View Full Version : DIY GPS project

13th September 2005, 03:24 PM
I'm always keen to show off my projects so what better way to use my first post...

It has/does..

256Kb non volitile flash + a little more memory used for waypoint/logging/early warning, etc, minature joystic similar to playstation ****ogue stick, 6 digit LED display and blue 2x16 char LCD.
! watt amplifier and dual freq sound routines.

Can display 24 hr time on both LCD and blue LED screens and has alarm.
(clock display shown in pictures)
can log and display speed on a second by second basis for well over 3 hrs with the memory that is allocated to this function, also shows top speed per session on LCD.

can show position fix information, has early warning system mode for school zones, etc. has distance to waypoint mode using Pythagoras' theorem to calc distance in Km from waypoint.
Has lat&longitudinal difference display (not available on consumer GPS units)
displayed in degrees from waypoint (ie waypoint becomes 0 degrees lat and 0 degrees long, and your position is displayed from this reality).

Tracklog style function records position (coordinates) on a second by second basis for thousands of waypoints (a few hours) with high resoluton waypoints.

The whole thing is going in an enclosure made entirely of welded aluminium checkerplate and glass window :)

I am available for contract work for custom GPS intallations/microcontroller programming
(******** only of course, no gay car projects).
Cheers, Art.

13th September 2005, 03:39 PM
WOW Art... Thats really ****** impressive dude! :eek: What kind of time goes into designing and producing a unit like this?

13th September 2005, 03:45 PM
Many nights off work to stay home sorting out software issues :D
You probably already know that most of the way small devices work
these days is in software that is loaded onto the chips. this unit has two
programmable microcontrollers. The hard ware is the easier part.

I would say a couple of months to make this, although I diidn't count actual hours...
but it would be quicker to make other GPS projects now that I have a lot worked out.

It was supposed to be primarily a clock that never required the user to set it, but expanded from that.
thanx for the comment :)

13th September 2005, 10:02 PM
Well not many people can claim to have designed and built their own GPS!!

Now how about the mapping version ;)

Another "home made" job......this time from Mikhail. (all Hail...Mikhail! :D )
Game Boy GPS?? (http://www.msh-tools.com/GBA/gbagps.html)

14th September 2005, 08:07 AM
Hi Art,

What flavour MCUs did you use?

14th September 2005, 11:08 AM
They are pics :)
16F877 @ 20 MHz, 16F628 @ 4 MHz for the micros,
24LC256 x 8 EEPROMs to total 256Kb.
There is a real time clock as well that was supposed to be set to GPS time,
but I broke it somewhere allong the way. There is a real time clock in the
GPS mouse anyway.

I am going to use pic 18***x for my next project running at 40MHz,
and at least 1 Mb of memory. Also want to use a Speakjet IC to give it
a speaking voice.

14th September 2005, 11:38 AM
Yep, I know those PICs well. Two of may favorites.
I'll be interested in seeing your progress with the 18 series, I've never used them myself.

5th November 2005, 04:59 PM
Looks like an interesting project. I am into the dark side (AVR's) myself.

Have you thought about using Printed Circuit Boards? They make the wiring much easier. I use precoated light sensitive boards that I expose with a normal fluorescent desk lamp. In this way, I can create tracks as small as 10 mil. It makes the whole board a lot smaller and neater.

Once you've made the first, if you need to replicate it, there's a lot less wiring - just some drilling of holes.

5th November 2005, 06:31 PM
An easier way still is to use direct transfer, using a laser printer with matte inkjet paper, then iron it on to a copper board, rinse and etch. If you've got access to a laser printer, it beats muching about with photoresist, timing UV lights, developing etc. I've had some really good results with this. Google can provide all the information you need, down to which brands of paper work best :)

10th November 2005, 07:25 AM
I've done a lot with microcontrollers & electronics, I should have tried my own
PCBs by now but have never gotten round to trying. I'm sure my first effort will
be a mess.

Others have designed and made PCBs for projects that I have shared over the
net though, and I usualy end up with one. So I do have a couple of my own
projects made with proper PCBs.

Now how about the mapping version
My current project is quite exiting, a moving map GPS for the Sony PSP! :)
I am going to use the same Garmin GPS mouse pictured in this thread.
It is easier than it sounds. There is a secret serial port in the PSP's headphone
connector used by the remote control device biult into the headphone chord ;)
Cheers, Art.