So, lets very briefly focus on the components I use in the basic examples from the very simple components to the more complex modules.



The above is an LED. The only thing important is that most LEDs you purchase online cannot run 5V, so you need to add a resistor if you want to keep the LED working. Also, you need to respect the minus and plus. Long leg means plus, short means minus.



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The resistor is in simple words used to lower the voltage for instance go from 5V to 4V if your component can only handle 4V.


LDR Resistor

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The LDR resistor is a light sensitive resistor that you can use to measure the level of light that the resistor receives. Its widely used to for example switch a lamp on when it gets dark outside.


9V Battery connector

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Not much to say, use this for connecting 9V to your prototype project.



Switches comes in many formats, I primarily use the one pictured below.

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This switch will be used to switch projects on and off or enable test-mode whenever needed.


Piezo buzzers

Buzzers are fairly simple components. They make a noise when you power them.

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The buzzer to the left is a normal buzzer that makes a quiet noise, the one to the right makes a lot more noise.


PCB boards

You can use PCB boards if you want to take your prototype project to the next level. Here you can add the components, wire them together and solder everything to make a prototype you can use “for real”.

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Laser Dot (5V)

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The laser dot is used in the example projects for making a simple tripwire. Respect plus and minus then you should be good.


MQ-3 Alcohol sensor


The MQ-3 is an analog sensor used in the Alcohol sensor project.


MQ-4 Gas sensor (Methane, etc.)

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This sensor is an analog sensor that senses the amount of gas and is used for the “Fart-o-sensor”.


PIR sensor


The PIR sensor is a motion sensor used for projects where you want an event when motion occurs.


DHT-22 Temperature and Barometric pressure sensor


A number of temperature sensors exists. The DHT-22 sensor measures both temperature and barometric pressure and is fairly accurate (~0.5 degree).


Moisture sensor


The moisture sensor is an analog sensor that measures the moisture level of for example a plant.


Ultrasonic sensor


The ultrasonic sensor measures the distance to any object and is again an analog sensor.

I use this for one of the alarm example projects.


RF 433Mhz RX and TX modules

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This is one of the affordable modules to use when you want something to work wireless. It’s not secure, nor long-distance, but it’s very cheap and work fine for prototypes. I use this for the snail-mail alarm example.


1602 LCD display modules


The LCD modules exists in a number of different versions here the 1602 module with 16 characters and 2 lines (eg. the name 1602).

The above image shows two versions, one on top where you need to solder wires to all of the 16 connectors and one on the bottom where an extra module have been added to make communication easier. I recommend the bottom one for beginners, but I have examples for both modules.


So, what’s next?

Now we’ll quickly look at the Multimeter that comes in handy especially when we are working with resistors… Hang on!