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- CIRCUIT FORMS DIVIDE BY
1.5 COUNTER
Two inexpensive ICs divide a TTL clock signal by 1.5. By following the circuit with
another flip/flop, you could also generate a divide by three function.
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- DARKROOM CAMERA SHUTTER
TIMER
This circuit was designed to control a film exposure shutter for a darkroom. It has
8 time steps ranging from 0.35 seconds to 4 seconds. It is activated by a foot
switch and draws power from an external 12 volt DC supply.
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- HONEYBEE COUNTER
I designed a circuit similar to this one a long time ago to help a beekeeper count
the number of bees going into or out of a hive. The low power circuit uses a slotted
opto-sensor to detect the passing bees. The circuit advances an electronic counting
module whenever a honeybee passes through the sensor. The device only counts the
number of bees going through the sensor. A different circuit would be needed to
count the number of bees only going out or only coming into the hive.
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- LONG PERIOD COMPUTER
WATCH DOG TIMER
This circuit uses a simple 4060 IC oscillator/timer which is reset periodically by a
computer. Should the computer fail to send a pulse, the output changes state. The
time can easily be set from seconds to hours.
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- On/Off Flip/flop
Circuit with Automatic Timeout
This circuit is ideal when a device needs to be turned on and off with a single
pushbutton switch, but also needs to turn itself off after some period of time. With
the components shown, the output will stay on for only about 20 seconds.
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Poor Man’s Digital Counter Using Pedometer
There are many
occasions when you may want to count something electronically. Perhaps it is
car traffic on a street or items moving down an assembly line. It might be the
number of times a machine is activated or maybe you want to count the number of
people entering doorway. Commercial counting modules do exist but if you want
to use something cheaper, you can modify a pedometer to do much the same thing....
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Poor Man's Timer
Often during testing of certain equipment and components, you would like to keep
track of the elapsed time in hours, minutes and seconds. There are some nice
commercial digital timers and counters available for just this sort of application.
However, although it may not be as accurate, there is a cheaper way to go. I’m
sure many of you have some old wrist watches or battery powered dial faced alarm
clocks collecting dust in some drawer.
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