Embedded Thermostat Controller

Embedded thermostat controller implemented in C using Code Composer Studio and TI Drivers.
The system reads temperature data from an I2C temperature sensor, compares it to a user-adjustable setpoint, and controls a heating indicator while reporting system status over UART.

This project demonstrates core embedded systems concepts including interrupts, timers, I2C communication, GPIO handling, and periodic task scheduling.

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Features

• I2C temperature sensor communication
• Adjustable thermostat set-point using hardware buttons
• Periodic temperature sampling using hardware timers
• UART serial output for system monitoring
• GPIO interrupt-driven user input
• Basic thermostat control logic

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Hardware Platform

• TI LaunchPad development board
• TMP temperature sensor (I2C)
• Onboard LED used as heater indicator
• Two push buttons used to adjust temperature set-point

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System Behavior

The firmware performs the following tasks:

1. Initializes system peripherals

   • UART
   • I2C
   • Timer
   • GPIO

2. Detects the connected temperature sensor over I2C

3. Starts a 1-second periodic timer

4. Every timer cycle:

   • Reads the temperature sensor
   • Compares temperature to the set-point
   • Activates the heater indicator LED if needed
   • Outputs system status over UART

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UART Output Format

The system periodically prints status messages via UART in the following format:

<currentTemperature,setPoint,heatOn,seconds>

Example:

<21,22,1,0045>

Meaning:

Field	Description
currentTemperature	Measured temperature (°C)
setPoint	Desired thermostat temperature
heatOn	Heater state (1 = ON, 0 = OFF)
seconds	System runtime counter

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Controls

Two push buttons adjust the thermostat set-point.

Button	Function
Button 0	Decrease temperature set-point
Button 1	Increase temperature set-point

Button presses trigger GPIO interrupts to modify the set-point.

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Software Architecture

The program uses a simple event-driven embedded architecture.

Timer Interrupt

A hardware timer generates a periodic callback every second.

timerCallback()

This callback sets a flag used by the main control loop.

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Main Control Loop

The main loop waits for the timer event and then executes the thermostat control logic.

while(1)
{
    wait for timer flag
    read temperature
    compare to set-point
    control heater LED
    send status over UART
}

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Peripheral Modules

Module	Purpose
GPIO	Button interrupts and LED control
I2C	Temperature sensor communication
UART	System monitoring output
Timer	Periodic scheduler

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System Architecture Overview

Buttons → GPIO Interrupts
            ↓
      Setpoint Control

Temperature Sensor → I2C → Thermostat Logic → Heater LED

Timer → Scheduler → Status Output → UART

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Key Embedded Concepts Demonstrated

• Interrupt-driven input handling
• Peripheral driver configuration
• I2C device communication
• Periodic scheduling using timers
• Embedded control logic
• UART debugging output

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Development Environment

• Code Composer Studio
• TI Drivers
• NoRTOS
• Embedded C

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Author

Michael Berry
B.S. Computer Science – Software Engineering