DIY GPS?

[+Not_Tasha]

Hello! I'm new to the forum and Geocaching, I'm also a Maker. So far I've been using my iPhone for Geocaching and I started wondering if anyone has tried building their own handheld GPS (rather than buying one)? I have an old GPS that was left in my car and I'm thinking of trying to re-purpose it.

 

Thanks!

[+splashy]

Some did this about 20 years ago, nowdays the units are so cheap it makes no sense.

And the really sophisticated ones are very hard to make (i think).

If you want to do it because of the price, it want work.

[+lee737]

Wouldn't be hard - just a microcontroller chip and a GPS chip with an LCD display should be able to give you a co-ordinate readout, some programming skill should be able to give you a heading/distance reading.... Unless you are very savvy it would be pretty basic (and probably bulky!).... the May 2014 Silicon Chip magazine here in Australia showed how to interface one particular MCU to a GPS to get the time readout, wouldn't be hard to get the position. I agree it would likely cost you more, and you'd spend a chunk of GC time mucking about doing it, but it could be a good learning exercise....

Lee

[+MKFmly]

Build one from Lego...

 

http://www.bartneck.de/wp-content/uploads/2009/02/project-report-martijn-ten-bhomer.pdf

[robertlipe]

The building blocks are really easy to get and assemble these days. If you have reasonable electronics background a trip to a place like Adafruit or Sparkfun makes it pretty easy to check off the main components: a GPS module with antenna + a microcontroller + some kind of input device, ranging from a joystick to a dpad to a touch screen + some kind of a display ranging from a couple of LEDs to a 2 line serial device to 128x128 tiny screen to a tablet scren + some kind of battery + a mere matter of programming. Then you have to get the thing small enough that you'd actually want to carry it and atomic enough that carrying it into woods shouldn't horrify you.

 

Or you could buy hardware for less (hint: a Moto G is actually a quite reasonable piece of hardware for this and goes for ~$65 OFF CONTRACT, making it a favor of robotics and drone builders - you get WiFi and sound and cameras and such "for free") and focus on "just" the software. Programming in Java is a heck of a lot less frustrating than bit-banging a PICaxe, an Arduino, or even a Pi, and actual EEs and actual manufacturing people have already worked out things like not bursting into flames when you misprogram the LiPo limiters.

 

Overall, do it for a learning experiment and not because you're going to make hardware "better" than what you can buy.

[+ecanderson]

Overall, do it for a learning experiment and not because you're going to make hardware "better" than what you can buy.

Last sentence makes excellent advice!

Perhaps the OP can create a design that incorporates a 3 axis 'compass' chip, and while he's at it, assure that the supply voltage to it is regulated such that he needn't have to 'calibrate' it when battery voltage changes with use (something Garmin still hasn't figured out!)

[+Chrysalides]

One approach to the DIY geocaching GPS :

 

http://smstextblog.blogspot.co.uk/2014/01/cacheberry-pi-in-detail.html

 

This approach is probably easier to someone who is experienced in Linux but has only limited exposure to microcontrollers.