Hobo Data loggers to measure soil water potential and soil or air temperature data


A watermark sensor was connected to a hobo data logger and the voltage of the sensor recorded hourly. The hobo also has a internal temperature sensor that was recorded.

The Software to talk to the hobo is BoxCar Pro from OSET computer which sells the data loggers and software. The cost of the data logger for this type H08-002-02 is around $100


 1. First you must launch the data logger and because this is done at the location of the data logger in the field which is normally outside, it is best to use a mini computer that is easy to read in sunlight. The operating system has to be XP  to run the software.



2. At the time of launch, you can select the time interval that you desire the data logger to use. The shorter the time interval the sooner you must download the data before the data logger storage is full. For soil moisture and soil temperature a 1 hour time interval is sufficient.


boxcar 3

3.  You can turn on or off the channel in the data logger depending on what you want the data logger to record.



4. When Lunching the data logger all data is erased. You normally would read the data first and then launch the data logger.



You can purchase the watermark sensors from Irrometer . The wiring diagram for the watermark sensor is given at this web site.  You will have to purchase a stereo cable 2.5 from onset computer and a 10 k ohm resistor that is a rated as one percent accuracy  and 1/4 watt from http://www.futurlec.com/ an electron supply store online.