through. As they are rotated into a perpendicular position, more and more light passes through until all blades are aligned and it becomes fully bright again.

This type of dimmer is often found in theaters or concert halls where it is necessary to change lighting levels quickly or gradually during shows or performances by using  a knob.

Rotary Dimmer Switch
Rotary Dimmer Switch

Touch Screen Dimmer Switches

These dimmer switches are frequently arranged on a wall within the home. These switches are very easy to utilize and it gives a fashionable look to the home. These switches are essential parts of a home automation system.

Touch Screen Dimmer
Touch Screen Dimmer

Toggle Dimmers

As the name suggests these types of dimmer switches toggle or shift like a typical light switch. But the light level routinely comes back to its earlier settings.

Toggle Dimmers
Toggle Dimmers

Slide Dimmers

Slide dimmer switches simply allow you to control the brightness of the light by sliding a switch up and down. Some slide dimmers can also be available with a button that slides the device automatically from back & forth to dim lights.

Slide Dimmers
Slide Dimmers

Rocker Dimmers

Rocker dimmers include a slide that controls the dim level of light until it achieves the preferred light level. These are suitable for home lighting solutions and also for those who desire to maintain the lights most of the time at a particular level.

Rocker Dimmers
Rocker Dimmers

Tap Dimmers

Tap dimmer switches are suitable for smart homes because they are cost-efficient & compact. This is one of the types of smart switches which mainly include a simple button or touchpad that allows the user to set their light level.

Tap Dimmers
Tap Dimmers

Smart Dimmers

These dimmer switches allow you to control your lights with your smartphone otherwise other smart devices. Some smart dimmers offer other features like programmable timers.

Smart Dimmers
Smart Dimmers

Dimmer Switch Circuit Diagram

The circuit diagram of a touch dimmer switch using an Arduino is shown below. In this project, the dimmer action is simply attained by using a Touch Sensor. A dimmer switch is used to control the intensity of the light otherwise the light will glow at high brightness so that it consumes more power.
The required components to build this project mainly include Arduino UNO, touch sensor, small bulb, 2N2222 NPN transistor, power supply, breadboard, and connecting wires.

Touch Dimmer Switch using an Arduino
Touch Dimmer Switch using an Arduino

The essential components used in this project are Arduino UNO and a touch sensor. The main function of Arduino Uno in this project is to detect the o/p from the touch sensor & drive the bulb correspondingly. A Touch Sensor like TTP223 Touch Pad Detector IC is an input device, used to detect proximity or physical touch.

The connections of this circuit are made as per the above diagram. The touch sensor includes three pins SIG, GND, and VCC. Here, the power supply is given by connecting VCC to 5V, the GND pin to GND, and the SIG pin is connected to the digital I/O pin (Pin-8) of the Arduino UNO board. A small incandescent bulb is connected to Arduino by using a transistor and this transistor is connected to any digital input/output pin of Arduino Uno with a current limiting resistor.

After that, connect the transistor’s collector terminal to the 5V power supply & lastly, connect a bulb in between the emitter (E) & GND terminals. That’s how an Interface of a Dimmer Switch with Arduino is done.

Working

The working of this project is, that whenever the touch sensor is not touched then the sensor’s SIG pin will stay LOW. Similarly, when we touch the touch sensor, the SIG pin of this sensor will goes HIGH. So we can observe this change from LOW to HIGH when it is connected to Arduino.

As a result, once the touch sensor is touched then Arduino UNO notices the change within the logic condition of the output of this sensor & controls the bulb with PWM. Therefore, this bulb is simply connected to a PWM pin of UNO. When we touch the sensor continuously then Arduino UNO gradually enhances the bulb intensity using PWM.

So this process will continue until the maximum intensity of the bulb is attained. To reduce the intensity of the bulb, you need to double-tap the touch sensor. Arduino UNO programmed is done in such a way that, if a double-tap is done then it has to decrease the intensity of the bulb & therefore works as a dimmer switch.

Code

int led = 3;
int sen=8;
int val=0;
void setup()
{
pinMode(sen,INPUT);
pinMode(led,OUTPUT);
digitalWrite(sen,LOW);
digitalWrite(led,LOW);
}
void loop()
{
while(digitalRead(sen)==LOW);
while(digitalRead(sen)==HIGH);
{
if(val<=255)
{
analogWrite(led,val);
val++;
delay(15);
}
}

delay(1000);
while(digitalRead(sen)==HIGH)
{
if(val>=0)
{
analogWrite(led,val);
val–;
delay(15);
}
}
}
The above simple touch dimmer switch circuit is implemented by using an Arduino UNO & a touch sensor. So this project is used to control the intensity of a bulb by just touching the sensor.

Pros and Cons of Dimmer Switch

The pros of the dimmer switch include the following.

  • Using these switches, we can conserve 25% of energy by controlling the light intensity. When the energy is used less then the electricity cost will be less.
  • Dimmer switches are ideal for homes, schools, and colleges.
  • These are very easy to install but you simply need an electrician to connect.
  • The light adjustment can be done according to your requirements by using these switches.
  • These switches are available with a feature that remembers your regular settings once you utilize them again.
  • These are very convenient to operate.
  • From multiple locations, you can control home lighting from different locations of the house.
  • These switches can expand the light bulb’s life.
  • Dimmer switches give a better look and a classy feel to your home & they can be simply adjusted depending on the décor, wallpaper, or painting of the room.

The cons of the dimmer switches include the following.

  • These switches are not compatible with each light within a home.
  • Its installation can be done only by an electrician.

Applications

The applications of the dimmer switch include the following.

  • The dimmer switch is used to control the light intensity from high to low and low to high.
  • These switches can be installed in different locations in the home like the kitchen, bathroom, bedroom, living room, etc.
  • Dimmer switches are appropriate to use with halogen & incandescent lamps. However, some fluorescent lamps & LEDs with special ballasts can also be controlled by using this switch.
  • These are frequently used in homes & businesses to save energy & also to control the environment of lighting.
  • Dimmer switches are very helpful in extending the lifetime of your LED lights & electric bulbs.

Thus, this is all about brief information on dimmer switches like working, types, advantages, disadvantages, and their applications. there are several reasons to use dimmer switches in your house and business which are discussed above. Whenever the bulbs or lights aren’t working at full capacity, then they utilize less energy & conserve the life of the lights. So dimming switches can create a room more comfortable & a lovely ambiance for an event, gathering, or party. These switches are energy efficient, the lighting system can be controlled easily, efficient mood lighting provides long life to your lighting & its installation is easy. There are different factors that need to consider while selecting a dimmer switch like the type of dimmer, lighting source, and control style. Here is a question for you, what is an alternate name for a dimmer switch?

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