Electronics prototype · Completed

Room temperature monitor

A compact Arduino temperature monitor with a display, threshold alerts, and an enclosed electronics assembly.

Boston University · EK131 · Spring 2025

Enclosed Arduino temperature monitor displaying Celsius and Fahrenheit — Working prototype displaying a reading above the configured alert range.

Objective

I built and programmed an Arduino Uno temperature monitor with a TMP36 sensor, 16×2 LCD, red and green LEDs, and a buzzer. It displays Celsius and Fahrenheit and alerts the user when the temperature moves outside 60–75°F.

I wrote the firmware, assembled the circuit, arranged the components inside an ABS enclosure, and documented the build in a technical report.

Build

I used Arduino header connections and shared power and ground rails so the components could be reused. I arranged the display, sensor, switch, and alerts around a compact ABS enclosure and documented the LED resistor selection in the report.

Open enclosure showing the Arduino Uno, LCD wiring, battery, and sensor connections — Inside the prototype enclosure. Better wire routing and connector retention would be priorities in a second build.

Test / Results

Power: The circuit drew 76 mA. A 690 mAh battery gives an ideal estimate of about nine hours, though the Arduino would shut down before the battery was fully discharged.
Accuracy: The TMP36 datasheet lists ±1°C accuracy at 25°C. I did not calibrate the assembled monitor against a reference thermometer.
Next test: Measure runtime to shutdown, compare readings with a reference thermometer, and check whether the enclosure affects the sensor reading.

Wiring diagram showing Arduino Uno, TMP36, LCD, LEDs, buzzer, and battery — Wiring diagram from my report, showing the sensing and alert circuits.

Read the technical report (PDF).

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