A Complete Guide to Robotics for Middle and High School Educators
Introduction
Robotics is about more than just human-looking robots. A Roomba is a robotic vacuum cleaner and it looks nothing like a human or a vacuum cleaner. Robots can operate on their own like a Roomba, but there are also remote-controlled robot that require some human interaction. Drones are an example of a remote-controlled robot. There are robots that just perform repetitive tasks. like assembly-line robots. There are big robots that put fenders on cars and tiny robot that can be injected into the bloodstream.
Robotics is a big area but all robots have the same three basic elements that make them robots: circuits, sensors, and action. Here’s a description of each of these:
Sensors are fundamental to programming robotics. They are used to recognize environmental data (things like temperature, light levels, and motion) and provide the information they collect to computer code. If the computer code is looking for that information, it will use it to perform an action (like move something, light something, or communicate with a device or human).
This article describes the types of sensors that are common to robotics and teaching programming.
Sensors
Movement and Position
This category includes speed, acceleration, angle, and direction. Motion can be forward, backward, side-to-side, or up and down. Direction and position are determined using magnetic fields. Determining position may also require using vision capabilities to sense nearby objects and features to compare to a map.
Sensors in this category include:
Accelerometer
Accelerometers can recognize angle or tilt, up and down movement, and side to side movement. They are use to identify motion of the accelerometer itself and whatever it is attached.
Magnetometer
A magnetometer uses magnetic fields to determine direction. A compass is a type of magnetometer.
Light and Vision
Vision sensors are used for navigating, recognizing objects, sensing light levels and determining range and proximity.
Light sensors can be used to measure motion in another object
Types of light sensors include:
Photodiode
Photodiodes are devices that change their level of electrical resistance depending on the light level. The amount of resistance identifies the level of light.
LED
LEDs can be used to sense light levels in a manner similar to photodiodes. They are less sensitive than photodiodes but are also less expensive.
Ambient Light Sensor
Ambient light sensors are photodetectors that identify the ambient light level. They are used on devices like smartphones automotive display panels to adjust brightness according to the amount of ambient light.
Touch and Pressure
These sensors detect touch and pressure along with force and torque. Force is the amount of effort it takes to move something in a straight line, while torque is the amount of pressure it takes to rotate an object.
Capacitive Touch Sensors
Capacitive touch uses the electrical capacity of the human body to identify where a touch occurs on a screen. When a finger or other conductive material touches the screen’s surface, it disrupts the electric field at that point, which identifies the user’s selection.
It is the technology most commonly used in consumer electronics like tablets, smartphones, and gaming devices.
It has a high degree of accuracy, so it is good for smaller devices or applications where the touch area to select is small.
It can sense multiple simultaneous touch points, which are used for making multiple selections at once or for navigation. An example is when two points are touched and then pinched together to make the image smaller.
Resistive Touch Sensors
Resistive touchscreens have two layers with a gap between them, with the top layer being semi-flexible. Each layer has an electric grid and a resistive coating on the surface, preventing the two grids from making an electrical connection until pressure is applied to the top layer. When something presses the top layer, the electrical circuit is closed, identifying the location of the user’s selection.
Resistive touchscreens can work with devices that aren’t conductive and are more reliable in conditions where debris or fluids might get on their surface.
They are less expensive than capacitive touchscreens, which makes them popular in rugged or high-use settings. You see resistive touch used most often for factory automation, devices in construction, medical equipment, and in-flight entertainment stations.
Temperature and Humidity
Temperature sensors measure their temperature and the temperature of the air around them. This can be useful in industrial settings where materials need to be at a specific temperature for processing.
Sensing the temperature of an object is also useful to determine if something is overheating.
Humidity sensors can be used to determine moisture levels in homes or in agricultural settings.
Types of temperature and humidity sensors include:
Resistance Temperature Detector
The resistance level of a Resistance Temperature Detector (RTD) changes according to its temperature. The connection between resistance and temperature depends on the type of metal that is used to make the RTD.
These temperature sensors have a limited temperature range but they are compact and durable.
Pinless Moisture Meter
This type of moisture meter uses the conductivity of moisture to determine the moisture level.
Sound
Sound sensors use vibration to determine the sound level.
Microphone
A microphone is a sensor that can recognize sound waves, determine their level, and transfer that information in the form of a recording or data that it passes to computer code for processing.
Action
The action is the robot’s response to input from the sensors. Some robots move around in response. They may turn to avoid a wall, reach an arm to get a box with a particular barcode, or steer through someone’s blood vessels looking for signs of infection. Not all actions are physical motions though. Robots may also do things like set off an alarm, light up a room, or send a text message.
Circuits
Circuits provide the link between the sensors and the actions. Circuits need electricity to operate. They can be simple, like one that runs a light. Lights just have a connection to the power source (battery or electrical outlet), a light bulb or LED, and an on/off switch. Robots require a more complex circuit so they can receive information from sensors and assign actions to other parts of the robot. The part of the robotic circuit that does all of this work is called the controller, or microcontroller, and is the brains of the robot. People create the ability for the controller to work by writing computer programs and loading them into the controller’s memory. When the circuit is on, the controller uses the computer code to do its work