SENSORS/ACTUATORS

INTERNET OF THING (IoT)

ESP32 - DIP Switch

DIP (Dual In-line Package) switches are commonly used in electronics for configuration purposes, such as setting device addresses, enabling or disabling features, etc. In this tutorial, we are going to learn how to use the DIP switch with ESP32. In detail, we will learn:

What is DIP switch and how it works
How to connect the DIP switch to ESP32
How to program ESP32 to read the ON/OFF state of DIP switch
How to program ESP32 to read the integer number set by DIP switch

DIP (Dual In-line Package) switches are frequently employed in electronics for configuration purposes, such as setting device addresses, activating or deactivating features, and more. In this tutorial, we'll explore the utilization of the DIP switch with ESP32. Specifically, we'll cover the following topics:

Understanding what a DIP switch is and its working principles.
Connecting the DIP switch to the ESP32.
Programming the ESP32 to detect the ON/OFF state of the DIP switch.
Programming the ESP32 to interpret the integer value set by the DIP switch.

Hardware Used In This Tutorial

1	×	ESP-WROOM-32 Dev Module
1	×	USB Cable Type-C
1	×	DIP Switch
1	×	Breadboard
1	×	Jumper Wires
1	×	(Recommended) ESP32 Screw Terminal Adapter

Or you can buy the following sensor kits:

1	×	DIYables Sensor Kit (30 sensors/displays)
1	×	DIYables Sensor Kit (18 sensors/displays)

Disclosure: some of these links are affiliate links. We may earn a commission on your purchase at no extra cost to you. We appreciate it.

Introduction to DIP Switch

DIP switches serve as a fundamental components for device configuration, enabling users to adjust parameters like device addresses, communication settings, security codes, operation modes, and system preferences across various industries and applications.

A DIP switch comprises multiple small slide switches grouped together, with each switch referred to as a "position". DIP switches come in various types determined by the number of positions they offer. Options include 2-position, 4-position, 5-position, 6-position, 8-position, and 10-position DIP switches...

Each position on a DIP switch corresponds to a bit of a configurable number. By toggling the positions between ON and OFF, users can set the desired numeric value. This flexibility allows for precise configuration of parameters according to specific requirements.

Pinout

image source: diyables.io

A DIP switch is composed of dual rows of pins, with the number of pins in each row matching the available switch positions. For instance, a 4-position DIP switch contains a total of 8 pins, evenly distributed with 4 pins on each side. Within the DIP switch structure, every pair of opposing pins forms a slide switch. It's important to note that distinguishing between pins on the two sides isn't required as they are interchangeable.

How It Works

In DIP switches, when a switch is in the ON position, it indicates that the switch is closed, establishing an electrical connection that allows current to flow through it.

Conversely, when a switch is in the OFF position, it means that the switch is open. In this state, the electrical connection is interrupted, preventing current from flowing through the switch.

To clarify:

ON position: Forms a closed circuit, enabling current flow.
OFF position: Results in an open circuit, blocking current flow.

When connecting one side of the switch to GND and the other to an ESP32 pin, and configuring the ESP32 pin as a pull-up digital input, the following table illustrates the relationship between the switch position and the values read from the ESP32:

DIP switch position	Binary representation	Circuit state	ESP32 pin state
ON	1	CLOSED	LOW
OFF	0	OPEN	HIGH

In the next parts, we will use 4-position DIP switch for example. You can easily to adapt for 2-position DIP switches, 3-position DIP switches, 5-position DIP switches, 6-position DIP switches, 8-position DIP switches, and 10-position DIP switches...

Wiring Diagram

This image is created using Fritzing. Click to enlarge image

If you're unfamiliar with how to supply power to the ESP32 and other components, you can find guidance in the following tutorial: How to Power ESP32.

ESP32 Code - DIP Switch

We will learn through two pieces of code:

Reading the ON/OFF state of individual position on the DIP switch.
Encoding the positions into a number.

ESP32 code - Reading the ON/OFF state of the DIP switch

/* * This ESP32 code is created by esp32io.com * * This ESP32 code is released in the public domain * * For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-dip-switch */ #define POSITION_NUM 4 #define ON LOW #define OFF HIGH // define the pins connected to the dip switch const int SWITCH_PINS[] = { 26, 27, 14, 12 }; void setup() { // initialize serial communication Serial.begin(9600); // set the dip switch pins as inputs with pull-up resistors enabled for (int i = 0; i < POSITION_NUM; i++) pinMode(SWITCH_PINS[i], INPUT_PULLUP); } void loop() { // Read the state of each switch position for (int i = 0; i < POSITION_NUM; i++) { Serial.print("position "); Serial.print(i + 1); Serial.print(": "); int state = digitalRead(SWITCH_PINS[i]); if (state == ON) Serial.println("ON "); else Serial.println("OFF "); } Serial.println(); // add a delay to prevent rapid readings delay(500); }

Quick Instructions

If this is the first time you use ESP32, see how to setup environment for ESP32 on Arduino IDE.
Do the wiring as above image.
Connect the ESP32 board to your PC via a micro USB cable
Open Arduino IDE on your PC.
Select the right ESP32 board (e.g. ESP32 Dev Module) and COM port.
Do wiring as above wiring diagram
Connect ESP32 to PC via USB cable
Open Arduino IDE
Select the right board and port
Click Upload button on Arduino IDE to upload code to ESP32
Switch each position on the DIP Switch to ON one by one.
See the result on Serial Monitor.

COM6

Send

position 1: OFF position 2: OFF position 3: OFF position 4: OFF position 1: ON position 2: OFF position 3: OFF position 4: OFF position 1: ON position 2: ON position 3: OFF position 4: OFF position 1: ON position 2: ON position 3: ON position 4: OFF position 1: ON position 2: ON position 3: ON position 4: ON

Autoscroll Show timestamp

Clear output

9600 baud

Newline

ESP32 code - Encoding the states of DIP switch into a number

/* * This ESP32 code is created by esp32io.com * * This ESP32 code is released in the public domain * * For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-dip-switch */ #define POSITION_NUM 4 #define ON LOW #define OFF HIGH // define the pins connected to the dip switch const int SWITCH_PINS[] = { 26, 27, 14, 12 }; void setup() { // Initialize serial communication Serial.begin(9600); // Set the DIP switch pins as inputs with pull-up resistors enabled for (int i = 0; i < POSITION_NUM; i++) pinMode(SWITCH_PINS[i], INPUT_PULLUP); } void loop() { int encoded_state = 0; for (int i = 0; i < POSITION_NUM; i++) { int state = digitalRead(SWITCH_PINS[i]); if (state == ON) encoded_state |= 1 << (POSITION_NUM - i - 1); } Serial.print("encoded state: "); Serial.println(encoded_state); // add a delay to prevent rapid readings delay(500); }

Quick Instructions

If this is the first time you use ESP32, see how to setup environment for ESP32 on Arduino IDE.
Do the wiring as above image.
Connect the ESP32 board to your PC via a micro USB cable
Open Arduino IDE on your PC.
Select the right ESP32 board (e.g. ESP32 Dev Module) and COM port.
Upload the above code to ESP32
Switch each position on the DIP switch to ON one by one.
See the result on Serial Monitor, it look like below.

COM6

Send

encoded state: 0 encoded state: 1 encoded state: 2 encoded state: 3 encoded state: 4 encoded state: 5 encoded state: 6 encoded state: 7 encoded state: 8 encoded state: 9 encoded state: 10 encoded state: 11 encoded state: 12 encoded state: 13 encoded state: 14 encoded state: 15

Autoscroll Show timestamp

Clear output

9600 baud

Newline

Please note that the value depends on positions of each slide switches. The below table shows the mapping between ON/OFF position and the integer value for 4-position DIP switch:

Position-1	Position-2	Position-3	Position-4	Binary Value	Decimal Value
OFF	OFF	OFF	OFF	0000	0
OFF	OFF	OFF	ON	0001	1
OFF	OFF	ON	OFF	0010	2
OFF	OFF	ON	ON	0011	3
OFF	ON	OFF	OFF	0100	4
OFF	ON	OFF	ON	0101	5
OFF	ON	ON	OFF	0110	6
OFF	ON	ON	ON	0111	7
ON	OFF	OFF	OFF	1000	8
ON	OFF	OFF	ON	1001	9
ON	OFF	ON	OFF	1010	10
ON	OFF	ON	ON	1011	11
ON	ON	OFF	OFF	1100	12
ON	ON	OFF	ON	1101	13
ON	ON	ON	OFF	1110	14
ON	ON	ON	ON	1111	15

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