Skip to content

Which is the best to use between Arduino Leonardo and Arduino UNO

PCBs are the best to make your designs fit your exact needs. We can use pins for anything from small prototyping to complex electronics. So, which do you think is the best to use between Arduino Leonardo and UNO?

Well, it depends on what you’re going to use your board for. The Arduino UNO is a little bit more beginner-friendly. It is excellent for those who have not used the Arduino before. Those who want to try out a new coding language such as C++ also like it.

Arduino Leonardo overview

It is a unique microcontroller board that centers on ARM architecture and made by Arduino. It has many features such as a DHT sensor, Ethernet, USB-UART bridge, VGA, audio, and many more.

This microcontroller board, the Arduino Leonardo, is based on ATmega32u4 design. The ATmega32u4 is a microcontroller board with 32 KB 2.5KB RAM flash memory. It operates at 16MHz with a USB 2.0 interface. This Arduino board has 14 digital I/O pins and six analog inputs. We can program the Arduino Leonardo can using the in-built C++ programming language. Also, the Arduino Leonardo has a DIP socket when we remove the ATmega32u4 from the board.

Arduino Leonardo advantages

Arduino UNO

The Arduino Leonardo has many advantages. It is excellent for those who want to learn about 3D printers. It uses an Arduino board for its controller. Manufacturers test it to work well with 3D printers and video game consoles. They include the Playstation 4 and Xbox One. We can also use this Arduino board for DIY projects and change it according to your needs.

We can use the Arduino Leonardo for many projects, and the ATmega32u4 can make it possible. One can program this Arduino board without removing the ATmega32u4 from its socket. Beginners find it helpful. Furthermore, it can run on different operating systems. Depending on your computer system, they include Windows, Linux, and Mac OSX.

This Arduino board can also do web programming. Therefore, it makes it great for web-centric projects. Furthermore, the Arduino Leonardo can work well with 3D printers and gaming consoles. Also, you can program this board via C++, which makes it easier for beginners.

Arduino Leonardo disadvantages

The Arduino Leonardo has a few disadvantages, though, too. The Arduino board is not suitable for those who want to do complex projects. There are very few pins available on its PCB. It is not good to use this Arduino board for any project. Especially those that need precise time control. Its operating frequency is much lower than the usual ones.

The Arduino Leonardo can also do small projects. But you must be careful while using it, especially when soldering. You must take your time and ensure that you connect before powering it up. They include the ATmega32u4 and other components. Mis-soldering even one connection can make your Arduino Leonardo useless.

Arduino Leonardo Features

The Arduino Leonardo has a few exciting features, making it great for beginners. The first thing worth mentioning is the 32U4 chip present on the board. This ATmega32u4 microcontroller board has a USB-UART bridge along with a DMA controller. The DMA controller transfers data from one place to another. It does not go through the Microcontroller (MCU). Besides, the ATmega32u4 has a good amount of memory. Therefore, it helps in the smooth functioning of your Arduino Leonardo projects.

The input voltage range of the Arduino Leonardo is 3.3V to 5.5V. We can program the voltage using the DIP reset switch present on the board. Also, the Arduino has a few other exciting features. They include 16 digital output pins and six analog input pins.

Arduino Leonardo operating system

The operating system used on the Arduino Leonardo is Linux. We optimize it for low power consumption. Rayming PCB & Assembly test it to work well with many devices. They include 3D printers, video game consoles, drones, robots, and many more. The Arduino Leonardo can operate at 16MHz and even lower to save power.

Arduino Leonardo pinouts

The Arduino Leonardo has 14 digital I/O pins, six analog inputs, and a DIP socket. This DIP socket helps program the Arduino board. You can do this by removing its ATmega32u4 from the circuit when needed.

Voltage Regulator

The Arduino Leonardo has a voltage regulator, which regulates the output of 3.3V. You can power this board with a power supply or USB connection to the computer. If you use batteries to power this Arduino board, make sure that the voltage does not exceed 7-9V.

The Arduino Leonardo also has a voltage regulator. It converts the 9V into 5V for the smooth functioning of your Arduino project.

The USB jack, Power Jack, and Reset button are the essential components. We use them for resetting your Arduino Leonardo.

The DIP socket is the component used to program and repair such an Arduino board. So, you have to make sure that you have removed the ATmega32u4 from its socket. You need to do it before starting any programming process.

The LED, Power indicator, USB jack, Reset button, and Power Jack are suitable components. They take care of your wonderful Arduino board as they help when repairing or programming your board.

Arduino Leonardo Applications

The Arduino Leonardo has several applications. It is excellent for those who want to make drones, robots, drones, and other equipment. The Arduino works with almost any device, and we can use it in various ways.

The Arduino Leonardo is the best board among all others available. You will not find any other better board than this one for the price you will pay for it.

Industrial Automation:

It uses industrial control systems and information technology. They assist in running factories and other industrial facilities. Industrial Automation is commonly helpful for development or progress in various industries. Automation systems have been around since the 1900s. They were initially helpful in improving industrial productivity. These days, we use industrial automation to describe computerized systems. They control the processes found within an industrial facility.

Health and Security Systems:

These systems are among the most common automation systems used today. Health and security systems are crucial in ensuring that we all stay safe and healthy. It starts from pumping water to delivering the right medicine dosage.

Computerized control systems can monitor conditions within a facility. They also identify trends and predict future events. Also, most industrial automation systems can automatically modify their behavior. However, they depend on various factors, both internal and external.

Creating a wireless keyboard:

You can use it to create a wireless computer keyboard. It is quite easy to create one if you follow the right rules and guidelines. If you have any doubts about the same, you can check our blog on making a wireless computer keyboard.

Automatic Pill Dispenser:

It is a highly automated pill dispenser system that can dispense pills automatically. We can use it in hospitals, nursing homes, residences, and other places to take their medicines.

Embedded Systems:

Embedded systems are computer systems meant for a particular purpose. Hence, we embed them into a machine or other device, and they do their job as per the requirements. In simple terms, an embedded system is anything you put in your TV, and it doesn’t get turned on by itself.

A basic example of an embedded system is a thermostat in your house. This thermostat will turn on when the temperature outside is cold enough. It is ideal for your house to use the air-conditioner to cool down the house.

USB Trackpad:

USB Trackpad is a device that you can plug into your computer to control the mouse pointer on your screen. It allows you to move, rotate and zoom the object on the screen with your mouse. For a USB trackpad to work, you must use a driver. The driver will feed information from the USB Trackpad on your computer back to it.

The General Overview of Arduino UNO

arduino leonardo vs uno

The Arduino UNO is a popular microcontroller board used for all kinds of neat applications and bases on ATmega328 category. It has 28 digital I/O pins and 12 analog inputs. The board operates at 16MHz with a USB on-the-board system with one USB cable. We can program it using the Arduino software. It allows you to write sketches for your project in C++. We place the ATmega328P microcontroller on the top of the PCB, and has 2KB Flash memory and 2KB RAM. One can power the Arduino UNO up using a USB port.

The Arduino UNO first appeared in 2005. David Cuartielles, Gianluca Martino, and Tom Igoe improved it. This Arduino board has a DIP socket to accept a microcontroller. Depending on the selected microcontroller, you must use the right microcontroller on your project. It could either work or not work at all.

Arduino UNO advantages

The Arduino UNO has many uses and is excellent for beginners. It is easy to use, making programming in a new language quick and easy. We use the Arduino UNO to make various robots, automatons, and much more. The Arduino software works on most operating systems. So, you do not have to worry about whether your computer can program the board or not.

We use the Arduino UNO to make various projects such as robots, automatons, and much more.

It is not difficult to use Arduino UNO. The memory supplied with the board helps beginners learn about using microcontrollers. It also helps them learn to program it using the C language. Beginners can also learn about transferring their programs. They do it through the USB cable on the Arduino UNO from their computer to the board. Besides, they do not need to remove or replace any components.

Arduino UNO disadvantages

The Arduino UNO is not ideal for complex projects. It would be difficult to use if you’re trying to do a project that needs much control over timing. Arduino UNO has very few pins, making it less useful for complex projects. It is also not meant to use an external power source as the Arduino UNO does not have an onboard power regulator. We designed the Arduino UNO as a microcontroller debugger and introduced microcontrollers. So, you should not use this board for anything other than introductory projects.

Arduino UNO Components

The Arduino UNO uses a microcontroller board. We place the board on the top of the mainboard and have diodes protecting it from any ESD damage. These diodes are there to protect the microcontroller from any unwanted surges. These surges may cause problems on the circuit. It also has a crystal oscillator, which helps trigger and divide circuits on the board.

The ATMEGA328P microcontroller used in this Arduino UNO is an 8-bit microchip. It has a maximum clock speed of 20MHz. This microcontroller has an instruction RAM of 2KB. It helps execute commands on the microcontroller. It also has an EEPROM, which stores any information even when the power supply is off.

The Arduino UNO has a voltage regulator. It allows it to receive power from either an internal or external power source. The UNO operates at a voltage range between 7V – 12V, and as soon as the voltage drops below 7V, it will stop working.

Arduino UNO Pinout

The Arduino UNO is a miniaturized version of the Arduino family. We use it to create interactive objects and devices. They include robots, automation, security cameras, and much more. 

Arduino UNO has changed how we use microcontrollers. It has become a standard tool for some beginners and advanced programmers. In addition, it has a wide range of attributes that allow it to function in various ways.

The Arduino UNO has an official pinout which we use to indicate the location of each pin on the board:

Name Type Description

Arduino Pin 1 Digital PWM Digital Output 0–5V, Arduino Pin 2 Digital PWM Digital Output 0–5V, Arduino Pin 3 Digital PWM Digital Output 0–5V, Arduino Pin 4 Digital PWM Digital Output 0–5V, Arduino Pin 5 VCC Power Supply 5V, and Arduino Pin 6 GND Ground Ground (0V)

How to Program Arduino UNO

We can program the Arduino UNO using the Arduino IDE software. You can download this software from its official website. It is also available in a repository of the Arduino organization. The software is compatible with Windows, Mac, and Linux systems.

You first need to download and install the software on your system. Then you can open the Arduino IDE by following these steps:

You need to create an account to download the source code, upload sketches and log onto your account.

Arduino UNO Programming

The Arduino programming language is C++. C++ is a high-level and multi-paradigm programming language. It supports procedural programming, data abstraction, and object-oriented programming. Unlike Java, it is like Java, but we can use it on small and large projects.

Arduino Code

Here is an example of the Arduino code:

#include <Servo.h> Servo myservo;

int pos = 90;

// variable to store the servo position void setup()

{ // put your setup code here, to run once: myservo.attach(9); }

void loop()

{ // put your main code here, to run repeatedly: myservo.write(pos); delay(15); }

This code will output the value 90 in a loop of 15ms at pin 9. The delay function allows the microcontroller to execute another instruction. It executes the code after a specified amount of time.

The programming language allows you to program the microcontroller using C or C++. The Arduino programming language uses the same syntax as C++, but we do not use some additions in C++.

Arduino UNO Application

There are many Arduino applications in the world. These applications range from simple devices to complex systems. They include clocks, projectors, system controllers, robotic projects, and Media Players. When writing your Arduino code, ensure that you follow the tutorials. You can find them on the internet to do a good project.

Before starting with Arduino programming, learn to use a breadboard to connect many components. Make them work together.

Weighing Machines:

These are among the most common projects that people use for Arduino Programming. We can use sensors in these projects. They range from touch and pressure sensors to force and temperature sensors.

Traffic Light Count Down Timer:

These are also often used in Arduino projects. For example, it works best in a traffic light countdown timer. The Arduino microcontroller gets connected with relays and lights at different times. But, first, we connect the Arduino microcontroller to the relays, activating the lights.

Temperature Alarms:

This is a common application of Arduino Programming that we can use for home automation. For example, temperature alarms are helpful when you want to know if someone is coming home soon. You can also use it to know if your food is ready for consumption.

Parking Lot Counter:

These devices help count and report the number of vehicles parked in a parking lot. We use them in parking lots, so they should count only the cars coming to park there.

Embedded systems:

You can use Arduino to create an application that performs calculations. Applications that interact with the outside world can also work with Arduino. For example, we use them in Medical Systems and Networking Devices.

Home Automation:

This is another common application of Arduino Programming. For example, home Automation uses Arduino to automate things without human intervention. A typical example would be the lights turned off when a particular person enters the room.

Industrial Automation:

Industrial automation is a widespread application of Arduino Programming. It involves the creation of large industrial robots. However, they are quite complex, and only experts can program them.

Medical Instrument:

Medical instruments can help in the diagnosis and treatment of patients. These devices range from simple machines to more complex systems. They include blood glucose monitors and pacemakers.

Emergency Light for Railways:

These devices are essential in the safe continuation of trains after a blocked track by an accident or a person. We must connect these devices with relays to activate the lights when a train has hit the barrier.

Arduino Leonardo vs UNO

The differences between Arduino UNO and Leonardo mainly lie in their physical connections. For example, the Arduino UNO is compatible with the Arduino IDE, while the Leonardo is not. In addition, Leonardo uses an AVR core which is different from the one used in the Arduino UNO.

1. ATmega Microcontroller

The Arduino UNO and Leonardo are both based on an AVR microcontroller. This microcontroller is helpful in a wide range of electronic appliances. The main difference between the Arduino UNO and Leonardo is that the latter uses an ATmega microcontroller. Therefore, we can use it for advanced applications.

2. Microcontroller remove-ability

The Arduino UNO depends on an ATmega328 microcontroller. Therefore, we cannot remove it from the board. However, the Leonardo depends on an ATmega32u4 microcontroller. Consequently, we can remove it from the board since it uses a different socket than the Arduino UNO.

3. Input/output pins

The Arduino UNO has 13 digital input/output pins and six analog input pins. These pins can connect the Arduino with external devices. They use terminal blocks, wire, or solderless breadboards. On the other hand, the Leonardo has 20 digital input/output pins and 12 analog input pins. We connect them using a long edge connector that looks like a USB connector.

4. Pulse Width Modulation Pins

The Arduino UNO and Leonardo both use the same pins that we can use to connect external devices. The only difference is that Leonardo uses the Pulse Width Modulation technique. This technique allows the microcontroller to deliver a control signal of different widths.

5. Price

While the Arduino UNO costs less than $25, the Leonardo costs more than $45. The actual price of the Arduino UNO ranges from $20 to $30, while that of the Leonardo ranges from $65 to $85.

6. USB Support

Both the Arduino UNO and Leonardo support USB communications using the USB standard. The pinouts of both the boards look alike. But there are some differences in how they communicate with a host computer. For example, the Arduino UNO has an FTDI chip. The Leonardo uses an Atmel microcontroller.

7. Flexibility to support protocols other than UART

The Arduino UNO supports only a few protocols such as UART (Serial port), I2C, and SPI. However, the Leonardo has three expansion ports. We can use them to connect it with external devices. One of these ports is UART, which can communicate with the computer. Two of these expansion ports are high-speed I2C and SPI with built-in buffers.


The Arduino UNO and Leonardo are both microcontroller boards. They can perform a wide range of applications. However, the Arduino UNO is cheaper than the Leonardo. It has an ATmega328 microcontroller. The latter is a bit costly but supports more advanced features.

The decision of which board to use will depend on several factors. First, you should decide if you want to spend more and support more advanced features or if you want to save money. We can use both boards for industrial projects, home automation, and embedded systems.