Expanding Microcontroller Applications

This cheat sheet covers expanding microcontroller applications by building a light-sensitive lamp using a photoresistor and a thermometer system using a TMP36 temperature sensor, both with Arduino.

Core Principles

Microcontrollers can read analog signals from sensors.
Photoresistors (LDRs) change resistance based on light intensity.
TMP36 temperature sensors provide analog voltage output related to temperature.
Arduino's analog input pins (A0-A6) read signals between 0 and 1023.
Voltage dividers are used to create a measurable signal for microcontrollers.
Code can map sensor readings to control outputs like LED brightness or status.
Resistors have color bands indicating their resistance value and tolerance.
Block programming (like in Tinkercad) simplifies microcontroller coding.

Action Steps

Connect Arduino to PC via USB.
Build virtual circuits on Tinkercad, ensuring correct wiring.
Add/remove components in Tinkercad.
Connect components to Arduino using correct pins.
Develop simple block programs for simulation.
Understand the difference between analog and digital input signals.
Use LEDs, potentiometers, and pushbuttons.
Wire a photoresistor with a resistor to form a voltage divider.
Program Arduino to read the photoresistor and control an LED's brightness.
Swap photoresistor for a TMP36 temperature sensor.
Program Arduino to read temperature and control multiple LEDs based on thresholds.

Formulas

Analog Read Value: 0-1023
Temperature in Celsius (TMP36): (analog_read_value * 3.04 / 1000) - 40
Temperature in Fahrenheit: (celsius * 9/5) + 32

Key Terms

Microcontroller: A small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals.
Photoresistor (LDR): A light-dependent resistor whose resistance decreases with increasing incident light intensity.
Arduino: An open-source electronics platform based on easy-to-use hardware and software.
Tinkercad: A free, easy-to-use CAD design tool and 3D digital inventory for makers.
Analog Input: Input pins on a microcontroller that can read a continuously variable range of voltages.
Digital Input: Input pins on a microcontroller that read discrete states, typically HIGH (1) or LOW (0).
Voltage Divider: A simple circuit that divides a voltage into a smaller fraction, often used to interface sensors with microcontrollers.
TMP36: An analog temperature sensor that outputs a voltage proportional to the temperature.
Resistor Color Code: A system of colored bands on a resistor used to indicate its resistance value and tolerance.

Pro Tips

Always double-check wiring in Tinkercad before simulating.
Use the serial monitor to understand sensor readings and program behavior.
Map sensor values to a desired output range (e.g., 0-255 for LED brightness).
Ensure the TMP36 sensor is correctly identified; it looks similar to an NPN transistor.
Use comments in your code to explain different sections.

Pitfalls to Avoid

Incorrect wiring can lead to simulation errors or hardware damage.
Confusing analog and digital pins on the Arduino.
Misinterpreting resistor color codes.
Assuming a component is a temperature sensor when it's a transistor.
Not using a voltage divider circuit for analog sensors like photoresistors.

Real World Examples

Streetlights that turn on automatically at dusk.: Uses a photoresistor to detect low light levels and activate the light.
A digital thermometer displaying room temperature.: Uses a temperature sensor like the TMP36 connected to a microcontroller.
Smart home lighting that adjusts based on ambient light.: Combines light sensors with microcontrollers to control light intensity.

Timeline

Week 3a: Basic Arduino connection, Tinkercad circuits, analog vs. digital signals, LEDs, potentiometers, pushbuttons.
Week 3b (Part 1): Expanding applications: Light-Sensitive Lamp using Photoresistor.
Week 3b (Part 2 - implied): Expanding applications: Thermometer System using TMP36 sensor.

People

WIU (Western Illinois University): Institution providing the Engineering Exploration Project.

Quiz

What type of signal does an Arduino analog input pin read?: Analog
A photoresistor's resistance increases as light intensity...: Decreases
Which component outputs a voltage proportional to temperature?: TMP36 Temperature Sensor