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, demonstrating analogue input and output control.

Core Principles

Microcontrollers can read analogue signals from sensors.
Photoresistors (LDRs) vary resistance based on light intensity.
TMP36 temperature sensors provide analogue voltage output proportional to temperature.
Arduino's analogue inputs (A0-A6) read signals between 0 and 1023.
Voltage dividers are used to create a measurable signal for microcontrollers.
Block programming (like in Tinkercad) simplifies circuit simulation and code development.
Mapping sensor values to output ranges (e.g., LED brightness, LED states) is a common application.
Resistors are crucial components for controlling current and voltage in circuits.

Action Steps

Connect Arduino to PC via USB.
Create virtual circuits on Tinkercad, ensuring correct wiring.
Add/remove components in Tinkercad.
Correctly connect components using a breadboard.
Select appropriate Arduino pins for component connection.
Develop simple block programs and simulate circuits.
Understand the difference between analogue and digital input signals.
Build a light-sensitive lamp using a photoresistor, LED, and resistors.
Build a thermometer system using a TMP36 sensor and LEDs.
Map sensor readings to control output devices (e.g., LED brightness or state).

Formulas

Voltage Divider: $V_{out} = V_{in} \times \frac{R_2}{R_1 + R_2}$
Temperature Conversion (Celsius to Fahrenheit): $F = (C \times \frac{9}{5}) + 32$

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.
Analogue Input: An input pin on a microcontroller that can read a continuously variable signal, typically voltage.
Digital Input: An input pin that reads a signal as either HIGH (on) or LOW (off).
Breadboard: A construction base for prototyping electronics, used to build circuits without soldering.
Tinkercad: A free, easy-to-use, cloud-based 3D design and 3D printing application.
Voltage Divider: A simple circuit that divides a voltage into a smaller voltage, often used to interface sensors with microcontrollers.
TMP36: An analogue temperature sensor that outputs a voltage proportional to the temperature.
Resistor: An electronic component that resists the flow of electric current.

Pro Tips

Always double-check wiring in Tinkercad before simulating.
Use the serial monitor to understand sensor readings and debug code.
The `map()` function is essential for scaling sensor values to control outputs.
Ensure correct identification of components like transistors vs. sensors.
Consider using different resistor values to fine-tune circuit behaviour.

Pitfalls to Avoid

Incorrect wiring can lead to simulation errors or component damage.
Confusing analogue and digital pins on the Arduino.
Misinterpreting resistor colour codes, leading to incorrect resistance values.
Not using a voltage divider for sensors like photoresistors and temperature sensors.
Assuming components are identical when they are not (e.g., TMP36 vs. NPN transistor).

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 to measure ambient temperature and display it.
Smart home lighting that adjusts brightness based on ambient light.: Combines photoresistors with microcontrollers to control LED brightness.

Timeline

Week 3a: Basic Arduino connection, Tinkercad simulation, analogue vs. digital signals, use of LEDs, potentiometers, pushbuttons.
Week 3b (Part 1): Expanding applications: Building a light-sensitive lamp using a photoresistor.
Week 3b (Part 1): Learning to read photoresistor values and map them to LED output.
Week 3b (Part 1): Introduction to resistor colour codes and voltage dividers.
Week 3b (Part 1): Building a thermometer system using a TMP36 temperature sensor.
Week 3b (Part 1): Programming LED indicators for different temperature thresholds.

People

Arduino: Open-source electronics platform and microcontroller board.
TMP36: Specific model of analogue temperature sensor.