CSEduino - Build your Arduino from scratch

Build your Arduino from scratch

João Alves (jpralves@gmail.com)Version 1.0 - Mar 2014

AgendaIntroductionProblemSolutionRequirementsSchematicsBill of Materials

The PartsAssembling the boardRunning a Test SketchDemo

IntroductionSoldered my first Arduino Clone - a Diavolino (http://wiki.evilmadscientist.com/Diavolino) - in 2012 in a workshop presented by Mitch Altman at Codebits.

Introduction (cont…)After some other workshops in Altlab (http://altlab.org) where I assembled a Freeduino and made some small stripboards with leds, buzzers and buttons I wanted to do more and start learning not only the how but also the why in electronics. This is one of my works, based on several other similar projects found on the Internet.You are free to use it, change it and improve it.

ProblemArduino is very nice for prototyping but after creating a project with the board it is an overkill to use it in the final product. Although not very expensive, an Arduino clone board costs at least € 20 (25 USD), an official one costs a little bit more.

Solution

Create an inexpensive Arduino-like board that can be used with the project keeping the Arduino Board for future projects.

It can replace completely the Arduino board if you don’t require the use of shields (it is not pin head compatible).

Requirements

● Cheap● Small● Easy

CheapWith a very small budget of up to € 3.5 (5 USD) in parts it was possible to build this board with the required components.

SmallTo be small some optimizations were made to the stripboard to accomplish its reduced size. The board is 4.5cm x 5.5cm.The circuit is adaptable to different requirements and it was made modular enough to be able remove the parts not needed and reduce its size even further.

EasyTo be simple and easy to build I’ve used only THT - Through-hole technology. Avoiding SMD - Surface Mount Devices - components - as they are harder to solder and prone to errors. I’ve used the most common microcontroller used in Arduino Boards with THT - the ATMega328P (in PDIP format). The components where soldered to a stripboard to reduce extra wiring.

Schematics

Bill of Materials● 1x Stripboard with at least 19 Rows and 16

Columns (€ 0,73)

● 1x ATmega328P-PU microcontroller with

Arduino bootloader (U1) (€ 1,59)

● 1x 28 pin DIP IC Socket (U1)

● 1x 16 MHz crystal oscillator (XTAL1) (€ 0,44)

● 2x 22 pF, 50 V ceramic capacitors (C3, C4)

(€ 0,06)

● 1x 40-pin male single header (J1, J2, J3, J4,

J5, J6, J7) (€ 0,12)

● 1x 7805 linear voltage regulator (U2) (€ 0,22)

● 2x 100 μF, 25 V electrolytic capacitors

(C1, C2) (€ 0,04)

● 1x 1N4001 rectifier diode (D1) (€ 0,02)

● 1x SPST momentary normally-open type

switch (S1) € 0,08)

● 1x 10 kΩ resistor (R2) (€ 0,01)

● 1x 100 nF, 50 V ceramic capacitor (C5) (€

0,06)

● 1x 1 kΩ resistor (R1) (€ 0,01)

● 1x LED (3mm) (LED1) (€ 0,02)

● 1x Jumper (€ 0,01)

The Parts

● Voltage Regulator● USB/FTDI Programming Header● Hello World LED● Microcontroller

The Voltage Regulator

Components:● 1x 7805 linear voltage

regulator (U2)● 2x 100 μF 25 V electrolytic

capacitors (C1, C2)● 1x 1N4001 rectifier diode

(D1)● 1x 5-pin male single

header (J5 + J6)

USB/FTDI Prog. Header

Components:● 1x SPST normally-open

type switch (S1)● 1x 10 kΩ resistor (R2)● 1x 100 nF, 50 V ceramic

capacitor (C5)● 1x 6-pin male single

header (J4)

Hello World LED

Components:● 1x 1 kΩ resistor (R1)● 1x LED (3mm) (LED1)● 1x Jumper● 1x 2-pin male single

header (J7)

MicrocontrollerComponents:● 1x ATmega328P-PU microcontroller

(U1)● 1x 28 pin DIP IC Socket (U1)● 1x 16 MHz crystal oscillator (XTAL)● 2x 22 pF, 50 V ceramic capacitors

(C3, C4)● 1x 14-pin male single header (J1)● 1x 7-pin male single header (J2)● 1x 4-pin male single header (J3)

The ATmega328P Pin Layout

Assembling the board

● Tools required for assembling● Preparing for the Assembly● Cut holes in the stripboard● Cut 40-Pin Header into smaller parts● Soldering components

Tools required for assembling

● Soldering Iron● Track Cutter● Wire Snips● X-Acto Knife● Solder

Preparing for the AssemblyCommon stripboards have one side with the “stripes” and another clean side. The components will be mounted on the clean side and soldered on the strip side.

Cut holes in the stripboard

Prepare 40-Pin Male HeaderCut the 40-Pin Male to this sizes:● 1x 14-pin male single header (J1)● 1x 8-pin male single header (J2)● 1x 4-pin male single header (J3)● 1x 6-pin male single header (J4)● 1x 5-pin male single header (J5 + J6)● 1x 2-pin male single header (J7)

Soldering componentsSolder the components in the following order:● Wires● IC Socket (U1)● Resistors (R1, R2)● 1N4001 (D1)● Ceramic Capacitors (C3, C4, C5)● Crystal (XTAL)● SPST switch (S1)

● Male Head Pins (J1, J2, J3, J4, J5, J6, J7)

● LED (LED1) ● Electrolytic Capacitors (C1, C2) ● 7805 (U2) ● ATmega328P (U1)

Components location

● IC Socket and ATmega328P-PU (U1)● 16 MHz Crystal (XTAL1)● 22 pF, 50 V (C3, C4)● 7805 (U2) ● 100 μF, 25 V (C1, C2)● 1N4001 (D1) ● SPST switch (S1) ● 10 kΩ resistor (R2) ● 100 nF, 50 V (C5)● 1 kΩ resistor (R1) ● LED (3mm) (LED1)

C5

C3

C1 C2

C4

XTAL1

S1 U1

U2 D1

LED1

R1

R2

FTDI

POWER

Soldering components locationAfter each component there are coordinates LyCx where y is the line and x is the column to put the wire.The lines and columns are numbered on the strip side so the x is backwards.

x

y

WiresCut wires with the following lengths:

● Black:○ 2 x 3 cm (L4C3-L12C3, L4C8-L13C8)○ 1 x 1 cm (L2C9-L4C9)

● Red:○ 2 x 3 cm (L5C2-L14C2, L5C6-L12C6)○ 2 x 1 cm (L3C12-L5C12, L5C14-L6C15)

● Green:○ 1 x 3,5 cm (L3C5-L15C5)

● Yellow: ○ 1 x 3 cm (L6C13-L11C16)

Solder the wires into the stripboard according to the image.

IC Socket (U1)Place the IC Socket with pin 1 on the top.Its not very easy to solder because the two wires below get in the way. Try to center the wires under the socket. Solder carefully according to the image.

Components:● U1 - 28 pin DIP IC Socket (L6C7 - L19C4)

Resistors (R1, R2)The Resistors don’t have polarity but R1 is different from R2. Solder carefully according to the image.

Components:● R1 - 1 kΩ resistor (L3C3 - L2C5)● R2 - 10 kΩ resistor (L6C9 - L12C9)

1N4001 (D1)Solder the component in the board with the stripe (-) on the left.

Components:● D1 - 1N4001 rectifier diode (L1C2 - L1C5)

Ceramic Capacitors (C3, C4, C5)The Ceramic Capacitors don’t have polarity but C5 is different from C3 and C4. Solder carefully according to the image.

Components:● C3 - 22 pF, 50 V ceramic capacitor (L13C11 - L15C11)● C4 - 22 pF, 50 V ceramic capacitor (L13C9 - L14C9)● C5 - 100 nF, 50 V ceramic capacitor (L9C15 - L11C15)

Crystal (XTAL)The Crystal doesn’t have polarity. Solder carefully according to the image.

Components:● XTAL - 16 MHz crystal oscillator (L14C8 - L15C8)

SPST switch (S1)To solder this component you should straighten the pins so it fits in a 3 x 3 space. Solder carefully according to the image.

Components:● S1 - SPST normally-open type switch (L11C14 -

L13C12)

Male Head Pins (J1, J2, J3, J4, J5, J6, J7)

These should be soldered carefully. Solder only one pin at the beginning so its easier to straighten the head, then solder the rest.Solder carefully according to the image.

● J1 - 14-pin male header (L6C1-L19C1)● J2 - 8-pin male header (L6C10-L13C10)● J3 - 4-pin male header (L16C10-L19C10)● J4 - 6-pin male header (L4C16-L9C16)● J5+J6 - 5-pin male header* (L1C1-L5C1)● J7 - 2-pin male header (L2C6-L3C6)

* - Remove 2 of the pins

LED (LED1)The LED has a longer leg (+) which should be placed on the upper side, the smaller leg (-) should be on the bottom side. Solder according to the image.

Components:● LED - LED (3mm) (L3C2+ - L4C2-)

Electrolytic Capacitors (C1, C2)The C1 should have the (-) side up and the (+) side down. The minus is normally identified by a white strip and shorter leg.The C2 should have the (-) side down and the (+) side up. Solder according to the image.

Components:● C1 - 100 μF 25 V electrolytic capacitor (L2C13- -

L2C13+)● C2 - 100 μF 25 V electrolytic capacitor (L1C8+ - L2C8-)

7805 (U2)The metal side should be facing right and letters on the chip should be facing left. Solder according to the image.

Components:● U2 - 7805 linear voltage regulator (L1C10-L3C10)

ATmega328P (U1)Then, after finishing you can put the ATmega328P on the socket according to the image.

Components:● U1 - ATmega328P-PU microcontroller

Fully assembled board

Testing and using it

Make sure you don’t have shorts between tracksUse a USB/FTDI Breakout boardDisconnect the external power to the board when using the USB/FTDI programming breakout card.

Running a Test Sketch

Setup Arduino IDE:● Choose Arduino Duemilanove w/ ATmega328● Load Examples -> 01. Basics -> Blink

Demo

● Traffic Signals● MegaDemo● Ultrasonic Sensors

Q & A ?

Questions ?

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