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Serial Comm Question — Parallax Forums

Serial Comm Question

CenlasoftCenlasoft Posts: 265
edited 2012-04-10 09:07 in Propeller 1
Hello,
I have a serial signal coming out of an android phone from the audio port with a 5v level. I want to use the prop to view the results using the parallax serial terminal. What are some hardware considerations do I need?
Thanks,
Curtis

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2012-04-09 13:53
    Put a 4.7K resistor in series with the 5V serial signal coming out of the Android and that will protect the Propeller I/O pin from the excess voltage. If the serial signal is really a modulated audio signal, you'll need more than that. The details depend on the nature of the signal including specific voltages, waveforms, and timing.
  • LeonLeon Posts: 7,620
    edited 2012-04-09 13:57
    What format are the serial data and what software is producing it.
  • CenlasoftCenlasoft Posts: 265
    edited 2012-04-09 14:36
    Hello,
    I am using an earphone jack from the android to a 4.7k resistor on the signal line to the inverting pin of the lm324 op amp and a 5 volt divider to the non-inverting pin. The output pin of the lm324 goes to a 100 ohm resistor to the scope. I see a signal from 60mv to 4.1 volts modulated coming out (squarewave). I use the voltage divider to set the threshold for the baud rate. I used the circuit and the android serial software from: http://robots-everywhere.com/re_wiki/index.php?title=Serial_on_Android_using_the_audio_port
    Thanks,
    Cenlasoft
  • prof_brainoprof_braino Posts: 4,313
    edited 2012-04-09 16:25
    The link you provided seems to tell us all the stuff needed.

    You've used the circuit and software provided, what hardware considerations are you asking about, the micro controller?
    In the video, he's using a propeller proto board. That or any stock prop board should work, as the prop chip is always the same.
  • CenlasoftCenlasoft Posts: 265
    edited 2012-04-09 17:42
    Hello,
    I have all the prop boards that parallax makes. In the video, he never elaborates how he hooks the prop from the output of the lm324. At the end of the web site he states to use a picaxe chip. I have one, but I prefer to use the prop. The picaxe is a 5v chip. Thanks,
    Cenlasoft.
  • prof_brainoprof_braino Posts: 4,313
    edited 2012-04-10 09:07
    I would suggest contacting the author directly. If you get a response, please let us know, this is kind of cool and I think a bunch of us would want to use it. Unfortunately my new projects queue is already overflowing and I must limit myself from starting too many new directions.

    Keep on it!
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