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

Circuits for kids

A reader writes:

I wanted to thank you for putting together your links page. My daughter MaryAnne’s 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!

MaryAnne’s 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 it’s 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
https://www.speedwaymotors.com/Info/All-About-Electronic-Circuits-for-Kids

I’d 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!)

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. Here’s how the first article in the series compares the two:

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

• 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 don’t know of any, but I think something like that might be fun. If you known of any, please leave a comment.