Nmea input circuit anyone.

[mattnj]

Does anyone have a proven nmea input circuit (with optoisolation) I can use on an arduino project at 3.3v....it's not difficult to get something working and I have done...but I am not totally confident on the circuit being compliant to the standards for 4800 and 38400 baud, with the correct protection, current draw etc...for the -15v to 15v and the 5v-0v range... obviously I've had a good Google about and can't see anything obvious. Thanks in advance.

 

[dolabriform]

This will do the conversion to RS232 and back again to/from standard TTL arduino pins. It will handle up to +/- 30v.

https://www.ebay.co.uk/itm/RS232-To...e=STRK:MEBIDX:IT&_trksid=p2060353.m2749.l2649

Data sheet is here:
http://www.ti.com/lit/ds/symlink/max232.pdf

I'm not sure if it's opto isolated tho.

 

[GHA]

This will do the conversion to RS232 and back again to/from standard TTL arduino pins. It will handle up to +/- 30v.

https://www.ebay.co.uk/itm/RS232-To...e=STRK:MEBIDX:IT&_trksid=p2060353.m2749.l2649

Data sheet is here:
http://www.ti.com/lit/ds/symlink/max232.pdf

I'm not sure if it's opto isolated tho.

:encouragement:

I've used those, cheap and easy - though ISTR the pins are a bit odd, pin 3 is the input on the 9 pin D though might be false memory.
Also, if you power the adapter from 3.3v then the TTL output is 3.3v as well, RS232 voltage out can't remember but it worked.