Description
A sensor sleeve has been designed that allows the pressure applied by an orthopedic cast to be measured. A number of experiments were carried out to determine the most appropriate textile sensor for this application. Out of all the types of sensors tested, two layers of Velostat with a top and bottom layer of nylon had the least variability between sensors with a suitable resistance range. Individual sensors can be constructed separately and then sewn onto a spandex-nylon sleeve to ease the manufacturing process. The output of these sensors cannot be compared directly as they give an indication of the relative, not absolute, force being applied.
The original SmartCast sensor matrix contained a number of additional paths through the network which confounded the resistance measurements. In order to develop an appropriate solution, the sensor network in [15] was examined and compared to the sensor network used in SmartCast. While the analog interface used in [15] is different than that used in the SmartCast system, a similar solution was used in SmartCast to weaken the effect of the multiple paths, namely tying the unused rows to the 1V reference.
The SmartCast system firmware has been developed and verified . This code was used to obtain all the sensor measurement data presented in this thesis. Furthermore, the firmware has been designed to extend the system lifetime, namely by using the sleep mode of the microcontroller, cutting power to the external SDCard and by using the internal Flash and EEPROM memory of the microcontroller.
SmartCast Circuit Schematic
This code has a document (137 pages) which describe the algorithm in detail.
References
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Design a complete device with the initial interface for different sensors using Wolfram Mathematica
Kiaan –
Great work.