In my mind, a 555 timer is more difficult to understand as it has a
comparator and flip flop inside amongst more things.
I guess it depends on the opinion of what is easier to understand. In my
mind, relays are easier to understand than logic in chips like that.
For example, you can have a push button discharge a cap. That cap would be
across the windings of a relay. Big cap fed via a resistor. Push the
button and the relay opens until the cap charges back up.
That is a pretty simple timer circuit. t=RC.
If you want to cut down the size of the big cap and obvious short life of
the pushbutton, you can go one step further and put a transistor in the
circuit etc etc. In my mind that is much simpler and easier to understand
than a 555.
However, if you are looking for a simple block diagram understanding, the
555 is the way to go.
I realize that I may not have the ability to look at these things as a kid
would look at them. What is simple to me may not be simple to them and vice
versa.
-----Original Message-----
From: Mark - Myakka Technologies
Sent: Friday, January 09, 2015 10:04 AM
To: Chuck McCown
Subject: Re: [AFMUG] OT - EE help please
Chuck,
I'll be working with the kids again tonight. Hopefully we'll have
time to go in a bit more detail. The 555 is appealing being it can
do many things. We can use it as a timer, we can use it to flash
leds, etc. The kids will only have to learn about the 555, caps and
resistors.
--
Best regards,
Mark mailto:m...@mailmt.com
Myakka Technologies, Inc.
www.MyakkaTech.com
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------
Friday, January 9, 2015, 11:49:02 AM, you wrote:
CM> In mind this is a finite state machine. I would want to see an
exhaustive
CM> state diagram.
CM> The circuit could be made using nothing but relays.
CM> Or it could be made with a single eprom and some caps.
CM> Or transistors and caps.
CM> Or 74xx logic chips like flip flops.
CM> Or a MCU chip or CPU based development board.
CM> I think I could do this with pneumatics too. Perhaps mousetraps and
strings
CM> too.
CM> What happens if someone repeatedly presses just one button or two
buttons?
CM> If someone presses the first button, does it wait forever for someone to
CM> press the second button or is there a timeout. Etc etc etc. State
diagram
CM> would be most helpful.
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