Read TTL signal coming trough USB

[Feignedjesse2]

Hello Everyone,

I'm currently working on a project for my internship. For this project I need to connect a GPS to my PC. So far i've got hardware that outputs an NMEA sentence in asynchronous serial connection (TTL). Here you can see the connection diagram from the board. Now I need to connect this to PC so that i can get the bits into labview. My current idea is to use an FTDI Cable to convert the TTL data to USB and plug that into the PC.

Now i have a couple of questions:

-Is this a good way to connect the device to my pc

-How do i collect the data from the USB in labview

-Do you guys have any idea's regarding connection/data readout to make it better or use a completely different approach?

Kind Regards,

Jesse Bax

Student Mechtronics

[RTSLVU]

I would suggest a USB to TTL serial converter like the TTL-232RG from FTDI. 

http://www.ftdichip.com/Products/Cables/USBTTLSerial.htm

If you have never used one they look and operate just like a Com port, nothing special needs to be done in LabVIEW to use them.

Now you can probably find cheaper ones but beware of cheap "Prolific" USB-serial adaptors. As there are counterfeit Prolific chipsets floating around that will give you problems, stick with real FTDI chipset adaptors.

[RTSLVU · Accepted solution]

As for "collecting" the data.  NMEA compatible GPS continually send data in the form of NMEA "sentences", you do not querry it.

These sentences are just ASCII text, you will need to capture and parse the text to get the information you want.

Here is a good discussion on decoding NMEA sentences.

http://www.gpsinformation.org/dale/nmea.htm