Temperature Monitoring & Alert System

Overview

This project implements a temperature monitoring and alert system using a LabJack DAQ, a temperature sensor, an LED, and a buzzer.
It was first prototyped on a breadboard, then designed into a custom PCB (schematic + layout in Fusion 360).
The repository includes the C program, schematic/board files, BOM, CAM outputs, and project images.

• Below threshold → LED stays on, buzzer off
• Above threshold → Buzzer activates (PWM on FIO4), LED turns off
• Exit strategies → Run for a set duration OR stop after a set number of buzzer activations
• Safe shutdown → LED and buzzer off, all pins reset before exit

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Program Description (C File)

PWM Setup

• Channel: FIO4
• Clock: 48 MHz / 47 divisor
• Mode: 8-bit timer
• Duty cycle: 50% (for buzzer control)

Startup

• LED initially off (DAC0 high).
• User enters temperature threshold (°C).
• User selects exit mode:
  • Run for a set time (seconds).
  • Run until a set number of buzzer activations.

Runtime Behavior

• Temperature read from AIN0 (voltage × 100 = °C).
• Below threshold:
  • LED on (DAC0 low).
  • Buzzer off.
  • Console prints current temperature.
• Above threshold:
  • LED off (DAC0 high).
  • Buzzer on (PWM).
  • Console prints “Temperature high” + temperature reading.

Exit Conditions

• Time-based: Program stops after specified duration.
• Activation-based: Counts buzzer activations until target reached.
• User may also choose to exit immediately at startup.

Shutdown

• LED and buzzer turned off.
• All pins reset.
• Program waits for user input before closing.

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Hardware & PCB Design

• Temperature sensor → AIN0 input.
• LED → DAC0 output.
• Buzzer → PWM on FIO4.
• Custom PCB created in Fusion 360:
  • Validated with ERC/DRC checks.
  • Fabricated and soldered components.
  • Tested with LJControlPanel.

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Images

Schematic Diagram

PCB Layout

Final Assembled System

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Design Files

• Schematic (.sch)
• PCB Layout (.brd)
• Bill of Materials (Excel)
• CAM/Gerber Outputs