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Arduino Leonardo without Headers

SKU A000052 Barcode 7630049200326 Show more
Original price €0
Original price €23,02 - Original price €23,02
Original price
Current price €23,02
€23,02 - €23,02
Current price €23,02
VAT included

The classic Arduino board that can act as a mouse or keyboard.

Overview

The Arduino Leonardo is a microcontroller board based on the ATmega32u4 (datasheet). It has 20 digital input/output pins (of which 7 can be used as PWM outputs and 12 as analog inputs), a 16 MHz crystal oscillator, a micro USB connection, a power jack, an ICSP header, and a reset button. It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or battery to get started.

The Leonardo differs from all preceding boards in that the ATmega32u4 has built-in USB communication, eliminating the need for a secondary processor. This allows the Leonardo to appear to a connected computer as a mouse and keyboard, in addition to a virtual (CDC) serial / COM port. It also has other implications for the behavior of the board; these are detailed on the Getting started with the Arduino Leonardo.

Related Boards

If you are interested in boards with similar functionality, at Arduino you can find:

Getting started

Find inspiration for your projects with Leonardo board from our tutorial platform Project Hub.

The Getting started with the Arduino Leonardopage contains all the information you need to configure your board, use the Arduino Software (IDE), and start tinkering with coding and electronics.

From the Tutorials section you can find examples from libraries and built-in sketches as well other useful information to expand your knowledge of the Arduino hardware and software.

Need Help?

Check the Arduino Forum for questions about the Arduino Language, or how to make your own Projects with Arduino. Need any help with your board please get in touch with the official Arduino User Support as explained in our Contact Us page.

Warranty

You can find here your board warranty information.


Tech specs

Microcontroller ATmega32u4
Operating Voltage 5V
Input Voltage (Recommended) 7-12V
Input Voltage (limits) 6-20V
Digital I/O Pins 20
PWM Channels 7
Analog Input Channels 12
DC Current per I/O Pin 40 mA
DC Current for 3.3V Pin 50 mA
Flash Memory 32 KB (ATmega32u4) of which 4 KB used by bootloader
SRAM 2.5 KB (ATmega32u4)
EEPROM 1 KB (ATmega32u4)
Clock Speed 16 MHz
Lengh 68.6 mm
Width 53.3 mm
Weight 20 g

Conformities

The following Declarations of Conformities have been granted for this board:
REACH
CE
UKCA
FCC
For any further information about our certifications please visit docs.arduino.cc/certifications

Resources for Safety and Products

Manufacturer Information

The production information includes the address and related details of the product manufacturer.

Arduino S.r.l.
Via Andrea Appiani, 25
Monza, MB, IT, 20900
https://www.arduino.cc/ 

Responsible Person in the EU

An EU-based economic operator who ensures the product's compliance with the required regulations.

Arduino S.r.l.
Via Andrea Appiani, 25
Monza, MB, IT, 20900
Phone: +39 0113157477
Email: support@arduino.cc

 

Documentation

OSH: Schematics

The Arduino Leonardo is open-source hardware! You can build your own board using the following files:

EAGLE FILES IN .ZIP SCHEMATICS IN .PDF

Pinout Diagram

Download the full pinout diagram as PDF here.

Interactive Board Viewer

Interactive Board Viewer

 

Get Inspired

PROJECT HUB
Arduino Bluetooth Tank
Arduino Bluetooth Tank
Project Tutorial by mastoras_inc

I'm excited to share the details of my BT Arduino Tank project, which incorporates some impressive 3D-printed components. While the main chassis of the tank was not 3D-printed, I utilized this technology to create two crucial parts: the enclosure for the motor driver and the compartment housing the remaining electronics. Additionally, I 3D-printed a cannon for an added touch of customization. The enclosure for the motor driver served as a protective housing, ensuring that the L298N motor driver module was securely mounted and shielded from external elements. By designing and 3D-printing this part, I could precisely fit it to the tank's specifications, providing a neat and organized arrangement of the electronics. In the same vein, the compartment for the remaining electronics, such as the Arduino Nano Every and the HC-05 Bluetooth module, was also 3D-printed. This enclosure offered a clean and organized solution for housing these components, safeguarding them while maintaining easy access for maintenance or modifications. Lastly, to enhance the tank's appearance and add a touch of personalization, I designed and 3D-printed a cannon. This custom-printed cannon perfectly complemented the overall design, making the tank even more visually appealing. By strategically incorporating 3D printing into specific parts of the project, I achieved a balance between functionality and customization. The precision and versatility of 3D printing allowed me to create tailored enclosures and a unique cannon, elevating the overall aesthetic and practicality of my BT Arduino Tank project.

read more
BLOG
Arduino Nano Every brings Knight Rider sound effects to Knight Rider RC car
Arduino Nano Every brings Knight Rider sound effects to Knight Rider RC car
February 14, 2023

KITT (Knight Industries Two Thousand) was a fictional car based on a 1982 Pontiac Trans Am in the Knight Rider television series. KITT featured an artificial intelligence, voiced by the legendary William Daniels, and some iconic styling. Savall21 built a replica RC KITT and used Arduino boards to add sound and light effects that he can trigger with the RC transmitter. This is a custom RC car created by Savall21 using a Tamiya TT-02 kit and a resin 3D-printed body shell. The controller/transmitter is a Jumper T18, which has a customizable touchscreen interface. Savall21 programmed his own widget for that touchscreen. It mimics the fictional KITT control panel and lets the user select different sound effects and activate the iconic headlights. The T18 sends commands to an FrSky XR8 radio receiver located in the car. The FrSky receiver communicates with two Arduino Nano Every boards via the S.Port. The first Arduino controls the sound effects, which play through a DFPlayer Mini MP3 player module. The FrSky receiver simply sends a numerical code to the Arduino, which then activates the corresponding audio clip. The second Arduino drives a strip of WS2812B individually addressable RGB LEDs for the headlights and taillights. The user can control the headlights directly, while the taillights automatically come on any time the throttle is below 50%. For fans of Knight Rider and RC vehicles, this is the ultimate project. The car looks fantastic and the Arduino effects add polish to the build.

read more

FAQs

Power

The Arduino Leonardo can be powered via the micro USB connection or with an external power supply. The power source is selected automatically. 
External (non-USB) power can come either from an AC-to-DC adapter (wall-wart) or battery. The adapter can be connected by plugging a 2.1mm center-positive plug into the board's power jack. Leads from a battery can be inserted in the Gnd and Vin pin headers of the POWER connector. 
The power pins are as follows: 

  • VIN. The input voltage to the Arduino board when it's using an external power source (as opposed to 5 volts from the USB connection or other regulated power source). You can supply voltage through this pin, or, if supplying voltage via the power jack, access it through this pin.
  • 5V. The regulated power supply used to power the microcontroller and other components on the board. This can come either from VIN via an on-board regulator, or be supplied by USB or another regulated 5V supply.
  • 3V3. A 3.3 volt supply generated by the on-board regulator. Maximum current draw is 50 mA.
  • GND. Ground pins.
  • IOREF. The voltage at which the i/o pins of the board are operating (i.e. VCC for the board). This is 5V on the Leonardo.

Memory

The ATmega32u4 has 32 KB (with 4 KB used for the bootloader). It also has 2.5 KB of SRAM and 1 KB of EEPROM (which can be read and written with the EEPROM library). 

Input and Output

Each of the 20 digital i/o pins on the Leonardo can be used as an input or output, usingpinMode()digitalWrite(), and digitalRead() functions. They operate at 5 volts. Each pin can provide or receive a maximum of 40 mA and has an internal pull-up resistor (disconnected by default) of 20-50 kOhms. In addition, some pins have specialized functions:

  • Serial: 0 (RX) and 1 (TX). Used to receive (RX) and transmit (TX) TTL serial data using theATmega32U4 hardware serial capability. Note that on the Leonardo, the Serial class refers to USB (CDC) communication; for TTL serial on pins 0 and 1, use the Serial1 class.
  • TWI: 2 (SDA) and 3 (SCL). Support TWI communication using the Wire library.
  • External Interrupts: 3 (interrupt 0), 2 (interrupt 1), 0 (interrupt 2), 1 (interrupt 3) and 7 (interrupt 4). These pins can be configured to trigger an interrupt on a low value, a rising or falling edge, or a change in value. See the attachInterrupt() function for details.
  • PWM: 3, 5, 6, 9, 10, 11, and 13. Provide 8-bit PWM output with the analogWrite() function.
  • SPI: on the ICSP header. These pins support SPI communication using the SPI library. Note that the SPI pins are not connected to any of the digital I/O pins as they are on the Uno, They are only available on the ICSP connector. This means that if you have a shield that uses SPI, but does NOT have a 6-pin ICSP connector that connects to the Leonardo's 6-pin ICSP header, the shield will not work.
  • LED: 13. There is a built-in LED connected to digital pin 13. When the pin is HIGH value, the LED is on, when the pin is LOW, it's off.
  • Analog Inputs: A0-A5, A6 - A11 (on digital pins 4, 6, 8, 9, 10, and 12). The Leonardo has 12 analog inputs, labeled A0 through A11, all of which can also be used as digital i/o. Pins A0-A5 appear in the same locations as on the Uno; inputs A6-A11 are on digital i/o pins 4, 6, 8, 9, 10, and 12 respectively. Each analog input provide 10 bits of resolution (i.e. 1024 different values). By default the analog inputs measure from ground to 5 volts, though is it possible to change the upper end of their range using the AREF pin and the analogReference() function.

There are a couple of other pins on the board:

  • AREF. Reference voltage for the analog inputs. Used with analogReference().
  • Reset. Bring this line LOW to reset the microcontroller. Typically used to add a reset button to shields which block the one on the board.

See also the mapping between Arduino pins and ATmega32u4 ports

Communication

The Leonardo has a number of facilities for communicating with a computer, another Arduino, or other microcontrollers. The ATmega32U4 provides UART TTL (5V) serial communication, which is available on digital pins 0 (RX) and 1 (TX). The 32U4 also allows for serial (CDC) communication over USB and appears as a virtual com port to software on the computer. The chip also acts as a full speed USB 2.0 device, using standard USB COM drivers. On Windows, a .inf file is required. The Arduino software includes a serial monitor which allows simple textual data to be sent to and from the Arduino board. The RX and TX LEDs on the board will flash when data is being transmitted via the USB connection to the computer (but not for serial communication on pins 0 and 1). A SoftwareSerial library allows for serial communication on any of the Leonardo's digital pins. The ATmega32U4 also supports I2C (TWI) and SPI communication. The Arduino software includes a Wire library to simplify use of the I2C bus; see the documentation for details. For SPI communication, use the SPI library. The Leonardo appears as a generic keyboard and mouse, and can be programmed to control these input devices using the Keyboard and Mouse classes. 

Programming

The Leonardo can be programmed with the Arduino software (download). Select "Arduino Leonardo from the Tools > Board menu (according to the microcontroller on your board). For details, see the reference and tutorials. The ATmega32U4 on the Arduino Leonardo comes preburned with a bootloader that allows you to upload new code to it without the use of an external hardware programmer. It communicates using the AVR109 protocol. You can also bypass the bootloader and program the microcontroller through the ICSP (In-Circuit Serial Programming) header using Arduino ISP or similar; see these instructions for details. 

Automatic (Software) Reset and Bootloader Initiation

Rather than requiring a physical press of the reset button before an upload, the Leonardo is designed in a way that allows it to be reset by software running on a connected computer. The reset is triggered when the Leonardo's virtual (CDC) serial / COM port is opened at 1200 baud and then closed. When this happens, the processor will reset, breaking the USB connection to the computer (meaning that the virtual serial / COM port will disappear). After the processor resets, the bootloader starts, remaining active for about 8 seconds. The bootloader can also be initiated by pressing the reset button on the Leonardo. Note that when the board first powers up, it will jump straight to the user sketch, if present, rather than initiating the bootloader. 
Because of the way the Leonardo handles reset it's best to let the Arduino software try to initiate the reset before uploading, especially if you are in the habit of pressing the reset button before uploading on other boards. If the software can't reset the board you can always start the bootloader by pressing the reset button on the board. 

USB Overcurrent Protection

The Leonardo has a resettable polyfuse that protects your computer's USB ports from shorts and overcurrent. Although most computers provide their own internal protection, the fuse provides an extra layer of protection. If more than 500 mA is applied to the USB port, the fuse will automatically break the connection until the short or overload is removed. 

Physical Characteristics

The maximum length and width of the Leonardo PCB are 2.7 and 2.1 inches respectively, with the USB connector and power jack extending beyond the former dimension. Four screw holes allow the board to be attached to a surface or case. Note that the distance between digital pins 7 and 8 is 160 mil (0.16"), not an even multiple of the 100 mil spacing of the other pins.

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