Sensor-based Remote Temperature and Humidity Monitoring Device Embedded in Wheelchair Cushion

Increases in skin temperature and accumulation of moisture during prolonged sitting are risk factors for pressure ulcers. Therefore, a method of assessing temperature and moisture between the body and support surfaces is needed. The purpose of this study was to develop and evaluate a prototype for a wheelchair cushion equipped with remotely operated sensors to enable realtime monitoring of temperature and humidity by the wheelchair user. Twenty-six wheelchairbound patients gave informed consent to participate in this study. Participants were randomly assigned to sit naturally on either a hybrid foam-fluid cushion or an air-filled rubber cushion. During 2 h of sitting, a digital sensor was used to obtain bilateral temperature and humidity measurements at the ischial tuberosities and thighs. Temperature and humidity data collected by the sensors were processed with an Arduino Uno microcontroller. A Zigbee transceiver module mounted on the carrier board also enabled wireless transmission of the data to monitor the workstation. Experiments showed that this wireless, remotely operated monitoring system accurately detected changes in skin temperature and humidity, which were calculated as described in the literature. These vital signs could then be transmitted wirelessly to an online database for future access by other caregivers. The proposed device is a useful precautionary measure for ensuring the adequate monitoring of patients required to sit in wheelchairs for prolonged periods.