Bryce Ott, Mike Coleman, Tyler Monson, Janell Armstrong, Ben Tanner, and Brad Anderson with Dr. Steven Renshaw, Information Technology
DynaSense is a robust and modular remote monitoring system that can be incorporated into an existing network. Individual embedded hardware modules gather and log data from attached sensors. This data is web-accessible from each individual module or can be compiled and monitored by custom management software for additional processing and display. A variety of industries could benefit from the features provided in the DynaSense system, including hospitals and clinical centers, manufacturing plants and refineries, museums, grocery stores, and the military.
The majority of monitoring systems presently available are single piece solutions. Each monitored location requires a separate instrument, and these instruments must be logged individually. The few options that do provide the capability of networking several instruments use a proprietary setup that cannot be easily integrated with others. The instrument connections and transfer rates are usually serial, thus making them slow and limited in distance.
Several features of the DynaSense system provide solutions to these issues. The DynaSense remote monitoring system:
1. Functions with one or many hardware modules
2. Provides the user with a dynamic device that will accept multiple sensor types.
3. Combines the measurements from all sensors in the network into a common interface.
4. Allows remote access to sensor readings via an Ethernet or wireless connection.
5. Provides comprehensive software to monitor and configure all networked modules.
6. Combines multiple sensor readings to create a modular sensor network.
7. Stores the sensor measurements within a relational database.
8. Buffers the measurement data within the sensor module in the event of connectivity loss.
9. Provides user authentication for the transfer and monitoring of measurement data.
The DynaSense project functionality and development was divided into three sections: physical layer (hardware), transport layer (device communication), and application layer (management software). This approach evenly distributed the workload and allowed team members to work in the area that most interested them or where they could make the most contribution. The remainder of this report will provide a brief overview of each section.
The hardware module began with a PC104 board. This TS-5500 provided an accessible, low cost alternative to other embedded systems considered. This board provided the necessary features including PC104 standard compliance, 802.11b wireless PCMCIA card, 64 Mb flash memory, analog inputs, analog to digital converter (ADC), and the ability to run an embedded Linux operating system. Interaction with the PC104 sensor module was done through a development PC running a full version of Linux.
Two sensors were developed for the DynaSense prototype: humidity and temperature.
The Thermometrics 5611 thermistor works well in the required range ((+/-25°C ) and sufficient accuracy (+/-1°C). Typically a thermistor is not linear as it moves up and down in temperature. This can be difficult to measure so it was decided to use a linearization resistor in parallel with the 5611. It was also necessary to limit the current to the microamp range to prevent self-heating in the thermistor. The Honeywell HIH3610 is a linear output voltage device that varies from 0 to 5 V DC over the humidity range 0 to 100% Rh. Assuming linearity, the humidity sensor should be able to measure within the required +/-3%Rh.
The transportation section of DynaSense facilitates the communication between the hardware modules and user including: sensor configuration, sensor data, and network connectivity. A simple web interface running on each hardware module allows users to view data and settings stored in XML files. Custom Java software modules also periodically download the XML data files from each hardware module and insert the data into the relational database for use of the management software. The management of the network settings allows the user to first install the management software, connect all hardware modules, and then quickly configure them through the management software. The hardware modules automatically select an available IP address which may later be reset by the user.
The relational database stores information about the DynaSense System. This MySQL platform maintains information on the network’s configuration and stores all data collected from the networked sensors. The database also contains information about user and administrator access rights, viewing preferences, and contact information. Alerts may be set through the DynaSense Management software to indicate the necessary action if predefined sensor reading thresholds are breached. As part of the management software, templates allow user customization in displaying data, providing software security, and changing webpage appearance.
The development of DynaSense provided all team members with valuable undergraduate research and development experience. The DynaSense project provided real-life product development from the design through implementation stages. In addition, the end result created a useful product that improves products and services many industries.