c50

The Cheeta c50 is a GPS console that provides a great protection against static speed cameras and other static or foreknown hazards. It uses an update file (.hdr) with the coordinates and azimuth of the dangers ahead. Since the console should be updated on casual basis, an update pack should be purchased aside the console. to gain access to the actual speed traps and dangers. Without it the user will not be notified about new speed traps.

About a year ago I bought the c50 v7 and figured that there is a chance I could home-brew an update file without paying for a binary presentation of freely available widespread information.

To make a long story short,

Cheetah c50 with homebrew DB

Here are some funny things about the c50.
1. The c50 allows one to save Points of Interest (POI) and export those POI to csv. This is the format the c50 crew was using: The lat\longitudes are deserialized to int and gain a decimal point after the second digit.
example:

Serialize
34.71337 -> 3471337 -> 0x34f7e9 -> 0x0034f7e9 -> 0xE9 0xF7 0x34 0x00

The same serialization is used for the DB coordinates.

2. Most of the READ/WRITE functions send a hard coded command to device. However, the UpdateDB function was not implemented that way. It seems as if the command telling the device to update it’s DB is a part of the update file (and perhaps the .hdr extension of the update file stands for header).

My research and production scripts can be found here

I would like to thank
Ruby Feinstein
Zeev Greenberg
Tamir Mayer
Mark Bloch
aandy on freenode

For their kind help and support