Course Content
The Arduino UNO
In the following three lessons, you will get to know your microcontroller - the Arduino UNO. You will learn more about its history, its functions, and most importantly: how to power it.
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Overview
Power Supply
The Arduino UNO Rev4
The Arduino IDE
For beginners, the Arduino IDE (Integrated Development Environment) is usually the first choice – and for good reason. You can program all Arduino boards with it and manage libraries for sensors, displays, etc. It also features the "Serial Monitor," where you can output data and troubleshoot.
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Installation
Get to Know the IDE
Your first sketch
In the following lessons, you'll get to know the basic structure of an Arduino sketch and write your own programs. Let's get started!
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Setup and Loop
Make the LED on your Arduino Blink
The Serial Monitor
Now let's turn our attention to the Serial Monitor – a feature of the Arduino IDE that you will use in virtually every one of your projects.
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Overview
Hello, World!
Variables
No programmer can avoid variables. In the following lessons, you'll learn what types there are and what you can do with them.
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What are variables good for?
What Types Are There?
Variables in Action
Controlling an LED
Now it's time for more hardware! In the next lessons, you'll connect an LED to your Arduino. You'll first turn it on and off with a button. After that, you'll build a dimmer to control the brightness of the LED.
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How to Connect an LED
The Prototyping Shield
Controlling the LED with a Sketch
Conditional Statements, Comparison Operators & Modulo
Connecting a Potentiometer
Controlling the LED’s Brightness
Lie Detector
Discover the entertaining side of electronics by building your own simple lie detector with your Arduino. This fun project uses basic components to measure skin resistance changes when someone might be telling a fib, perfect for adding some playful suspense to your next gathering with friends.
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How to build this project
There’s music inside!
Your Arduino can do much more than "just" make LEDs shine at different brightness levels. For example, it can make music. In the following lesson, you'll learn how to use a piezo buzzer and coax some charming tones out of it.
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Connecting a passive piezo
Your First Arduino Instrument
A Music Box with Loops
A Theremin with Ultrasound
Do you want to make a bit more music? In this lesson, you'll build a theremin that you operate with your HC-SR04 ultrasonic sensor. You move your hand toward and away from the sensor - your Arduino calculates the pitch of the tones from the distance, which are then played through your piezo buzzer.
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Connecting the HC-SR04
Measuring Distances
Setup of the Theremin and the Sketch
Arrays
A Fixed Scale for the Theremin
The Sound Sensor
Ready to explore how your Arduino can respond to sounds? In this lesson, we'll connect a sound sensor to your Arduino and learn how to make it respond to both digital noise detection and analog volume levels.
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Using the Sound Sensor
Build an Alarm System
In this project, you will build your own alarm system. It consists of three components: the sound sensor, which you have just learned about, the active piezo buzzer, and the RGB LED.
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Connecting the active piezo and the RGB LED
The Sketch for the Alarm System
The DHT11 Temperature Sensor
Let's move on to another component that you'll certainly use in many projects: the temperature sensor. In this case, the popular DHT11, which can measure not only temperature but also humidity.
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Connecting the DHT11
Installing and Using Libraries
Measuring Temperature & Humidity
Arduino Course for Beginners

Not quite sure if someone is telling you the truth? Then it’s time for your own small lie detector. Your test subject only needs to hold two wires in their hands and answer your questions – and you’ll know whether they’re lying or not.

With this project, you won’t really find out if you’re being lied to. After all, even “professional” lie detectors aren’t capable of reliably bringing the truth to light. But it’s certainly enough for a bit of fun among friends! 🙂

How the Lie Detector Works

This project isn’t complicated: You connect three colored LEDs to the Arduino, which show you how far away from the “truth” an answer is. Another circuit is completed when your test subject holds two wires in their hands. You connect one of these wires to 5V. The other actually consists of two wires with a 10kΩ resistor between them, which you connect to GND.

This resistor is a so-called pull-down resistor that “pulls down” the measurement value at pin A0 to zero. If you didn’t use a resistor here, the measurements would “act crazy” – you would receive all kinds of values. You can check what this looks like by temporarily removing the resistor.

Depending on how much the person sweats on their fingers, their skin resistance decreases. You can measure these small differences and track them in your Serial Monitor. Let’s assume the test subject starts sweating when lying: The skin resistance decreases and becomes more conductive – the measurement value changes and increases. If the fingers stay dry, the flowing current encounters greater resistance – and the measurement value remains low.

___STEADY_PAYWALL___

The Setup

Use the following diagram as a guide for setting up your lie detector:

 

You can find the sketch for your lie detector in the Exercise Files for this lesson. There’s hardly anything to say about the sketch itself; you should already be familiar with all the commands. 🙂

Upload it to your Arduino and open the Serial Monitor. You should now see a zero running through it. This is the value being measured at analog pin A0. If you press the ends of the two detector wires together, you should see the value 1023, which drops again as soon as you separate the wires. If the value doesn’t return to zero, restart your Arduino with the reset button.

Now take one wire each between the thumb and index finger of your hands. Does the value increase slightly? Moisten your fingers and observe what happens then. One final note: Please keep in mind that this lie detector is a simple setup that won’t provide you with reliable values.

Exercise Files
lie_detector.zip
Size: 1.29 KB
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