LabPro and CBL 2 can collect data without being attached to a computer or calculator. Long-term remote data collection can easily be done with either of these interfaces by batteries. The maximum duration of data collection depends on which sensors are used and the data rate chosen. The graph below shows temperature data collected on seven LabPros over a period of 10 days. The LabPros were positioned throughout our building and collected data at a rate of six samples per hour. The same seven LabPros were used for two more 10-day data collection runs. After 20 days, all seven LabPros were still going strong. At the end of 30 days, three of the seven sets of batteries were dead.

Temperature of the Vernier office over a period of 10 days collected on seven LabPros positioned throughout the building.

Some sensors, such as our CO2 Gas Sensor and Dissolved Oxygen Probe, need to have continuous power supplied to them. This limits the length of time you can collect data in the field, but with a little planning, you can have a successful experiment. The CO2 Gas Sensor will last approximately six hours when powered by four AA batteries. The Dissolved Oxygen Probe should last eight hours. The data rate does not affect the power usage in this case, since the power to the sensors is always on. If your experiment calls for data collection over an extended period of time, the External Battery Cable (order code EBC, $6) allows you to use a 6-V lantern battery to power your LabPro or CBL 2 when AC power is not available. This makes it possible to collect data with the CO2 Gas Sensor for up to 54 hours and for approximately 72 hours with the Dissolved Oxygen Probe.

While this is only one example of long-term remote data collection, it provides some good guidelines for planning your next remote experiment.