Garmin Hacking Project

Garmin Hacking Project

If you don't want to pay Garmin for their expensive connector for the GPS38/40/45/90 then check out the first sharehardware project for a low cost connector from the Purple Open Project.

This page is not about hacking the map formats but is about an older issue with 8 channel GPS units and doesn't effect any Garmin GPS reciever made in the last half decade.

The GPS45 has a 90.0022kt (104mph) speed limit. It was our intent to find a way arround this.

It is also our intent to publish full details on the Garmin Protocol

Garmin Protocol (John F. Waers' version)

Garmin Protocol (Bill Soley's version)

Tom's photo

GPS40 GIF format

Bob's GPS45 Internal photos

PCBoard (65K)

Backside of the display (28K) The ROM is the chip on the bottom right side. Its left side is next to the three verticel bands. The area to the left is where the keypad makes contact. The LCD is the blue rectangle on the top and the backlight is white and on the right.

I also have a 5+M JPG image of the circut board. I'm working on a way to get it to people. It's too big for this server.

Graphics Archives

These are old gopher: links
GPS40 in UUENCODED BMP format or GPS40 in UUENCODED GIF format.

This document was created by Tim Hogard (

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 This page was last updated Saturday, 05-Nov-2005 23:30:50 UTC Copyright 2000-2020 thogard™ is a trademark of Tim Hogard