[Barry Carter] had a Pretec compact flash GPS adapter for his PDA and really liked how it worked. The problem was it took up the CF slot so he wasn’t able to add any flash memory to the device to store larger maps. He opened up the device and discovered that it only had five wires attached to the compact flash portion. The lines came from an NMEA chip and he used a scope to figure out the port settings. All that was needed was an RS232 converter. With the new packaging he was able to plug the GPS portion into the PDA’s serial port and use a larger CF card for storage.

Continue reading “PRetec GPS Hack” →

[Chris Barron] is getting pretty unnerved by the UK moving to charging for road use based on GPS coordinates. He built this device to prove that GPS data can be spoofed and shouldn’t be relied upon. He promises future firmware updates that will provide two knob etch-a-sketch style path control.

Continue reading “GPS NMEA Spoofing” →

[stok] built this GPS receiver from the ground up. The GPS module he got off of eBay dumps NMEA 0183 data. He combined that with an old Nokia LCD and a PIC microcontroller. I like this project because it shows that you can build devices that the general public assumes are really complex.

Continue reading “Scratch-built GPS” →

Here’s a short guide for converting a Palm III GPS sled into a normal serial GPS receiver. The Palm III is old tech so its accessories can be picked up cheap and modified for other purposes. The GPS receiver needs to be separated from the Palm specific board and a few components need to be transfered between the two. Once that’s done you should have a standard serial GPS receiver. Here’s a cache in case the “Read” link fails.

[thanks nevamore, who has done this hack with success]

Continue reading “Cheap GPS Receiver” →

if you’re into geocaching, terraserver and google maps can be your greatest allies.  well, maybe second greatest, right after your trusty gps receiver.  with terraserver, you can pull up hires satellite photos and topo maps of just about everywhere in the continental us.  with google maps, you can easily pull up a road map and driving directions.

however, one thing i noticed when google maps launched was that it’s interface is conspicuously lacking a lat/lon entry field.  it turns out there are a couple of query parameters that you can use to pull up coordinate based maps.  with this info, you can make a simple form to pull up both map results for a given latitude/longitude combination, which should hopefully be a handy tool for your next gps treasure hunt.  continue reading to see how this works.

Continue reading “Howto: Geocaching With Google And Terraserver” →