UUB BioLogs
From 2000 feet below the Antarctic ice to 15,000 feet in the air, these tiny low-power physiological data loggers open new research frontiers
UFI initially developed the UUB BioLog for the Paul Ponganis Lab at Scripps Institution of Oceanography. Their ongoing studies of the diving physiology of emperor penguins had utilized our 3991 BioLogs for several years. These birds dive to depths of up to 1750 feet (534m) below the Antarctic sea ice, so the loggers require thick-walled pressure enclosures.
In 2009 we designed the Universal Underwater Biolog (UUB). The "universal" part was intended to convey the message that this logger would support signal conditioners beyond just the ECG functionality initially requested. And indeed, by adding a tiny 3-axis MEMS accelerometer chip to the 0.55" by 2.000" (14mm x 50.8mm) "core" board, we went a long way toward meeting the requirements of the five additional customers listed in the next section. Small added "daughterboards" piggy-backed onto the core boards met the remainder of their hardware requirements. Additions to the firmware for the logger microprocessors and to the PC host software did the rest.
Early UUB applications
- UUB/4-EIAP for Weddell seals: Researchers at Texas A&M and UC Santa Cruz asked UFI to build them a system to log ECG and IBI (interbeat interval), 3-axis acceleration and seawater pressure. This system was deployed in 2009 on ambulatory Weddell seals near McMurdo Station, Antarctica. The seals traveled several days between instrument deployment at holes in the sea ice and later recovery there. Since Weddell seals dive to depths of 600 meters (2000 feet) below the ice, strong pressure enclosures were essential.
- UUB/3-EIA for dolphins: A joint US Navy/UC Santa Cruz research team requested a data logger for use in the Navy's Marine Mammal Program. In June 2009, UFI delivered a logging system to allow them to record ECG and IBI data from ambulatory dolphins swimming at relatively shallow depth.
- UUB/3-EA for condors: The California Condor Ecology & Management unit of San Diego Zoo's Institute for Conservation Research asked whether UFI could construct an ECG and two-axis acceleration logger to soar on the backs of the free-ranging birds, potentially to 15,000 feet (4.6 km). A first system was delivered in December 2009; in May 2010, UFI delivered a much-improved system. In the newer system, the accelerometer helps conserve memory and battery power: when measurements indicate the condor has roosted for the night, recording pauses. Data logging resumes only when accelerometer activity again shows flight behavior.
- UUB/3-EPT for geese: A research associate at the University of British Columbia asked UFI to design a logger to measure partial pressure of oxygen (PO2), as well as ECG and acceleration. UFI delivered the loggers, which will be deployed on geese, in mid-2010. First loggers will be tested in a wind tunnel; if all goes well, later measurements may include free-ranging birds.
- UUB/6-EAPD for elephant seals: Research personnel at Woods Hole Oceanographic Institution asked UFI to propose a sophisticated logger to measure ECG, two-axis acceleration, sea-water pressure and oxygen saturation. In a first phase, the logger will be deployed to study the diving response of elephant seals; the recorder later may be deployed on even larger marine mammals.
Currently Available Signal Conditioners
- ECG -- Animal ECG is a good overall indicator that can hold a lot of information. Gain and offset can be adjusted to the application with 1,000 to 2,000 typical. The signal conditioner supports two inputs plus an optional reference.
- IBI -- Where the ECG signal is available, a built-in firmware module can be added to scan the ECG at 1000 Hz., then peak-detect to locate the R-wave spike. Careful timing supplies the Inter-Beat Interval, or IBI, in milliseconds, which can yield even more information about your subject.
- PO2 -- The electronics for this popular channel are configured to sense blood PO2 levels using a Licox catheter type PO2 probe. This probe gets surgically implanted into the artery or vein of interest prior to releasing the animal for recording.
- Temperature -- A simple thermistor connects to this circuitry to supply a temperature channel. Where the PO2 channel is included, a catheter type Thermistor probe can also be used to supply PO2 probe temperature for correction purposes. (Where the temperature characteristics are known, this can be omitted.) Ambient temperature and other uses are possible for this channel.
- Pressure/Depth -- An industrial grade stainless steel pressure transducer can be included in the enclosure for underwater applications. Ported to seawater, this transducer supplies external pressure which correlates nicely with depth, where this is an important variable.
- Acceleration -- A 3D Acceleration sensor can be included on the UUB main board. Orientation, activity and effort are some of the quantities that can be extracted from the acceleration data.
Example UUB and customer-supplied housing
This data logger is the UUB/4-EIAP model, configured to measure ECG and IBI (interbeat interval), 3-axis acceleration and seawater pressure up to 1000 meters below sea level.
The single 3.6V AA lithium cell at left powers all channels for over 56 hours of recording time using 50 Hz ECG sampling.
UUB Selected Specifications
- ECG sampling rates: 25 Hz, 50 Hz, 100 Hz or 250 Hz.
- ECG full-scale voltage at input: +/- 2.5 millivolts
- ECG gain: 1,000 typical (adjustable)
- ECG sample resolution: 12 bits (about 0.6 microvolts at input)
- IBI sample rate: 1000 Hz for millisecond resolution
- Accelerometer sample recording rate: 20 Hz - 1 to 3 three axes
- Accelerometer range: +/- 2.0g (+/- 19.6 m/sec2) - all three axes
- Accelerometer sensitivity: 0.018g (+/- 0.18 m/sec2) - all three axes
- Pressure/Depth range: 0-1000m depth typical
- Logger memory: embedded microSD card
- Recording duration: as required, and depends on sample rates required. 30 days typical
- Assembled logger board dimensions: 2.00" long x 0.57" wide (typical). Overall dimensions depend on supported channels.
- Power supply: cylindrical 3.6V primary lithium cells recommended
- PC interfacing: Model 3991BIB interface box
- PC software: UFI BioLog DPS written to user requirements, for logger initialization and data monitoring, data download and saving, display, print
A Note about Pricing
Current pricing for UUB recorders can be found on our price list. Note however that these prices only include the actual PCB assembly supporting A-D conversion and data recording for the signal conditioner channels you require.
- Most outdoor applications will require some sort of rugged enclosure tailored to the specific animal and location. For underwater recording, the demands on the enclosure are even more stringent! There is no 'one size fits all' enclosure for the UUB recorders. Costs for the enclosure are specifically NOT included in the UUB prices. You can pursue this crucial piece yourself, or let us contact some vendors and see what we can come up with for you. Either way, the enclosure will be an important, separate cost item for your overall recorder budget.
- Connectors and transducers are also generally NOT included in the prices shown for the UUB recorders. Catheter grade PO2 transducers, industrial pressure transducers, even simple under-water connectors, such items can be very expensive! Which of these additional items you will need really depends on the channels you have in mind, and we can help you with your list of additional purchases.
Let us know what you need!
If you don't see what your UUB would need, drop us a line and tell us what you want! Most UUB solutions differ substantially one from another. Let us see what we can do for you.