An introduction to the Arduino, delivered at Chalkwell House for a Southend Educational Trust organised Arduino Hack Day

1. ARDUINO

2. Open Source
Open Hardware
A simple computer which can gather input
from reality and interface outputs with the
environment however you instruct it to
http://arduinothedocumentary.org/

3. Fundamentals Of Arduino
• Write sketches or modify existing ones to
suit your needs
• Wire an electrics circuit
• Upload the sketches to the Arduino (via
USB connection) and connect the
electrics circuit to the arduino, by joining
wires to the sockets on the Arduino board

4. What is Arduino?
• 5V & GND : sources of power
• Inputs and Outputs
• Data transmission
Nomenclature
• On board sockets = Pins
• Any numbered pin = input
or output
• TX = transmitting
RX = receiving
• Arduino AKA microcontroller
fig (i)

5. Sources of Power
fig (ii)
●
The arduino has three GND pins and one 5V out
●
The pins can be used to create a 5v DC circuit,
_sufficient to illuminate an LED (fig ii, above)
●
A resistor is necessary to ensure the current does not
_burn out the LED

6. Breadboard: An Arduinos Companion
●
The breadboard holds components external to Arduino
●
Each socket on a breadboard connects to a conductive
_horizontal or vertical strip

7. Electrical Circuits
fig (iii)

The yellow trail indicates the positive pole of this circuit

The green trail indicates the common or negative pole

When both trails are linked by the LED, the circuit is
_completed

8. The Logic of Switches
fig (iv)

The LED does not complete the circuit this time –
_instead a button links the positive and negative poles
_of the circuit

A button can be pressed (ON) or not pressed (OFF)

Depending on the buttons state (ON/OFF) the circuit is
_complete or open

9. Input & Output: Digital
●
Digital Pin :: input & output
●
Digital means two possible
states
➢
HIGH/LOW = ON/OFF
➢
5v – 0v = ON/OFF
●
Programmed code tells the
arduino whether each pin is
HIGH/LOW (aka on/off)
(The arduino assumes a
pin to be off until told
otherwise)
fig (v)

10. Digital Switches
fig (vi)
●
This circuit is the same as fig (ii)
●
This time the HIGH signal from digital pin 13
_supplies the 5v positive pole to the circuit

11. Digital Sensors
Digital pins detect whether a
circuit is in an ON or OFF
state
When arduino measures
voltage in a circuit it will
register
0 – 2.5v equal to LOW
2.5v – 5v equal to HIGH
LOW == OFF
HIGH == ON
fig (vii)

12. Input & Output: Analog
* Analog Pin(s) :: input only
* Analog is different to digital
*Analog equals continuous
*Digital equals discreet
* Not just HIGH/LOW
* Instead 0 – 5v is a wider
spectrum of values to measure
0 – 5v = 0 – 1023 in Arduino fig (viii)

13. Multimeter: Good Electronics Practice
• Multimeter reads resistance,
voltage and ampage
• Multimeter is a big help to
making sure you’re
electronic circuit works the
way it should:
• a circuit should always work
the way you expect it before
writing/amending arduino
code

14. Other Variable Resistors
• LDR
= Light Dependant Resistor
• Thermistor
= heat dependant resistor
• GSR
= Galvanic Skin Response Galvanic Skin Response
• FSR
= Force sensitive resistor
Thermistor

15. Serial Port Communication
Serial Port is how the Arduino
Communicates with other Digital
Devices (E.G. the computer or a
digital SD card)
All computer tethered
communications go via the serial
port which arduino is connected to
Serial Port data can be accessed
by software other than Arduino
programming software (most
readily via Processing)
Arduino can save data to SD
cards using the TX and RX
facilities (advanced feature)