■ WITH RUSSELL KINCAID
In this column, I answer questions about all
aspects of electronics, including computer
hardware, software, circuits, electronic theory,
troubleshooting, and anything else of interest
to the hobbyist. Feel free to participate with
your questions, comments, or suggestions.
Send all questions and comments to:
Join us as we delve into the
basics of electronics as applied
to every day problems, like:
PICAXE or PIC? ✓
● Game Show Lockout
GAME SHOW LOCKOUT
QI saw a comment in a forum about a game show lock-out and was wondering if you had a
schematic or description of the circuit
I could use. I only need a two person
— Michael Hickmon
AI answered a similar question in my very first column, May 2007, page 29, but that was more
complex than what you need. This
solution is adapted from a Pinewood
Derby design I did many years
■ FIGURE 1
ago. In Figure 1, the flip-flops are
initially reset by the game master so
the NOT-Q outputs are high. When
contestant A or B presses his switch,
the Q output goes high and the
NOT_Q output goes low, lighting the
LED and sounding the buzzer. I
thought it would be annoying for the
buzzer to be sounding until reset, so
I put in an R-C which will allow the
buzzer to sound for about one
second, until the capacitor charges
up. IC4 is an inverted OR gate; when
any input goes low, the output goes
high. I used 74AC logic because it
has high output current capability
and paralleled the outputs of IC4
for up to 100 mA drive.
The parts list is Figure 2; those
are all Mouser part numbers.
QI wish to step up from the 555s, etc., to micro-controllers for projects as found in
Smiley’s Workshop, PICAXE Primer,
Getting Started with PICs, and others
found in N & V. My questions are: 1.
Would you share your pros and cons
on microcontrollers by AVR vs.
PICAXE vs. Microchip’s PIC line? 2.
What devices do I need to program
with a computer? 3. What devices do I
need to program without a computer?
4. Now that I have the car, where can
I get driving instructions?
I am leaning toward
the PIC line because of
availability and price.
— Weldon Thorp
AI will answer your questions in reverse: 4. Not knowing
where you are, I can’t
answer that. 3. I don’t
want to think about how
you would program
without a computer. 2.
You could program in
assembly code which is
converted to hex code
that the micro understands
or, more likely, you would
program in a higher level
language such as C or