SDS100/SDS200: SDS200 using R8 radar detector GPS?

[EAFrizzle]

Does anyone know or have experience using the Uniden R8 radar detector as GPS source for SDS scanners? It would be nice if it does work just to keep more clutter off the dash.

 

[jtwalker]

This information describes what you would need from your radar detector gps. I'd say it is doubtful that anyone knows if this combination will work or not, and even more unlikely that it will work.

The GPS device must have a serial (RS-232) output, and be capable of outputting standard NMEA-0183 v3.01 compliant location data, and GGA/RMC data sentences at 4800 bps.

 

[Ubbe]

You can route out the TX signal from the radar detectors GPS chip, that uses standard NMEA protocol. Then in the scanners GPS setting you can select the proper bps speed that the chip are set to use in the radar detector, that will probably be 9600.

Look inside the radar detector and locate its GPS chip and look at that chips specification what pin that are TX serial data. But it can be a chip that uses USB data signalling that cannot be used without using a converter circuit, like a small $10 Raspberry Pie Pico or similar CPU.

/Ubbe

 

[Ubbe]

The R8 uses the Quectel LC76F GPS chip and defaults to standard UART 9600 mode but only handle up to 2,8v signal levels. You will need a voltage converter chip as are used when modifying Unidens scanner to have an internal GPS receiver and can be found explained here at RR, or use any similar chip that works as a voltage buffer.

The TX data are on pin 2 at the GPS chip but it also has a I2C interface that could be used to configure and handshake with the chip and I don't know if there's a command to switch off the pin 2 data but it's probably still operational.

Some soldering required to a voltage converter chip, that can be in the radar detector and then a 3,5mm jack installed to be used with a cable that connects to the scanners RX data pin for GPS.

/Ubbe