7

Build your own Arduino

TUTORIAL

Make your projects Arduino-compatible

Build your own Arduino

he Arduino Uno is a great board for

prototyping with; however, it’s bulky

and a little pricey. This is because it

comes with a whole bunch of stuff you

might not need, such as a USB to serial

converter and a large number of exposed

headers. You can incorporate the core processing

component from the Arduino Uno (an ATmega328P)

and make it programmable from the Arduino IDE in a

smaller, cheaper, and more flexible way. That’s what

we’re doing with our ‘standalone’ Arduino.

The idea of the ‘standalone Arduino’ is to get rid

of all the components included in the development

board (Arduino Uno) that you just don’t need. So you

are left with a 16MHz crystal oscillator, a voltage

regulator, four capacitors, and the ATmega328P chip,

plus all the extra components that your project will

need. You can build the circuit either on a solderless

breadboard, a soldered protoboard, or a printed circuit

board (PCB). The last two options are better suited for

final projects, as they are more durable and resistant.

Before setting up the standalone Arduino in your

circuit, you will need to burn the bootloader on the

ATmega328P chip and program it with the Arduino

code. The easiest way to do this is by means of

the Arduino Uno. The connections between the

Arduino Uno and the standalone Arduino will be

different for bootloading and programming, so it

is recommended to perform these two tasks on a

solderless breadboard.

GETTING BURNED

Table 1 shows the connections between the Arduino

Uno and the standalone Arduino chip (ATmega328P)

for bootloading.

First, you have to load the ArduinoISP sketch on the

Arduino Uno with the Arduino IDE (File > Examples >

ArduinoISP). Then you have to select Tools > Board

> Arduino/Genuino Uno, and burn the bootloader

onto the ATmega328P chip: Tools > Burn Bootloader.

The bootloading process will take several seconds

to complete.

Once the standalone Arduino chip has the

bootloader burned, it is time to program it with the

Arduino code. We’ll do this via the Uno, but in order

to make sure that we program our separate chip, not

T

Table 1

The connections between the Uno and the raw ATMega328P.

Chip pin numbers are counted anti-clockwise, starting with the

pin immediately anti-clockwise of the U-shaped notch

Ricardo

Caja Calleja

An aerospace engineer

by profession, Ricardo

is deeply interested

in robotics and

automation. If there’s

nothing to repair at

home, he’ll make up

some plan to build

anything that includes

cables or screws.

funwithcables.wordpress.com

ARDUINO

UNO PIN

ATMEGA328P

CHIP PIN

5 V 7, 20

GND 8, 22

10 1

11 17

12 18

13 19

1

1

5

5

10

10

15

15

20

20

25

25

30

30

35

35

40

40

45

45

50

50

55

55

60

60

AB AB

CD CD

E E

FG FG

H H

IJ IJ

1312111098 765432

L

5V A0

ANALOG IN

AREF

1

GND

TXRX

RESET3V3 GNDGNDVIN A1A2A3A4A5

DIGITAL (PWM= )

Arduino TM

IOREF

ICSP

ICSP2

ON

POWER

10

RESET TX0RX0

ATMEGA328

Above

Burning the

bootloader