Build your own datalogger

The mapping datalogger is key to our project. You can build one– all you need is an inexpensive netbook computer that you are prepared to wipe the hard drive on. You’ll also need a USB GPS device that can send packets– something such as a Garmin GPS18 USB , Garmin GPS 18x USB, or any GPS unit that can speak NMEA packets to the Linux GPSD daemon. This version of the mapping software is also capable of taking temperature readings through a Vernier GoTemp probe.

One excellent way to proceed is to install a blank, unformatted solid state drive (SSD) in your netbook. Then, just by swapping the drives out, you can put the computer back to how it was before the datalogger installation.

Don’t try this installation unless you are reasonably comfortable with UNIX and unless you have an old netbook you are willing to sacrifice.

  1. Boot the computer using a bootable linux USB stick (many websites can help you set one up. All that matters is that you must be able to run a terminal session).
  2. Download the disk image named 4Gt and put it on another USB drive. This file is VERY LARGE (4GB) so you need a good connection.
  3. Type the following command to identify the hard disks:ls -alt /dev/disk/by-idYour hard drive should be drive sda. The USB drive with the disk image will likely be sdc1
  4. To erase (permanently and irrevocably) your hard drive, type the following command:sudo fdisk /dev/sda (or substitute the correct drive assignment. BEWARE: This command will ABSOLUTELY and PERMANENTLY erase the disk)
  5. Mount the USB filesystem containing the disk image with the following commands:sudo mkdir /media/Jsudo mount /dev/sdc1 /media/J (adjusting the drive assignments as needed)
  6. Copy the disk image onto your blank, unpartitioned hard drive with the following command:sudo dd if=/media/J/4Gt.img of=/dev/sda (adjusting the drive assignments as needed)

That’s it. Now, when you boot your netbook, it will boot into LINUX, with a fully functional copy of the mapping datalogger as detailed in the Media Kit. A small boot partition and a swap partition (which appears as a volume with a swap space inside) will have been created on your hard drive; the remainder will be unallocated. If you boot again from the USB stick, you can use

sudo gparted

to move the swap partition to the end of the unallocated space. You will likely need to do this in several steps, by choosing the swap and setting it to “swapoff” and then by resizing the enclosing partition to use all unallocated space. Then, enlarge the enclosed swap to fill the entire swap partition. When this is complete, resize the swap to about 256mb by moving the start of the swap, and follow this by resizing the swap partition to minimum size. Set the swap to “swapon” and then resize the boot partition to maximum size.

Finally, you can rename your computer by typing

sudo su

echo “yourname” > /etc/hostname

and substituting whatever you want for “yourname.”