Internet of Things (IoT)-Based Smart Chamber for Respiration Rate Assessment of Fresh Capsicum

Authors: Majahar Ali and Pradeepta Kumar Sahoo

Book: Transforming Food Analysis and Control: Non-Destructive Technologies and Innovations

Editors: K. Prasad, S. Shekhar, M. K. Paswan, and R. Ahuja

Publisher: SLIET Longowal

Publication year: 2026

Publication date: 2026-07-20

ISBN: 978-81-990304-1-1 (e-book); 978-81-990304-0-4 (hardback)

Chapter pages: 251–266

DOI: To be added after DOI registration.

Abstract

An Internet of Things (IoT)–based airtight smart respiration chamber was developed to enable real-time measurement of the respiratory characteristics of fresh capsicum under ambient storage conditions. The system integrates Arduino Nano 33 IoT and ESP32 microcontroller platforms with a DHT22 temperature–humidity sensor, an electrochemical oxygen sensor (SEN0322), and an NDIR-based carbon dioxide sensor (SEN0220) to continuously monitor headspace O₂ and CO₂ concentrations, temperature, and relative humidity. Sensor data were wirelessly transmitted at 15 s intervals to the ThingSpeak cloud platform for real-time visualisation, storage, and analysis. Respiration rates were determined using mass balance equations based on measured rates of oxygen consumption and carbon dioxide evolution in the closed system. The results showed a decrease in O₂ concentration from 20.97% to 20.31% and a corresponding increase in CO₂ concentration from 0.0395% to 0.6732%, confirming active aerobic respiration. The calculated rates of O₂ consumption and CO₂ production were 19.575 mL kg⁻¹ h⁻¹ and 18.699 mL kg⁻¹ h⁻¹, respectively. The respiratory quotient (RQ) was found to be 0.96, indicating predominantly carbohydrate-based metabolism. Proper sensor calibration ensured high measurement accuracy and system stability. The developed IoT-based smart chamber demonstrated reliable performance in quantifying respiration dynamics of fresh capsicum and offers a low-cost, scalable, and efficient alternative to conventional laboratory-based respiration measurement techniques. This system provides a scientific basis for optimizing postharvest handling strategies and designing suitable modified atmosphere packaging (MAP) systems to reduce postharvest losses.

Keywords: Internet of Things (IoT); respiration rate; respiratory quotient (RQ); capsicum; smart chamber; postharvest management

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