• [KB6NU] Random stuff: Circuits for kids, replace a 555 with a PIC micro

    From KB6NU via rec.radio.amateur.moderat@21:1/5 to All on Tue Sep 28 13:43:09 2021
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    KB6NU's Ham Radio Blog

    Random stuff: Circuits for kids, replace a 555 with a PIC microcontroller,
    HF sports net

    Posted: 28 Sep 2021 07:30 AM PDT http://feedproxy.google.com/~r/kb6nu/tVpu/~3/85B1VhcLvWI/?utm_source=feedburner&utm_medium=email

    Circuits for kids

    A reader writes:

    I wanted to thank you for putting together your links page. My daughter MaryAnnes Girl Scout troop is currently working on their Think Like an
    Engineer Badge as part of the STEM series, and the radio schematics
    resources on your page helped us a bunch!

    MaryAnnes troop leader encouraged the parents to work with our girls at
    home to ensure we stay on track! The girls will be building a working
    radio, so the troop leader wanted the girls to learn the basics about
    simple electronics, circuits and electricity. She asked the girls to do
    some research online and to share their findings with the troop. Your page
    led us to some great websites to check out, so MaryAnne and I wanted to
    make sure we thanked you :)

    And if its not too much trouble, I was hoping you could include a
    contribution from MaryAnne on your website. She found this circuits guide
    that I was very impressed with

    All About Electronic Circuits


    Id love to show MaryAnne and her troop leader! Encouraging girls in the
    field of science and engineering is so important! And MaryAnne would be thrilled to know she could help! (She really got into tinkering during
    COVID, so she was very excited to work on this project!)

    There you go, MaryAnne. Thanks for the tip and good luck to your troop.
    Use a PIC microcontroller to replace a 555

    Speaking of circuits, Nuts and Volts has been running a series of articles
    on how to use a PIC microcontroller in place of a 555 timer chip. Heres how
    the first article in the series compares the two:

    Some of the advantages of this implementation as compared to a 555 or 556

    No capacitors
    Very linear response for pulse width
    Delayed pulse capability independent of the pulse width
    Independent control of pulse width and off-time in astable operation
    Very wide range of pulse width and off-time/delay
    Output pulse width is independent of the triggering pulse width

    Some disadvantages:

    Shortest trigger to output delay is about 1 µs
    Shortest pulse is about 3.3 µs
    Longer minimum time between triggers due to reading the ADC
    (analog-to-digital converter) and other processing
    Pulse width and delay use the same range

    Some advantages of the 555:

    Lower cost
    Very low delay time between the trigger and the output pulse
    Narrower pulses possible: <500 ns

    As of this writing, these are the approximate prices for single pieces:

    PIC12F1572 (DIP and SOIC) = $0.60
    NE555PSR (SOIC) = $0.37
    NE556DR (DIP) = $0.45
    CSS555 (SOIC) = $1.55

    HF sports net?

    On the subreddit /r/amateurradio, someone asked if there were any HF sports nets. I dont know of any, but I think something like that might be fun. If
    you known of any, please leave a comment.

    The post Random stuff: Circuits for kids, replace a 555 with a PIC microcontroller, HF sports net appeared first on KB6NUs Ham Radio Blog.

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