Welcome to the RoboGames 2017 Electronics lesson. In this lesson, we will focus on the two sensors included in your Official mBot kit, the Line Following sensor and the Ultrasonic Distance sensor. To control your robot manually, you will need to use the IR Remote Control.
Infrared Remote Control (Manual Controller)
This video is a introduction to how to use How to use 2.4GHz wireless module and Bluetooth module with mBot.
This video is about teaching you how to establish communication between the graphical programming tool mBlock and the Robot mBot.
Line Following Sensor
In your Official mBot kit, your robot comes equipped with a Line Following sensor. This input sensor can sense the contrast between light and dark surfaces. Your kit comes with a large paper track that can be unfolded and placed on the floor. You can also make your own custom tracks to guide your robot. You can use a Sharpie on a whiteboard, or black electrical tape to make thick black lines that your robot will be able to follow.
The line following sensor is composed of two components, an output and and input:
Infrared LED (aka IR LED) – the output
Photo Diode – the input
As the above diagrams show, the IR LED emits infrared light. When the light energy reflects off a surface, the Photo Diode registers the amount of light that is being transmitted back. Since light colored surfaces will reflect more light, the robot can compare the light levels and identify when the black line is under the sensor. When there is less light reflected back, the robot can adjust it’s course depending on which sensor is seeing the variation in light levels.
When the Line Following sensors are both over light colored areas, the robot will move forward.
When the Line Following sensor on the LEFT is over a dark surface, the robot to turn left until it senses the light colored surface again.
When the Line Following sensor on the RIGHT is over a dark surface, it will turn right.
To test the Line Following sensor, you can use the IR Remote control on mode C, which will make the LED lights on your mBot turn BLUE.
The Official mBot kit includes an Ultrasonic distance sensor. This input sensor can measure distance to avoid obstacles. The robot can sense from about 3cm to 400cm pretty accurately. Using logic in your programming, this will act as the “eyes” of your robot to navigate the obstacle course or keep it’s distance from other robots. The Ultrasonic Sensor sends out a high-frequency sound pulse and then times how long it takes for the echo of the sound to reflect back. The sensor has 2 openings on its front. One opening transmits ultrasonic waves, (like a tiny speaker), the other receives them, (like a tiny microphone). The ultrasonic sensor measures distance. One of the “eyes” transmits a sound, and the other waits for the echo of the sound to return. From the time this process takes, the distance of the object from the sensor can be calculated.
The Ultrasonic Distance sensor is composed of two components, an output and and input:
Want to use more sensors? You will want to check out this resource which covers many additional options.
Wiring has always been a pain for DIYers. Normally you need to find a single pin from the sea of inputs/outputs repeatedly while worrying about loose cables and potential harm to your hardware/yourself from short circuits. Fortunately, this situation does not exist in the world of Makeblock.
Introducing RJ25 Wiring System – it is a simple method to connect your electronic modules with your controller board. Even a child can correctly match the colors of the sockets and build their circuitry of sensors; besides, RJ25 cables and connectors are sturdy, excelling in large robotic projects or classroom teaching.