Design of a System to Monitor Youth Workers’ Heat Stress and Positioning Using Non-Invasive Techniques

Due to inadequate training and an undeveloped ability to recognize dangerous scenarios, youth workers can be exposed to many dangers in the agriculture and lawn care industries. With the abundance of new technologies available on the market, a project was devised to reduce the risk that youth experience heat exhaustion and equipment run-overs by employing sensor based technologies. Using aural temperature measurement techniques involving a thermistor and thermopile, an accurate estimation of core body temperature was demonstrated. The measurements performed by the devices are recorded and transmitted wirelessly over a ZigBee network using XBee radiofrequency modules. Utilizing the properties of wireless transmission, the Received Signal Strength Indication (RSSI) is used to approximate the distance between devices. With accuracy comparable to GPS methods and no necessity for line of sight to sky, RSSI supplies a more than adequate estimate for proximity distance. The temperature and RSSI values are then sent to a coordinating modem where the data is displayed for the supervisor. After testing and calibrating the device, it was found that these methods are effective for the monitoring of core body temperature and proximity of workers. The temperature sensor was able to measure temperatures with less than 0.25% error and the proximity sensor was able to estimate distance within 1.25 meters at close range.