Page 33 - Black Range Naturalist, Vol. 3, No. 1

Low-Cost Sensor Systems
A few years ago I was able to interview Harley Shaw about his research career. For me, one aspect of that career was especially intriguing. Harley was on the ground floor of the development of radio telemetry tracking systems. I suspect that he did not thoroughly understand the complete research implications of those systems at that time, that he might not have foreseen tracking terns for tens of thousands of miles,
To state that a system utilizes off-the-shelf components is easy, the concept is clean. But like most things which are clean and obvious they can be very difficult to accomplish. The devil, after all, is in the details, or in this case in wires, boards, and components made by different manufactures with differing capabilities and technical specifications (some of which appear to have been written by marketing departments).
following the migration of whales, or the exactness of GPS, for instance.
Recently I have been able to watch the development of a low-cost sensory system which may shape basic research, public safety policy, and the economics of extraction industries significantly. Or not, that is the beauty of the ground floor, you never know.
The state of current technology allows a significant amount of research in the field of geology to be conducted by remote sensors. But the full potential of that technology has never been realized, primarily because of cost.
The sensitivity of the array system is shown in these results from one of Barnes’ field tests. The sensors were recording the same event but were affected differently based on their location. Thus, subtle differences in land movement can be identified, not only the time (left column) at which each sensor recorded movement but what the rate of slip was (right column) for each sensor. Such nuanced results create a much richer analysis.
Each of the attributes of this system comes with assorted pros/cons. Using off-the-shelf components drives the system cost down to a fraction of the cost of other sensor systems. Although it is difficult to find reasonable comparisons, the Raspberry Shake 1D, which measures the magnitude of local seismic activity, costs from $374 to $499 per sensor. The RS 1D is not a comparable unit to one of the sensors of the subject system (see left); for one thing the RS1D sensor is much more sensitive. But it is one unit, built for one purpose. In another cost comparison, sensors in soil moisture systems regularly cost $200. In general, the cost of the Earth Movement Measurement System (EMMS) which Barnes has
For the last few
months, Jon Barnes
has been in the Black
Range working out the mechanical, electronic, and data handling kinks of a sensory system which is able to use off- the-shelf components. The system is inexpensive, robust, inherently scalable, supportive of a variety of redundancy schemes, and easily manipulated and supported in the field. Such a system could change a lot of things in research (geology is his field of choice), public safety, and infrastructure economics.
developed is projected to be roughly a tenth of the cost of existing systems with comparable capabilities. But off-the- shelf means the components are often general-purpose rather than purpose built. Determining what units are compatible turns out to be a significant task.
Marketing claims aside, components do not always work together. It is not always apparent why that is the case. For
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