Design and Testing of a Microcontroller-Based Digital Weighing Scale for Market Traders in Kano State

Traditional mechanical weighing scales in Kano's markets are susceptible to calibration drift, deliberate tampering, and inability to display tare weights, contributing to unfair trade practices and economic loss for buyers. This project designed and tested a microcontroller-based digital weighing scale targeted at market traders in Kano State, North West Nigeria. A 50 kg load cell with HX711 analogue-to-digital converter was interfaced with an Arduino Nano microcontroller. A 16x2 LCD display presented weight readings in kilograms with a resolution of 0.01 kg. The system incorporated tare functionality, an auto-zero calibration routine, and unit conversion between kilograms and pounds. A buzzer alarm activated when the weight exceeded the 50 kg maximum. The scale was constructed within a steel housing with a stainless-steel weighing platform suitable for wet and dusty market environments. Ten calibration tests using certified reference weights ranging from 1 kg to 50 kg showed a maximum deviation of 0.03 kg. Repeatability error across 20 repeated measurements was 0.02 kg. Battery life on four AA alkaline cells was 14 hours of continuous use. Total material cost of the prototype was 9,200 naira, compared to approximately 85,000 naira for imported commercial digital scales of equivalent capacity. The study recommends adding a thermal printer for receipt generation and a local-language Hausa display option to improve usability for Kano State market traders, with possible involvement of the Kano State Bureau of Weights and Measures in certification.

Keywords: digital weighing scale, load cell, microcontroller, market trade, Kano State