Adara Systems is a tiny company that designed, developed and maintained a wide variety of geotechnical and geophysical test tools. It's a daughter company to ConeTec, which is a geotechnical engineering company that used most of Adara's products. Glenn Jolly was the president of Adara and once I started working there in August of 1991, it was just Glenn and me. Ron Dolling joined us a few years later.
Glenn is a very multi-talented guy and a great mentor. I learned a lot from him about strain gauges, accelerometers, signal conditioning, embedded programming and mechanical design. From him I also learned a lot about developing products with almost no budget. About every six months we would roll out a new product for the customer with working prototypes, usually at a price of $50,000 or less.
Of course the profit margins (if any) were very low, the pay sucked and we never had adequate tools. However, my time at Adara was an excellent learning experience. This was also a time of unparalleled productivity. Our three-man company was able to deliver more working product per hour of effort than in any of my other jobs.
Adara Geotechnical Tools used by ConeTec
Glenn left Adara a few years after I did and soon afterwards, Adara was absorbed by ConeTec. Conetec's web site still has data sheets on the tools that Adara developed.
Cone Penetration Testing (CPT) was ConeTec's bread and butter. The Cone Penetrometer was very typical of Adara's products: a stainless steel spike loaded with sensors and signal conditioning electronics that is meant to be rammed up to 100m through water, mud, sand, clay, and soft rock.
I did most of the mechanical design and drafting for the cone and its accessories. I also built and repaired several dozen cones.
- Piezo Cone Penetrometer
- Seismic Cone Penetrometer
Piezometer Data Logger
The Piezometer Data Logger was used to monitor pore water pressures under building site preloads so that builders would know when it is safe to remove the preload and start putting up the building. This was the product where I had the most input into its creation:
- Mechanical design of down-hole sensor and data logger
- Design of down-hole sensor circuit board
- Design of data logger electronics
- Design of data logger firmware
- Specification of PC software
Adara Geophysical Tools
The most interesting work was developing geophysical testing tools for the Geophysical Survey of Canada and the Ocean Drilling Project. These were higher end, more application specific pieces of equipment that were most often used on the ocean bottom. Glenn designed and built microprocessor-based data logging systems that fit into the annular ring of a core sampler that was rammed into sediments on the ocean floor.
Deep Water Temperature Logger
One project that had us working long hours was a highly sensitive temperature logging device that was strapped to the outside of a core sampler and dropped into ocean sediments in the Marianas Trench, the deepest water in the world. I designed about half of the tool's firmware and most of the pressure housing. We built several of these tools. They didn't all survive but some did and recorded data from the deepest part of the ocean.
Differential Pressure Sensor
Slope failures are known to happen on the Fraser River delta. Since there are some important structures on the delta, including a ferry terminal, coal port and power cables, the GSC wanted to know what mechanisms trigger these slope failures. One possible mechanism was a difference in water pressure between the surface and deeper layers of sediment, either induced by storm waves or large tide exchanges.
Glenn and I developed a data acquisition system and two sensor heads to measure water pressure both at the sea floor and two metres below. We contracted out the software development. The sensor heads were installed in the shallow water off the Sandheads lighthouse near Steveston and the data logging equipment was safe inside the lighthouse itself. I got to use my diving skills for the deployment and recovery of the probes. I was also responsible for going out to the lighthouse to collect data.
This was an interesting lesson in how the ocean doesn't give up her secrets easily. The first probe was lost in an underwater slide before any data could be collected. Currents swept the sediment out from under the second probe over the course of one winter, invalidating much of the data collected.
RUMBLE stands for Remote Underwater Monitoring before Liquefaction Event. The GSC devised this project in the hope that they would lose another probe but this time capture the event on disk as a pressure and tilt signal. The RUMBLE project was a joint venture between Adara, ConeTec and the GSC. The GSC designed and built the data logger, Adara supplied the sensor heads, and ConeTec made the initial installation. I had the job of maintaining the site, collecting data and sending that data to the GSC.
The probes were installed at the outer edge of the Fraser River delta, over 1 km from the Sandheads lighthouse. The data logger was installed on the sea floor in a safer location, about 100m closer to shore. In the event of the anticipated slope failure, the probes would be lost but the data logger would remain intact.
The buoy we used to mark the location of the data logger was soon knocked off by a passing boat. The pinger meant to locate the data logger in case the buoy was lost also failed to operate. Therefore, the only way to recover the data and replace the batteries was to find the general neighbourhood using GPS and then conduct an underwater search. This was another chance to use my diving skills on the job but it was also physically exhausting work.
By the time the project wrapped up, no slope failure had occured but the frame that held the data logger was almost completely buried in sand.