How to add a GPS receiver to the 9 Degrees of Freedom - Razor IMU - AHRS? - Discussions

The GPS model you are planning to use may have an impact on the most suitable connection in regards to direct compatibility with the existing parsers available in the libraries. In order to use gps units that require initialization, such as increasing baud rate or switching to a binary protocol, both TX and RX from and to the 9DOF to the GPS would be required leaving no uart connections left to transmit 9DOF+GPS data. I also have a couple of the 9DOFs laying around (non ITG3200 type) and have given some thought to this previously. I have an extra older GS405 (SIRF III chipset) GPS I was thinking of connecting to one of them.

The solution seems to be to add an extra uart to the 9DOF in manner that uses available pins and has

arduino support. The following is such a solution:

Breakout Board for SC16IS750 I2C/SPI-to-UART IC

sku: BOB-09981

http://www.sparkfun.com/products/9981

4 SPI connections will connect between this board and the 9DOF.

The SPI to UART output pins will connect to the GPS.

The 9DOFs EM406 is left free for sketch development and to provide the required Sensor+GPS data.

The arduino library to control this chip is here:

https://github.com/sparkfun/WiFly-Shield

Sparkfun forum discussing this this library is here:

http://forum.sparkfun.com/viewtopic.php?f=32&t=25216

If you're using a GPS that doesn't require full two way communication...disregard all of the above...lol !!!!

Replies

Michael Zaffuto July 7, 2011 at 6:56am

The GPS model you are planning to use may have an impact on the most suitable connection in regards to direct compatibility with the existing parsers available in the libraries. In order to use gps units that require initialization, such as increasing baud rate or switching to a binary protocol, both TX and RX from and to the 9DOF to the GPS would be required leaving no uart connections left to transmit 9DOF+GPS data. I also have a couple of the 9DOFs laying around (non ITG3200 type) and have given some thought to this previously. I have an extra older GS405 (SIRF III chipset) GPS I was thinking of connecting to one of them.

The solution seems to be to add an extra uart to the 9DOF in manner that uses available pins and has

arduino support. The following is such a solution:

Breakout Board for SC16IS750 I2C/SPI-to-UART IC

sku: BOB-09981

http://www.sparkfun.com/products/9981

4 SPI connections will connect between this board and the 9DOF.

The SPI to UART output pins will connect to the GPS.

The 9DOFs EM406 is left free for sketch development and to provide the required Sensor+GPS data.

The arduino library to control this chip is here:

https://github.com/sparkfun/WiFly-Shield

Sparkfun forum discussing this this library is here:

http://forum.sparkfun.com/viewtopic.php?f=32&t=25216

If you're using a GPS that doesn't require full two way communication...disregard all of the above...lol !!!!
Developer

Jani Hirvinen July 7, 2011 at 5:43am

Sure you can connect your GPS to it. Razor board have 1 uart port so to connect GPS you need to piggyback on it. Just connect your GND/TX from GPS to Razors GND and RX pins. Make sure that all serials are on same speed and voila, gps data starts to flow to it.

Then it's totally another story on what to do with this GPS data, you can echo it to razors TX and read it from somewhere else or what ever. That's up to you and your needs.

Sending PMs to core developers can be missed sometimes, we are trying to follow all queries as often as possible.

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