A breadboard is a construction base for prototyping of electronics. It
is used to build and test circuits quickly before finalizing any circuit
design. And it has many holes into which components like ICs and
resistors as well as jumper wires mentioned above can be inserted. The
breadboard allows you to easily plug in and remove components.
This is the internal structure of a full+ breadboard. Although there are
holes on the breadboard, internally some of them are connected with
Resistor is an electronic element that can limit the branch current. A
fixed resistor is one whose resistance cannot be changed, when that of a
potentiometer or variable resistor can be adjusted.
The resistors in this kit are fixed ones. It is essential in the circuit
to protect the connected components. The following pictures show a real
220Ω resistor and two generally used circuit symbols for resistor. Ω is
the unit of resistance and the larger includes KΩ, MΩ, etc. Their
relationship can be shown as follows: 1 MΩ=1000 KΩ, 1 KΩ = 1000 Ω, which
means 1 MΩ = 1000,000 Ω = 10^6 Ω. Normally, the resistance is marked on
it. So if you see these symbols in a circuit, it stands for a resistor.
The resistance can be marked directly, in color code, and by character.
The resistors offered in this kit are marked by different colors.
Namely, the bands on the resistor indicate the resistance.
When using a resistor, we need to know its resistance first. Here are
two methods: you can observe the bands on the resistor, or use a
multimeter to measure the resistance. You are recommended to use the
first method as it is more convenient and faster. If you are not sure
about the value, use the multimeter.
As shown in the card, each color stands for a number.
Semiconductor light-emitting diode is a type of component which can turn
electric energy into light energy via PN junctions. By wavelength, it
can be categorized into laser diode, infrared light-emitting diode and
visible light-emitting diode which is usually known as light-emitting
Diode has unidirectional conductivity, so the current flow will be as
the arrow indicates in figure circuit symbol. You can only provide the
anode with a positive power and the cathode with a negative. Thus the
LED will light up.
An LED has two pins. The longer one is the anode, and shorter one, the
cathode. Pay attention not to connect them inversely. There is fixed
forward voltage drop in the LED, so it cannot be connected with the
circuit directly because the supply voltage can outweigh this drop and
cause the LED to be burnt. The forward voltage of the red, yellow, and
green LED is 1.8 V and that of the white one is 2.6 V. Most LEDs can
withstand a maximum current of 20 mA, so we need to connect a current
limiting resistor in series.
The formula of the resistance value is as follows:
R = (Vsupply – VD)/I
R stands for the resistance value of the current limiting resistor,
Vsupply for voltage supply, VD for voltage drop and I for the working
current of the LED.
If we provide 5 voltage for the red LED, the minimum resistance of the
current limiting resistor should be: (5V-1.8v)/20mA = 160Ω. Therefore,
you need a 160Ω or larger resistor to protect the LED. You are
recommended to use the 220Ω resistor offered in the kit.
Wires that connect two terminals are called jumper wires. There are
various kinds of jumper wires. Here we focus on those used in
breadboard. Among others, they are used to transfer electrical signals
from anywhere on the breadboard to the input/output pins of a
Jump wires are fitted by inserting their “end connectors” into the slots
provided in the breadboard, beneath whose surface there are a few sets
of parallel plates that connect the slots in groups of rows or columns
depending on the area. The “end connectors” are inserted into the
breadboard, without soldering, in the particular slots that need to be
connected in the specific prototype.
There are three types of jumper wire: Female-to-Female, Male-to-Male,
More than one type of them may be used in a project. The color of the
jump wires is different but it doesn’t mean their function is different
accordingly; it’s just designed so to better identify the connection
between each circuit.
Connect one end of the 220ohm resistor to pin 9 of the Uno and the other
end to the anode (the long pin) of the LED, and the cathode (the short
pin) of the LED to GND. When the pin 9 outputs high level, the current
gets through the current limiting resistor to the anode of the LED. And
since the cathode of the LED is connected to GND, the LED will light up.
When pin 9 outputs low level, the LED goes out.
The schematic diagram:
Step 1: Build the circuit (the pin with a curve is the anode of the
Then plug the board into the computer with a 5V USB cable.
Step 2: Open the Lesson_1_Blinking_LED.ino code file in the path of
Step 3: Select the Board and Port
Before uploading the code, you need to select the Board and
Port. Click Tools ->Board and select Arduino/Genuino
Then select Tools ->Port. Your port should be different from
Step 4: Upload the sketch to the Uno board.
Click the Upload icon to upload the code to the control board.
If “Done uploading” appears at the bottom of the window, it means the
sketch has been successfully uploaded.
You should now see the LED blinking.
Code Analysis 1-1 Define variables
const int ledPin = 9; // the number of the LED pin
You should define every variable before using in case of making
mistakes. This line defines a constant variable ledPin for the pin 9.
In the following code, ledPin stands for pin 9. You can also directly
use pin 9 instead.
Code Analysis 1-2 setup() function
A typical Arduino program consists of two subprograms: setup() for
initialization and loop() which contains the main body of the program.
The setup() function is usually used to initialize the digital pins
and set them as input or output as well as the baud rate of the serial
The loop() function contains what the MCU will run circularly. It will
not stop unless something happens like power outages.
pinMode(ledPin,OUTPUT); // initialize the digital pin as an output
The setup() function here sets the ledPin as OUTPUT.
pinMode(Pin): Configures the specified pin to behave either as an
input or an output.
The void before the setup means that this function will not return a
value. Even when no pins need to be initialized, you still need this
function. Otherwise there will be errors in compiling.
Code Analysis 1-3 loop function
digitalWrite(ledPin,HIGH); // turn the LED on
delay(500); // wait for half a second
digitalWrite(ledPin,LOW); // turn the LED off
delay(500); // wait for half a second
This program is to set ledPin as HIGH to turn on the LED, with a delay
of 500ms. Set ledPin as LOW to turn the LED off and also delay 500ms.
The MCU will run this program repeatedly and you will see that the LED
brightens for 500ms and then dims for 500ms. This on/off alternation
will not stop until the control board runs out of energy.
a HIGH or
a LOW value to a
digital pin. When this pin has been set as output in pinModel(), its
voltage will be set to the corresponding value: 5V (or 3.3V on 3.3V
boards) for HIGH, 0V (ground) for LOW.