Heating Up!: Wearable Device Designer

This project uses an Arduino to configure and code a prototype wearable device. To create a wearable temperature sensor, we first need to learn the basics of Arduino.

What is an Arduino?:

“Arduino is an open-source electronics platform based on easy-to-use hardware and software. It’s intended for anyone making interactive projects.” It is comprised primarily of two parts: a physical microcontroller (board) and computer-based IDE (integrated development environment).

Source: https://www.arduino.cc/

Using the Arduino: Power an LED

Divide students into pairs. Inform them that one student will serve as the “Electrical Engineer” the other will be the “Computer Engineer”. Throughout the lesson, these roles may interchange. Their first task as a team is to turn on an LED using a set of materials. They are also tasked with confirming their electrical configuration will power the LED using TinkerCAD Circuits.

Challenge: Use the Arduino to power an LED

Seeing Digital Information: Arduino Blink

Student’s next task as a team is to program an LED to blink. They should continue to configure the physical circuit with the Arduino and confirm the configuration with TinkerCAD Circuits.

Challenge: Program an LED to blink using the Arduino

Breakdown the Arduino Components & Code:

Explain how a (mini) breadboard functions: Rows of pins (holes) are connected by conductive metal strips and allow current to flow freely while remaining separate from adjacent pin columns.

Explain the LED and polarity: Polarity means current can only flow in one direction. The longer lead of the LED is the anode (+) and the shorter end is the cathode (-). Current flows from a source of higher potential energy to a source of lower potential energy. Connect “+” sources to the anode of the LED and “-” sources to the cathode of the LED.

Explain the Arduino code:

setup() function runs once and establishes features or “rules” of your code

pinMode(“pin, “mode”) establishes a pin and mode: modes can be OUTPUT or INPUT

loop() function runs indefinitely unless prompted to stop

digitalWrite(“pin”, “value”) sets pins to a value: HIGH for on, LOW for off

delay(“ms”) wait for a set amount of milliseconds

Comments (noted as “//”) notate the code within the file. Comments are not read by the computer but are instead helpful reminders about the code. In TinkerCAD, it’s “Notation”.

Revisit the previous Blink challenge and ask students the following questions:

• What does changing “1” in the delay or wait () secs argument to a different number do?
• How does changing HIGH and LOW affect the blinking?
• What happens if you change all instances of “LED_BUILTIN” to “13”? “1-12”?

Blink Revisited: Writing Code Yourselves

Open TinkerCAD Circuits and select the Code button to bring up the display pictured above. Use the dropdown menu to select Blocks + Text. Students can view the blocks and how it writes the real Arduino code by adding to the work plane. Both engineers will practice coding together.

Gathering Digital Information: DigitalReadSerial

Challenge: Read digital information from the Arduino by pressing a pushbutton switch.

Actuators and Sensors

The Arduino board is a microcontroller. These devices take in and send out information. More specifically, “microcontrollers listen to sensors and talk to actuators”. Students have now explored both an actuator (LED) and sensor (pushbutton switch). Additional examples of each are as follows:

Sensors: Temperature sensors, Accelerometer, Motion sensors

Actuators: Sound buzzer, Motor (servo motor), Piston

“Things that convert other forms of energy into electrical energy are often called sensors, and things that convert electrical energy into other forms of energy are sometimes called actuators.” (Source: Arduino)

Gathering Analog Information: AnalogReadSerial

Challenge: Read analog information from the Arduino by using a potentiometer.

Arduino Code Breakdown II:

Serial.begin(9600) – talk between computer and Arduino at the standard 9600 bits/second

digitalRead(“pin”) – inspects a digital pin

analogRead(“pin”) – inspects an analog pin

Serial.println() – prints data defined within the () on a new line in the Serial Monitor

Analog: information existing on infinite range, ex. numbers from 0 to infinity.

Digital: information existing on a limited range usually in two states, Ex. 0 to 1.

Arduino has a built-in Analog to Digital converter. In the previous challenge, it converted analog voltage information (0-5V with an infinite range of values in between) to a number 0-1023.

Potentiometers are essentially resistors. Twisting the knob varies the resistance by “changing the ratio of the voltage between the middle pin and power.” They are similar to light dimmers.

Combining Challenges: Analog Blink

Challenge: Program an LED to blink using input from a potentiometer

Introduce students to the final challenge by showing them the following video describing build and use of a temperature sensor for safely shoveling snow in cold weather:

https://www.youtube.com/watch?v=N9gW5cmOb78

Heatin’ Up: Temperature Sensor

Challenge: Construct a prototype wearable device that can track a player’s temperature data.

Temperature Sensor Redesign

Students can begin to redesign their temperature sensor by making it more of a wearable device. The following technologies could help improve these Arduino coded devices:

Modifying the Code

Changing lines of the code to read in new information and write or present different data could improve the overall experience with the device. One example might be to add several LEDs and create a light meter wherein more LEDs light up the greater the temperature.

Additional Electronics

The addition of extension wires, solder connections, header pin connecting cables, battery adaptors, and any other devices could increase the device’s portability, accessibility, and comfort.

Vinyl Cutting

Custom designed patches could apply the sensor of the device to the wearer’s skin or clothing. These could allow for the sensor to securely and accurately measure temperature while the wearer performs various activities. Additionally, it could also add to the aesthetics of the device.

3D Printing

Crafting a housing unit using CAD software (like TinkerCAD) to compactly store the Arduino while using the device protects both the wearer and the Arduino.