Estimating ram sperm concentration using an ESP32-based absorbance device: Design, calibration, and field application

¹ School of Veterinary Medicine and Biomedical Science IPB University, Bogor, Indonesia
² Department of Mechanical and Biosystem Engineering, Faculty of Agricultural Technology IPB University, Bogor, Indonesia
³ Paramedic Veterinary Study Program, IPB University, Bogor, Indonesia
⁴ Division of Reproduction and Obstetric, School of Veterinary and Biomedical Science IPB University, Bogor, Indonesia

^* Corresponding author: ulum@apps.ipb.ac.id

Abstract

Accurate and rapid evaluation of sperm concentration is critical for assessing ram fertility, particularly under field conditions where laboratory facilities are limited. This study aimed to develop and validate a compact, portable, and cost-effective device for estimating ram spermatozoa concentration using light absorbance based on the ESP32 microcontroller. The device employs a WS2812 LED as the light source and a BH1750 sensor to measure light transmittance through semen samples placed in an Eppendorf tube. Semen was collected using the artificial vagina method and analyzed manually using a Neubauer counting chamber and prototype device. Fifteen samples were used for calibration, resulting in a strong negative correlation between sperm concentration and light absorbance (R² = 0.9461). Field testing with 10 Garut rams demonstrated no statistically significant difference (p = 0.5816) between the ESP32-based device and standard counting method, confirming its accuracy. This device significantly reduces the time required for sperm analysis and is well-suited for field applications. Its small size (<1 kg), battery operation, and low production cost (<USD 100) make it a practical tool for rapid on-site semen quality assessment. The implementation of this technology has the potential to reduce human error and mitigate sperm quality degradation due to delayed analysis.