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Topic: Can't read data from GPS module (Read 4152 times) previous topic - next topic

CompWiz17

#30
Oct 15, 2011, 11:55 pm Last Edit: Oct 15, 2011, 11:57 pm by CompWiz17 Reason: 1
Yes, the signal is being inverted, but it requires external circuitry, as described above.  

I'm just saying that it would be nice if we could eliminate some of the circuitry, make converting from rs232 to ttl simpler.  

I mean, if we can eliminate the external not gate, then that would mean you could convert a 5v rs-232 signal to ttl using only a diode and a resistor.  Or, maybe even eliminate those as well, since the arduino already has something built in to eliminate negative voltages. 

zoomkat

Quote
I mean, if we can eliminate the external not gate, then that would mean you could convert a 5v rs-232 signal to ttl using only a diode and a resistor.


If you look at the below, I inverted 12v rs232 to 5v TTL just using two resistors and a transistor from Radio Shack. Some times it is easier to just do it and move on.

http://arduino.cc/forum/index.php/topic,74650.msg562845.html#msg562845
Google forum search: Use Google Advanced Search and use Http://forum.arduino.cc/index in the "site or domain:" box.

N2NXZ

So,just for fun...what was the solution to the original question here??? :)

CompWiz17

#33
Jun 09, 2014, 08:52 pm Last Edit: Jun 09, 2014, 08:55 pm by CompWiz17 Reason: 1
Well, as I described in the thread, an RS-232 signal can be converted to TTL serial(which the arduino can read) using a simple circuit.  That is, a diode and pull-down resistor to convert the -5V signal to 0v, then a not gate to invert the signal. 

We used this circuit successfully in the Space Balloon we launched, years ago. 

Was there something else you were wondering about? 

N2NXZ

No,just seemed like a question that could have been answered long before talking about servos and card readers...lol.
Hard to find solutions on forums nowadays without going through endless non related topics.
Thanks for the reply.

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