Design and construction of a low-cost vibration sensor using electromagnetic induction.
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Date
2026
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Busitema University
Abstract
Vibration monitoring is essential for keeping machines running safely, detecting intruders, and warning people about earthquakes, but most commercial sensors are too expensive for ordinary households, small workshops, and schools in developing countries like Uganda. This study therefore aimed to design and build the simplest possible vibration sensor using electromagnetic induction, with just seven components: a 2.0 H inductor to pick up vibrations, a single BC547 transistor to amplify the signal, two resistors (100 ๐๐บ ๐๐๐ 10 ๐๐บ) for biasing and current limiting, an LED and buzzer for alerts, and a 9 V battery for power. When the inductor vibrates, it generates a tiny voltage through Faraday's law of induction, and this voltage drives the transistor base, switching on the LED and buzzer. Testing showed that the circuit draws only 0.6 ยตA when idle, meaning a battery could last for years, and it achieved 100% success in detecting vigorous shaking, 80% success for strong taps, and 40% for moderate taps, though very light vibrations did not trigger the alarm. All measured currents stayed well within safe limits for the components, confirming that the design is both functional and reliable. In conclusion, this study proves that a practical vibration sensor can be built with an absolute minimum of parts, making it an affordable and accessible tool for educational demonstrations, basic security applications, and simple machine monitoring in resource-limited environments.
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Undergraduate research report
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Citation
Wekhola, D. (2026). Design and construction of a low-cost vibration sensor using electromagnetic induction. [Unpublished undergraduate research report]. Busitema University.