Pressure Sensor and Data Logger Sorry...this product is no longer available. Shipping weight is 2 lbs., includes pressure and temperature sensors, software, cables, connectors, instruction manual and battery, as shown. Requires a serial port connection (USB to serial port adapters can be used for this.) Temperature sensor wire is 12 feet long. $129.00   ...item# 1868

Sensor unit is 3.75 x 2.38 x 1.00 inches

This product, called a "Weather Jack," is a remote temperature and pressure sensor and data logger (ie it stores pressure and temperatures unattended) that can be read at any time by connecting it to a PC with a simple phone cord into a serial port connector for your computer. All connectors and cables are provided, as well as the 9v battery that runs it—for a year or so. Temperature and pressure can be recorded at any interval, from a few minutes on up. At 15-min intervals it will store 5 days of data; longer intervals store for longer periods. This is the same pressure sensor used in the Jumbo Barometer, which is highly accurate and the offset is simple to set to get correct sea level pressure. The temperature sensor could be used for sea water temperature or air temp... we have had one sailor use it to monitor their fridge temp. Hikers can use it to record elevation changes during some outing, which they replay and plot when they get home. (Formulas and procedures for deriving elevation from pressure are in the Resources Library under Miscellaneous.) The data are stored in the PC as simple text files that can easily be imported into a spread sheet or data base for comparison with other measurements... as done below. These devices are ideal for detailed recording of the approach and passing of weather systems. A sample of a front passing over us in the Southern Straits of Georgia yacht race is shown below. The blue data are from a weather jack in a sail bag, the red data were provided to us by Environment Canada a few days after the race. For the first few hours, the sail bag with Weather Jack in it was not on the boat but at a higher elevation at the hotel, hence the early discrepancy with sea level pressures. Note that you can even see 1-hour trends being reproduced in the measured data. This graph is a direct output from an Excel spreadsheet plot. Our measurements show that the relative and reproducible accuracy of the device is ±1 mb. This means that if you set the device to to a proper accurate pressure, all subsequent pressures read from the device will be accurate to within ±1 mb. Below is a screen shot of the software interface to the device from the PC. Or you can customize the interface and not use the software that comes with it. The data are stored in a simple text file that can be imported into Excel and your own graphic display created. The sensor can be interrogated with Hyper Terminal to update the data log in the PC and extract data. Using this method you can also change the sample times to any interval you choose, whereas the packaged software limits sample intervals to 15m, 30m, or 1 hr. Regardless of how it is set, a total of 127 measurements can be stored. At 1 hr intervals, you have some 5 days of data; at 1 min intervals you store about 2hr of data. After the 127 points have been filled, it will start to overwrite the earliest ones with new data. Note the unit is shipped with a floppy disk, but the software is online for download, so no floppy drive is needed. Also manual does not say it, but the software provided will run on any version of Windows. The new optional 3rd party software (see below) has a more modern and versatile interface. The temperature sensor: You can attach the sensor to a pole and the pole to a stanchion so as to measure the water temperature underway. This is extremely valuable sailing in the Gulf Stream for noting your location within main streams and meanders, and it is also valuable sailing in the tropics since waters above 80°F could be breeding grounds for tropical storms, and cooler waters are not. The sensor is accurate to ±1°F. New optional software. Sailor and software developer Harry Bird has created an excellent custom software interface to the Weather Jack. It has enhanced features and a more versatile interface than the basic software that comes with the product. You are welcome to download and run a full featured demo version of the program with or without the Weather Jack attached for 30 days to see if you would like to buy this optional software. The optional software price is $49. Download demo version. If you choose to purchase the optional software you can do so here. Item #1868c $49, Buy Now. Unique new barometer calibration resource at www.starpath.com/barometers. Go to that page, enter your latitude and longitude and elevation, and it will tell you the 10 closest sources of accurate pressure with a link to each one. There is also an instructions sheet with work forms. View Weather Jack manual (250kb pdf) Compare electronic barometers we offer Compare devices similar to Weather Jack There are not many (if any) devices of this type available in this price range, ie a pressure sensor designed to be controlled and read by your computer that also serve as a data logger. Refer to The Barometer Handbook for a review of sensors and barometers. The Weather Jack, even with the extra $49 for the optional software, is still many hundreds of dollars less than the nearest product with similar features. Personal calibration option is available for this sensor, with which you will be able to obtain pressures accurate to about ±0.5 mb. The measurements at each pressure are compared with our certified in-house National Institute of Standards calibration barometer and documented on the certificate.