How to Start with a UNO R3 Board for Arduino Projects
Start with a UNO R3 compatible board when you learn Arduino for the first time. It carries an ATmega328P chip, runs at 16MHz, and gives 14 digital I/O pins and 6 analog inputs. The board costs from $9.27, with USB-B or Type-C versions. An OLED display and a DHT22 sensor make a complete first project.
Quick facts
| Fact | Value |
|---|---|
| Chip | ATmega328P, 16MHz |
| USB-serial | CH340G |
| Digital I/O | 14 pins |
| Analog inputs | 6 pins |
| Board price | From $9.27, with cable $10.38 to $10.64 |
| First sensors | OLED $5.47, DHT22 $5.96 |
What is on a UNO R3 compatible board?
The board carries an ATmega328P chip with a CH340G USB-serial chip. It runs at 16MHz and works with the Arduino IDE.
It gives 14 digital I/O pins and 6 analog inputs. That is enough pins for a display, a sensor, and a few buttons at once.
Arduino documents the Uno Rev3 layout and pin map. The compatible board follows that same layout.
Should you pick USB-B or Type-C?
The board-only Type-C version costs $9.27. The board-only USB-B version costs $9.38.
With a cable included, the Type-C version costs $10.38 and the USB-B version costs $10.64. Pick the port that matches your cables.
Both versions give the same ATmega328P chip and pin count. The USB port is the only difference.
How do you add an OLED display?
The 0.96 inch OLED display measures 128 by 64 pixels on I2C. It uses 4 pins, GND, VCC, SCL, and SDA, and takes 3.3V to 5V.
That voltage range suits the UNO board with no extra level shifting. The display costs from $5.47 by color.
Show sensor readings on the display while you test. Update it once per loop so the numbers stay readable.
How do you read temperature and humidity?
The DHT22 sensor reads 0 to 100% relative humidity and -40 to 80C. It runs on 3.3V to 5.5V with a single-bus output.
That range suits indoor and outdoor bench tests. The sensor costs $5.96 and works with Arduino and ESP32 boards.
Wire its data pin to a digital pin on the UNO board. Read it once per 2 sec, since the sensor needs time between reads.
What switches and buttons do you need?
The tactile switch kit holds 180 momentary switches in 10 values. It covers 6x6mm sizes from 4.3mm to 13mm, plus 7x7x14mm.
The kit costs $11.31 with an organizer box. That keeps each switch value in its own slot.
Wire one switch between a digital pin and ground for a first input test. Use the built-in pull-up resistor in the sketch.
How does the UNO compare with the ESP32 DevKit V1?
The DevKit V1 is a 30-pin WROOM-32 board with WiFi and Bluetooth. Its board versions cost $15.99 to $17.99.
The UNO gives 14 digital pins and no WiFi. It suits wired sensor and display projects with no radio need.
Pick the UNO to learn Arduino basics. Pick the DevKit V1 when the project needs WiFi or Bluetooth.
How the options compare
| Part | Key spec | Price |
|---|---|---|
| UNO R3, Type-C board only | ATmega328P, 16MHz, 14 digital pins | $9.27 |
| UNO R3, USB-B board only | ATmega328P, 16MHz, 14 digital pins | $9.38 |
| UNO R3, Type-C with cable | ATmega328P, 16MHz, 14 digital pins | $10.38 |
| UNO R3, USB-B with cable | ATmega328P, 16MHz, 14 digital pins | $10.64 |
| OLED display | 0.96 inch, 128 by 64 pixels, I2C | From $5.47 |
| DHT22 sensor | 0 to 100% RH, -40 to 80C | $5.96 |
| Tactile switch kit | 180 switches, 10 values | $11.31 |
How do you build your first UNO project?
- Connect the board to your computer over USB.
- Pick the Arduino Uno board in the Arduino IDE.
- Load a blink sketch to confirm the board and USB link.
- Wire the OLED display to the I2C pins, GND, VCC, SCL, and SDA.
- Wire the DHT22 data pin to a digital pin.
- Load the sketch and check that the display shows temperature and humidity.
Parts that fit this guide
In-stock parts ship from the New York, USA warehouse in 1-2 business days. Prices below are the live store prices we verified on November 10, 2026.
UNO R3 Compatible Development Board, ATmega328P CH340G – USB / Type-C ($9.27)
UNO R3 compatible board at $9.27 to $10.64 by version. It carries an ATmega328P chip, runs at 16MHz, and gives 14 digital pins and 6 analog inputs.
0.96 Inch OLED Display Module, SSD1306, I2C, 128×64, for Arduino / ESP32 / ESP8266 ($5.47)
OLED display at $5.47. It measures 0.96 inch with 128 by 64 pixels on I2C, and takes 3.3V to 5V.
DHT22 / AM2302 Digital Temperature & Humidity Sensor Module ($5.96)
DHT22 sensor at $5.96. It reads 0 to 100% relative humidity and -40 to 80C on 3.3V to 5.5V.
Tactile Pushbutton Switch Kit, 6x6mm, 10 Values, 180-Piece with Organizer Box ($11.31)
Tactile switch kit at $11.31. It holds 180 momentary switches in 10 values with an organizer box.
ESP32 DevKit V1 Development Board, 30-Pin WROOM-32, WiFi + Bluetooth ($11.99)
ESP32 DevKit V1 at $11.99 listed, with board versions at $15.99 to $17.99. It is a 30-pin WROOM-32 board with WiFi and Bluetooth.
Shop the full range: Arduino-Compatible Boards at Quality RC Parts. See also: Related guide.
Frequently asked questions
What chip does the UNO R3 compatible board use?
An ATmega328P chip with a CH340G USB-serial chip, running at 16MHz.
How many pins does the board have?
It gives 14 digital I/O pins and 6 analog inputs.
Should I pick USB-B or Type-C?
Pick the port that matches your cables. Board-only prices are $9.27 for Type-C and $9.38 for USB-B.
Does the board work with the Arduino IDE?
Yes. It works with the Arduino IDE, and Arduino documents the Uno Rev3 layout.
Sources
Last updated: November 10, 2026.