Arduino Uno Manual

Here is a new book for all Arduino enthusiasts – the Arduino Uno Hardware Manual. This Arduino Uno Manual is a reference and user guide for the Arduino Uno hardware and firmware.

Pictured below are two copies of the new manual fresh off the press, published in 2019.

Arduino Uno manual
The Arduino Uno Hardware Manual – a Handy Reference and User Guide

Arduino Uno Manual Hardware Reference

The Arduino Uno Hardware Manual is ideal as a workbench reference for any Arduino user. It provides interesting and vital information on wiring circuits to an Arduino Uno. Good engineering practice, which includes properly calculating current that can be drawn per pin, is included. Current limits per pin are not as simple as quoting a maximum current that can be drawn per pin. Groups of pins have certain current limits in addition to limits per pin in the group. This is well explained in the manual. Figures and illustrations throughout the book help in understanding various hardware concepts.

Arduino Uno Hardware Manual on the workbench
Arduino Uno Hardware Manual in use on the Workbench

The manual includes Arduino Uno pin mapping to the ATmega328P microcontroller and a pin reference that explains the function of each pin. Interfacing examples show the use of each type of pin. This includes SPI, TWI, UART and PWM pins.

Fault Finding, Repair and Firmware

Basic fault finding techniques in the manual show how to test an Arduino Uno to see if it is faulty or working. Repair procedures show how to replace the ATmega328P microcontroller should it be faulty. Firmware must be loaded to a new microcontroller on an Arduino Uno so that it will work with the Arduino IDE programming environment. Firmware restoration and testing procedures are explained.

Programming Headers and External Programmers

The manual shows how to program both the ATmega32P and ATmega16U2 microcontrollers using external programmers, and explains why and when you would want to do this.

Arduino Uno Parts List, Circuit Diagram and Part Location

A parts list can be found in the Arduino Uno Hardware Manual which includes the new parts added to the recently updated Arduino Uno R3, the Rev3e version. Easily located parts or components on the Arduino Uno using the component position diagram. Find the same part in the circuit diagram, which is broken up into three easy to understand parts.

Extending Hardware, Handling Precautions and Technical Information

Learn about various methods of extending the Arduino Uno hardware, and adding external memory. Handling precautions explain how to avoid damaging an Arduino Uno during use and storage. Technical information such as memory types and sizes, power supply information, operating frequency, meaning of the on-board indicator LEDs, and pins that are shared between functions and connectors can all be found in the Hardware Technical Information chapter.

More Details on the Arduino Uno Hardware Manual

Visit the Arduino Uno Hardware Manual page on the publisher’s website for more information on this excellent book. Here you can find:

PWM on an Oscilloscope

What PWM looks like on an oscilloscope. PWM is Pulse Width Modulation which can be used to change the brightness of an LED. This article and video shows PWM on an oscilloscope by using the Fade example sketch or program from the Arduino IDE. An LED and series resistor is connected to an Arduino Uno pin and the Arduino sketch continually adjusts the brightness of the LED by using PWM on the pin.

Video Showing PWM on an Oscilloscope

The following video shows PWM on an oscilloscope that is continually changing in order to change the brightness of the LED. Both the LED and Arduino Uno can be seen in the inset video. PicoScope is a PC based oscilloscope that connects to the USB port of a computer. Software running on the computer acts as the oscilloscope screen and control panel and can be seen in the video.

Hardware and Software for the PWM Demo

Find the Fade sketch in the Arduino IDE under File → Examples → 01.Basics → Fade from the top menu. The oscilloscope GND is connected to the Arduino GND. Pin 9 of the Arduino is used as the measurement point to measure the PWM waveform on the oscilloscope. The image below shows how the LED and series resistor are connected to the Arduino Uno. For more information, see the related Fade tutorial on the Arduino website.

Fade Arduino Example used to Show PWM on an Oscilloscope

Fade Arduino Example used to Show PWM on an Oscilloscope

How PWM Works

PWM changes the duty cycle of a square wave, which means that it changes the ratio of its on time to its off time. When the square wave is on, or at 5V, for longer than it is off, the LED will burn brighter. If the square wave is off, or at GND, for longer than it is on, the LED will burn dimmer.

Duty cycle of a PWM waveform is usually given as a percentage. If the duty cycle is 80%, then the on cycle of the square wave is on for 80% of the time and off for 20% of the time. A square wave with a 50% duty cycle has an equal on and off time.


Choosing an Arduino for Beginners

In this blog post we look at how beginners wanting to start with Arduino can choose an Arduino board. Help is provided for beginners choosing an Arduino. The difference between an Arduino and AVR ATmega microcontroller is also covered.

Choosing an Arduino for Beginners

The recommended Arduino for beginners is usually the Arduino Uno. On the Starting Electronics website, the article on choosing an Arduino for beginners provides more information on which Arduino to choose when starting to learn about Arduino and writing sketches.

Difference Between Arduino and AVR

Many Arduino beginners are confused about the difference between Arduino and AVR, or Arduino and ATmega. Difference between Arduino and ATmega328 explains what the ATmega328 microcontroller is and how it relates to the Arduino Uno. The article also explains more about the AVR microcontroller found on most Arduino boards.

Arduino Projects for Beginners

A list of easy to build Arduino projects for beginners and kids. These projects use easy to obtain components and can be built on an electronics breadboard. Suitable for use with an Arduino Uno or similar board.

Arduino projects for absolute beginners below list very easy projects for first time Arduino users. The section that follows lists projects for beginners who have learned the basics of how to use an Arduino.

Arduino Projects for Absolute Beginners

The simple projects below are suitable for absolute beginners with Arduino. They are part of a series of tutorials that introduce beginners to basic electronics. For beginners who have not yet used an electronics breadboard, see how to build a simple circuit on breadboard.

Arduino Projects for Beginners

The Arduino projects for beginners area on the Starting Electronics website has various projects for beginners such as:

Other projects suitable for beginners:

Programming Arduino

Beginners wanting to learn how to program Arduino can look at the Arduino programming course.

Arduino Ethernet Shield

For those wanting to know how to use the Arduino Ethernet shield as  a web server, the Arduino Ethernet shield web server tutorial explains all you need to know.

Other Arduino Resources

Also see the following areas on the Starting Electronics website:

  • Arduino Projects – various Arduino projects for beginners and more advanced users.
  • Arduino Tutorials –  interesting Arduino tutorials.
  • Arduino Articles – various articles and small projects such as how to battery power an Arduino, connecting a buzzer to Arduino, using Arduino to measure voltage and more.
  • Arduino Software – various Arduino software projects and information on installing Arduino software.

Another useful resource for projects is the Arduino tutorials page on the Arduino website.

Moving Light Display Arduino Project for Beginners

This easy Arduino project for beginners can be built on an electronic breadboard and uses only four LEDs and four series resistors to make a moving light display. The Arduino sketch for the project can be modified to change the rate at which the pattern on the LEDs is updated. The patterns to display on the LEDs can also be changed.

Moving Light Display Arduino Project for Beginners

Moving Light Display Arduino Project for Beginners

Details of this Arduino Project for Beginners

A breadboard is used to connect four LEDs with series resistors to an Arduino which can be an Arduino Uno or other Arduino. Four wire links connect the LEDs to four of the Arduino pins which are set as outputs. A common GND wire from the Arduino is connected to the breadboard which connects the other side of each of the series resistors to GND. This completes the circuit and enables the LEDs to be switched on by the sketch running on the Arduino.

Moving LED Arduino Project

Moving LED Arduino Project

The full project includes the circuit diagram, Arduino sketch code and instructions on how to modify the sketch to display different moving light LED patterns on the LEDs.

Other Arduino Beginner Project Resources

Those new to Arduino may be interested in the beginners electronics series of tutorials that includes an introduction to Arduino.

The same tutorial series includes ten Arduino projects for absolute beginners which is a sample of various Arduino built-in examples with instructions on how to build each project.