Automation of moisture level measurement in charcoal briquettes

¹ Sanata Dharma University, Electrical Engineering Department, 55281, Sleman, Indonesia
² Sanata Dharma University, Mechanical Engineering Department, 55281, Sleman, Indonesia

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

Charcoal briquettes, made from organic waste. Their quality depends significantly on moisture content, which affects electrical conductivity. This study focuses on automating moisture measurement using electrical resistance. The device employs a current-sensing circuit, an analog-to-digital converter, Hall effect sensors, and servo-driven clamps with plate-shaped electrodes to grip briquettes and measure resistance. Briquettes are fed into the system by a rotary feeder. Testing on batches of 10 briquettes classified as dry, half-dry, and wet showed classification success rates of 100% for either dry or wet conditions and 55.6% for half-dry conditions, despite occasional errors from resistance values outside predefined ranges. Resistance ranges recorded were 11.38–15.80 MΩ (dry), 3.37–7.59 MΩ (half-dry), and 0.02–0.80 MΩ (wet), corresponding to moisture contents of 0–3.03%, 7.27–11.52%, and 11.52–16.36%, respectively. The half-dry resistance values were closer to the wet range, indicating the half-dry batches were not distinctly intermediate between dry and wet. The rotary feeder showed practical reliability with 88% success for loading briquettes into chambers and 77.5% for positioning them on the measurement table, enabling effective automation. Overall, the system demonstrated the capability to measure moisture content and classify briquettes by dryness.