Detecting NMEA data transfer

[Kurrawong_Kid]

Is there anyway I can detect whether data is being transmitted from a windvane unit towards a "Tiller pilot"?
(apart from the set up not working!). I presume a multimeter can't do the task. Could a PC be used and, if so, how? Not sure whether the problem is my wiring or failure of unit to transmit.(Nasa Clipper)

 

[exapp]

Hello,

I've found a multimeter will allow you to detect the talker. I use a digital meter and you see the voltage going up to about 3.5v and back to zero. Just lets you know something is being transmitted....obviously you can't see which sentences.

My meter also has a little digital indicator to show the voltage on a scale and with NMEA talkers it looks a little bit like "Knight Rider's" sweeping red display on the front of "Kit"

Now if only i could make it talk...."Michael you have located NMEA"

Regards,

Exapp

 

[Kurrawong_Kid]

Many thanks, I'll give it a whirl!

 

[BruceDanforth]

With a bit of trickery you can use the soundcard on your PC as an oscilloscope. Be careful or you will blow it up and at the very least read the faq. You will need to buffer the signal through some kind of an op amp circuit with appropriate gain. There is software here to do it.

 

[dalex]

Very easy way to 'listen'to nmea. Connect an old car radio speaker across the data terminals when the nmea data is supposed to be talking. You will hear a regular scratch sound, very faintly.

If you wish to analyse the data, you need a serial connection to a laptop etc, but set the com port up so the port is 4800 baud 8 bit no parity and use hyper terminal to monitor the com port of your choice.

 

[Talbot]

eveneasier way is to get an led of the right voltage from maplin and connect that into the ground and the tx side and that will show if data is moving. (make sure the led is the right way round!)

 

[ShaunG]

As Dalex said, Connect NMEA In/Out and ground to pins 2,3,5 on a DB9 9 pin serial socket, use hyperterminal set at 4800/8/n/1 and you can see the data being transmitted, i can send you details of a specialist lead you can make that will allow you to see the data in both directions

Regards

Shaun

 

[steve28]

What make off tiller pilot are you using, with a raymarine st1000 or 2000 the tillerpilot detects the signal itself by displaying W in the displaywhen activated