QUESTIONS & ANSWERS
counters (IC4, IC3, and IC7) have reached zero,
IC9A clocks the quarter counter, IC10. When the
quarter count reaches 5, IC13A decodes that
number, resets all the counters, and stops the
clock via D1.
There is no power-up reset so the game
master will have to press the “new game” button
to start. The new game button can be pressed at
any time to terminate a game and start over. IC11
is a 555 oscillator running at 60 Hz to drive the
If you build this, let me know how it turns out.
The LCD runs on five volts, but there is no
maximum specified so I think it will work on nine
volts. I did not breadboard this, so if anyone finds
a flaw in my logic, please let me know.
BLINKING TAILLIGHT REVISITED
QIn addition to that blinking taillight brake mentioned in the June ‘ 10 Q&A, how about increasing the blink rate and light intensity in proportion to the car’s
Perhaps using one of those accelerator
sensing chips I see advertised and an
additional/optional circuit for external
super bright LEDs?
A timer/op-amp hardware
solution seems possible (well, for
someone much cleverer than I it
might seem possible!!).
— Brian Stoller
AIncreasing the blink rate with deceleration is a good idea. However, even though the acceleration IC
is cheap, the development hardware
and software is expensive, so I won’t
Besides, I subscribe to the KISS
principle and a rheostat with a
weighted knob will do the trick.
Replace R3 in Figure 5 of the June
issue with a 50K rheostat
(potentiometer) oriented so that
the weight swings forward and
connected to reduce the resistance.
You can rotate the rheostat to get the
desired resting blink rate.
A similar, lower resistance
rheostat in series with the taillight
could be used to change the
brightness; although the resting
brightness would be reduced. NV
FRONT PANELS & ENCLOSURES
Customized front panels can be easily
designed with our free software
Front Panel Designer
New Version 4.0
New functions include dxf import
for inner and outer shapes. Linux,
Windows, and Mac OS X compatible.
September 2010 27