Opto isolator circuit for NMEA>Wifi?

[GHA]

Cos there aren't enough half started/finished little microprocessor projects on the go

Think this would work OK to get NMEA 0183 down to 3.3v so an ESP32 can read it? Doesn't matter if logic is inverted, the ESP can sort that out.

Bigger picture is to have a circuit and parts list on easyeda/jlcpcb so anyone can order the bits and get the code online so make a little box which will transmit nmea over wifi and/or create its own network/webpage.

 

[mcetap]

I've built something similar a long time ago for converting differential NMEA to single-ended NMEA. It basically worked the same as yours.

Switch times might be just a bit slow with R2 = 10k. I think you should bring R2 down to 3k3 or maybe lower.

 

[GHA]

I've built something similar a long time ago for converting differential NMEA to single-ended NMEA. It basically worked the same as yours.

Switch times might be just a bit slow with R2 = 10k. I think you should bring R2 down to 3k3 or maybe lower.

Ta V much. Should have enough bits for a playaround onbord. Thing with ordering it all online with the circuit boards is that if you get it wrong it's another order from China.

 

[lw395]

You seem to have grounded the output?

 

[mcetap]

You seem to have grounded the output?

You're right.

 

[lw395]

It's so long since I did any actual NMEA, I can't remember if the + and - data lines source or sink current and whether a return to 'gnd' or a pullup or anything is needed?
Also if it's on the end of a long wire you might want a 220ohm or something termination, but I assume it won't be as that might negate the point of the wifi?
If you start adding terminations and more load in R2, you might actually have to check the opto has enough gain.