SENSORS/ACTUATORS

INTERNET OF THING (IoT)

ESP32 S3 UNO - DIP Switch

This ESP32 S3 Uno DIP switch tutorial shows you how to wire a DIP switch to the ESP32 S3 Uno form board and read it with Arduino code. DIP switches are small banks of slide switches. Makers use them to set a device address, pick a mode, or turn features on and off without changing the code. You will see the state of each switch, and the number they make together, in the Serial Monitor.

In this tutorial, you will:

Learn what a DIP switch is and how its pins work
Wire a 4-position DIP switch to the ESP32 S3 Uno
Read the ON/OFF state of each switch with digitalRead() and INPUT_PULLUP
Turn the switch positions into a binary number and a decimal value
Adapt the code for 2, 6, 8 or 10-position DIP switches

Hardware Preparation

1	×	ESP32 S3 Uno-form Board
1	×	USB Cable Type-A to Type-C (for USB-A PC)
1	×	USB Cable Type-C to Type-C (for USB-C PC)
1	×	DIP Switch
1	×	Breadboard
1	×	Jumper Wires

Or you can buy the following kits:

DIYables Sensor Kit (18 sensors/displays)

Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you.
Additionally, some of these links are for products from our own brand, DIYables .

Overview of DIP Switch

A DIP switch is a simple way to give your project settings that stay in place, even after power is off. Knowing how it is built helps you wire it right the first time.

The name DIP means Dual In-line Package. One DIP switch holds several tiny slide switches in one small body. Each slide switch is called a "position". You can buy them with 2, 4, 5, 6, 8 or 10 positions.

Devices use DIP switches to set things like a device address, communication options, a security code, an operating mode or system preferences. Because each position is ON or OFF, every position works like one bit of a number. By sliding the switches, you choose the number you want.

Pinout

image source: diyables.io

A DIP switch has two rows of pins. Each row has one pin per position, so a 4-position DIP switch has 8 pins, 4 on each side. The two pins that face each other belong to the same slide switch. The sides are interchangeable, so it does not matter which row you connect to the board and which row you connect to GND.

How It Works

Each position is just a simple on/off contact. Once you know what ON and OFF mean in the circuit, the code becomes easy to follow.

ON position

The switch is closed. Current can flow from one pin to the other.

OFF position

The switch is open. The connection is broken and no current can flow.

Reading it with the ESP32 S3 Uno

In this project, one side of each switch goes to GND and the other side goes to an ESP32 S3 Uno pin set as a pull-up input. The internal pull-up resistor keeps the pin HIGH when the switch is open. When you slide the switch ON, the pin is pulled to GND and reads LOW. The table below sums it up.

DIP switch position	Binary representation	Circuit state	ESP32 S3 Uno pin state
ON	1	CLOSED	LOW
OFF	0	OPEN	HIGH

The examples below use a 4-position DIP switch. You can easily change them for 2, 3, 5, 6, 8 or 10-position DIP switches.

ESP32 S3 Uno Pinout

The image below shows the pinout of the ESP32 S3 Uno form board. Use it to find the Uno header pins (D2, D3, D4, D5…) and their GPIO numbers when you wire the DIP switch.

Wiring Diagram

Connect one row of the DIP switch to four digital pins, and the other row to GND. No external resistors are needed, because the code turns on the internal pull-up resistors.

This image is created using Fritzing. Click to enlarge image

DIP Switch Pin	ESP32 S3 Uno Pin
Position 1 (one side)	D2 (GPIO18)
Position 2 (one side)	D3 (GPIO17)
Position 3 (one side)	D4 (GPIO19)
Position 4 (one side)	D5 (GPIO20)
All pins on the other side	GND

ESP32 S3 Uno Code - DIP Switch

There are two sketches below. The first one tells you whether each switch is ON or OFF. The second one combines all positions into a single number, which is how DIP switches are used in real devices.

ESP32 S3 Uno code - Reading the ON/OFF state of the DIP switch

This sketch sets the four pins as INPUT_PULLUP inputs. Every half second, it reads each pin and prints "ON" when the pin is LOW and "OFF" when it is HIGH. Note that the code uses GPIO numbers (18, 17, 19, 20), not the Uno labels D2 to D5.

/* * This ESP32 S3 Uno code was developed by newbiely.com * * This ESP32 S3 Uno code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/esp32-s3-uno/esp32-s3-uno-dip-switch */ #define POSITION_NUM 4 #define ON LOW #define OFF HIGH // define the ESP32 S3 Uno pins connected to the dip switch (D2, D3, D4, D5) const int SWITCH_PINS[] = { 18, 17, 19, 20 }; 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); }

Detailed Instructions

New to the ESP32 S3 Uno? Follow ESP32 S3 Uno - Getting Started first.
Wire it up as shown in the diagram.
Connect the board to your computer with a USB Type-C cable.
Open Arduino IDE, choose the ESP32S3 Dev Module board and the correct COM port.
Copy the code above and paste it into Arduino IDE.
Upload the code by clicking the Upload button.
Open the Serial Monitor and set the baud rate to 9600.
Slide the switches ON one at a time and watch the output change.
Tip: If every position shows OFF, check that the other side of the DIP switch is really connected to GND.

Newbiely | Arduino IDE 2.3.8

──

☐

Newbiely.ino

···

8 Serial.println("Hello World!");

Output

Serial Monitor

Message (Enter to send message to 'ESP32S3 Dev Module' on 'COM15')

New Line

9600 baud

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

Ln 11, Col 1

ESP32S3 Dev Module on COM15

ESP32 S3 Uno code - Encoding the states of DIP switch into a number

This sketch treats each position as one bit. Position 1 is the highest bit and position 4 is the lowest bit. When a switch is ON, the code sets its bit with a shift and an OR, then prints the final value as a decimal number.

/* * This ESP32 S3 Uno code was developed by newbiely.com * * This ESP32 S3 Uno code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/esp32-s3-uno/esp32-s3-uno-dip-switch */ #define POSITION_NUM 4 #define ON LOW #define OFF HIGH // define the ESP32 S3 Uno pins connected to the dip switch (D2, D3, D4, D5) const int SWITCH_PINS[] = { 18, 17, 19, 20 }; 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); }

Detailed Instructions

New to the ESP32 S3 Uno? Follow ESP32 S3 Uno - Getting Started first.
Wire it up as shown in the diagram.
Connect the board to your computer with a USB Type-C cable.
Open Arduino IDE, choose the ESP32S3 Dev Module board and the correct COM port.
Copy the code above and upload it to the ESP32 S3 Uno.
Open the Serial Monitor at 9600 baud.
Slide the switches into different positions and watch the number change.
Tip: Want more positions? Change POSITION_NUM and add more GPIO numbers to SWITCH_PINS[].

Newbiely | Arduino IDE 2.3.8

──

☐

Newbiely.ino

···

8 Serial.println("Hello World!");

Output

Serial Monitor

Message (Enter to send message to 'ESP32S3 Dev Module' on 'COM15')

New Line

9600 baud

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

Ln 11, Col 1

ESP32S3 Dev Module on COM15

The number depends on which slide switches are ON. The table below shows every combination for a 4-position DIP switch and the value the ESP32 S3 Uno prints.

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

Video Tutorial

Watch the video below to see this ESP32 S3 Uno project step by step.

FAQ

Do I need resistors to connect a DIP switch to the ESP32 S3 Uno?

No. The code uses INPUT_PULLUP, which turns on the internal pull-up resistor of each pin. The pin reads HIGH when the switch is OFF and LOW when it is ON. Just connect the other side of the DIP switch to GND.

Why does the code use 18, 17, 19 and 20 instead of 2, 3, 4 and 5?

On the ESP32 S3 Uno, the header labels are not the same as the GPIO numbers. D2 is GPIO18, D3 is GPIO17, D4 is GPIO19 and D5 is GPIO20. The code must use the GPIO numbers. If you write 2, 3, 4 and 5, the board reads different pins and the switches seem to do nothing.

Can I connect the DIP switch to 5V instead of GND?

No. ESP32 S3 Uno pins work at 3.3V and are not 5V tolerant. With the wiring in this tutorial, the switches only connect pins to GND, so no voltage ever goes into the board. This is the safest way to use a DIP switch.

Why is ON read as LOW?

With a pull-up input, the pin stays HIGH until something pulls it to GND. Sliding a switch ON connects the pin to GND, so it reads LOW. That is why the code defines ON as LOW and OFF as HIGH.

How do I use an 8-position DIP switch?

Set POSITION_NUM to 8 and add four more GPIO numbers to SWITCH_PINS[], for example D7 (GPIO14), D8 (GPIO21), D10 (GPIO10) and D11 (GPIO11). The encoded value will then go from 0 to 255. Avoid D0/D1, and avoid D6 and D9 because they are boot strapping pins.

What if my project needs more pins than the Uno headers give?

The ESP32 S3 Uno has two extra rows of holes with more GPIOs: GPIO15 and GPIO16 (I/O, PWM, analog), GPIO45 and GPIO35 to GPIO42 (I/O, PWM), and GPIO47/GPIO48 (output only, PWM). Solder pin headers to use them and write the GPIO number in code. For a large DIP switch, GPIO35 to GPIO42 and GPIO15/GPIO16 are good inputs. Do not use GPIO47/GPIO48, because they are output only. Be careful: GPIO47 and GPIO48 may run at 1.8V instead of 3.3V on some modules (especially ones with "V" in the name, like R8V or R16V), so 3.3V devices can be damaged or act strangely. Also, GPIO0, GPIO3 (D6), GPIO45 and GPIO46 (D9) are boot strapping pins, and a wrong connection can stop the board from booting or uploading code. Use the other extra pins first.

Troubleshooting

Problem	Possible Cause	Solution
No COM port in Arduino IDE	USB driver missing or board not in upload mode	Install the CP210x or CH340 driver, or hold BOOT while pressing RESET, then upload again
All positions always show OFF	Other side of the DIP switch is not connected to GND	Connect every pin on the other row to a GND pin and check the breadboard rows
One position never changes	Wire on the wrong pin or loose jumper	Check that positions 1 to 4 go to D2, D3, D4 and D5
Switches seem to do nothing	Code uses Uno numbers 2, 3, 4, 5 instead of GPIO numbers	Use 18, 17, 19 and 20 in SWITCH_PINS
Values jump randomly	Pins set as INPUT without pull-up	Keep pinMode set to INPUT_PULLUP
Encoded number is reversed	Bit order differs from what you expect	Position 1 is the highest bit, so swap the order of SWITCH_PINS if you need the other way
Serial Monitor shows strange characters	Wrong baud rate	Set the Serial Monitor to 9600 baud

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