This workshop was a smorgasbord of dataloggers, filled with details about how they function, how the recorded information is moved from one device to another to be analyzed and repurposed, and how to think about choosing the right type of datalogger to match a particular environmental goal. I came into the workshop hoping to learn about new equipment that’s on the market now, to advance my institution’s upcoming project to re-invigorate our environmental monitoring and control program, in support of both energy and preservation goals. I got what I came for!
The workshop was taught by Samantha Alderson and Rachael Perkins Arenstein, both of whom have advised institutions large and small about environmental monitoring programs, and clearly know what they are talking about. They recently updated the National Park Service Conserve-O-Gram (“Comparing Temperature and Relative Humidity Dataloggers for Museum Monitoring,” September 2011, Number 3/3, http://www.nps.gov/museum/publications/conserveogram/03-03.pdf ), which is worth reviewing, but with the caveat that the technology is changing so rapidly that vendors and specifications should be researched anew when you’re planning for a major purchase.
The presenters started by reviewing basics of the hardware and connectivity, summarizing what kind of data loggers can collect, how many loggers one needs, and where to place them, and for how long. They also talked about general environmental management concepts so the less experienced in the audience wouldn’t be left behind.
They then explained a basic difference between two families of dataloggers:
- Stand-Alone Loggers collect data which is then harvested either by direct wired connection to a computer, through an indirect intermediary device like a card reader or thumb drive, or wirelessly; this method is appropriate when you don’t need real-time data
- Connected Loggers either wired (Ethernet) or wireless (radio, WiFi, cellular, etc.) transmit data to a receiver that then aggregates the data from one or more devices; this method is appropriate when you need real-time data, need to receive alerts, and when you need to manage a lot of devices
Other topics covered included datalogger software and data management, calibration, and a group activity in which we had to choose (and justify) a monitoring system for one or more specific scenarios. This activity was my favorite part of the workshop, and I wish we had spent more time on this. It was a practical test of how to figure out why and what you need to monitor, and how to maximize your resources to achieve that goal.
Helpful handouts included charts of various datalogger models/systems with comparison of many variables including costs. Options to consider include: connectivity, size and aesthetics of the logger, battery type and life, sensor quality, data capacity, cost, accessibility of the device once installed, built-in display of current readings, display and/or communicate alarms, sampling rate, calibration method, probe option, and software platform compatability.
Here are some take-aways that for me will inform my upcoming work:
- The landscape of available hardware is rapidly changing with developments in communications technologies; Bluetooth is the hot technology according to several vendors, so they are investing their development efforts into Bluetooth connectivity for their upcoming upgrades and new releases
- Sensor quality matters, but there are also differences (reflected in the wide range of prices) in everything else around the sensor…most notably the architecture of the device, the circuitry and algorithms used to translate the sensor data into numbers. You get what you pay for, but that should be matched to what you need.
- Sensors are very sensitive to organic vapors! They can be destroyed by a big whiff of solvents, and even thrown off by off-gassing from the plastic housing in which they are mounted.
- Loggers need to be checked for accuracy (you can do this yourself with saturated salt solutions according to instructions in another helpful handout), and if they have drifted, they need to be recalibrated (some you can do yourself, others have to be sent to the manufacturer); battery replacement is also variable (some are DIY, others not).
- Most connected loggers require IT support for installation in an institution, so include your IT staff during the planning phase; be sure to ask them about WiFi encryption requirements
- Wireless technologies may be affected by building/exhibit case material and construction, as well as nearby noise-emitting sources
- Software varies a lot, but some of the systems can import data from other manufacturers’ devices; again, you get what you pay for, but the options I favor include the ability to import climatic data, graphical visualization of the data in a format that’s understandable by a range of audiences, and good tech support.
- Get a demo set from the vendor prior to purchasing the whole system to make sure it works for your building
At many points throughout the Collections-Care focused Annual Meeting, I noticed that careful environmental monitoring and interpretation of the data becomes a fundamental part of energy savings and decision-making, grant-funding and construction/renovation of storage spaces. I almost wish the workshop had happened right after the meeting instead of before, because I would have had many more big-picture questions to ask of the presenters. Mostly, I want to hear a more substantive discussion about why we monitor, and how to translate the data into words that advance preservation priorities. Environmental monitoring is a time- and resource-intensive process, so we should be thoughtful and strategic about it.