Re: Low cost GPS receiver?

[Gary E. Miller]

Yo Sanjeev!

On Thu, 30 Mar 2023 12:13:53 +0800
Sanjeev Gupta <ghane0@gmail.com> wrote:

> Gary, once an year, I ask for this, often on this list.
> 
> The "problem" I see with most modules like these is the UART voltage.
> (Nearly) all are designed for Aurdino, so they work on 3.3V (TTL?)
> logic. I think HAL would like to plug this into an RS-232 port in a
> "server", so he needs the +12/-12V signals.

I think others pretty well covered it.  So I'm mostly summarizing.

Many modern motherboards still have serial ports, no DB-9, they make you
buy an adapter to use the port.

Those modern motherboards will work with 0 to 5V data, but that is still
a problem if your GNSS receiver is 3.3V.

Raspberry Pi's have the opposite problem.  5V logic into a GPIO pin can
kill the pin.

So I keep a few 3.3V to 5V bi-directional level shifters.  Here is one
from Sparkfun:

https://learn.sparkfun.com/tutorials/bi-directional-logic-level-converter-hookup-guide/all

For real +/-12V, I keep some MAX232 boards around, like this one with
berg pins:

https://www.sparkfun.com/products/11189

I can use that to downconvert a +/- 12V receiver to connect to a Raspberry
Pi, or upconvert a 5V receiver to real RS-232.

And this one with a DB-9

https://www.sparkfun.com/products/449

Shop around, they can often be had for cheap.


RGDS
GARY
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Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        gem@rellim.com  Tel:+1 541 382 8588

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    "If you can't measure it, you can't improve it." - Lord Kelvin

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