cheap clock suggestion
Archiver
Posts: 46,084
Quite a number of times on this list I've seen
requests for an accurate timing source to use
with the Basic Stamp -
If you take the guts out of a "quartz" mechanical
clock which uses a crystal and 1.5 volt battery
you have a very accurate 1 pps source [noparse][[/noparse]substitute
a resistor for the solenoid second hand driver].
Put that pulse into a flip-flop and you have a
squarewave with a .5 Hz frequency which can be
sensed in a loop reading the Stamp pin connected
to this .5 Hz squarewave.
A detail - level translation from the 1.5v clock
to the 5V IC flip-flop which connects to stamp pin
can be accomplished by a transistor [noparse][[/noparse]NPN collector to
10K r to +5v, emitter to common, base to 1K resistor
to .5 Hz positive pulse - collector goes also to
flip-flop clock input pin].
These clocks are often found in wastebaskets [noparse][[/noparse]dead
battery!], thrift stores and yard sales for about $1.
Hope this suggestion is of use to some of you... you're
a wonderful group of old hands and new enthusiasts - thanks
for all the interesting posts!
________________________________________________________________
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requests for an accurate timing source to use
with the Basic Stamp -
If you take the guts out of a "quartz" mechanical
clock which uses a crystal and 1.5 volt battery
you have a very accurate 1 pps source [noparse][[/noparse]substitute
a resistor for the solenoid second hand driver].
Put that pulse into a flip-flop and you have a
squarewave with a .5 Hz frequency which can be
sensed in a loop reading the Stamp pin connected
to this .5 Hz squarewave.
A detail - level translation from the 1.5v clock
to the 5V IC flip-flop which connects to stamp pin
can be accomplished by a transistor [noparse][[/noparse]NPN collector to
10K r to +5v, emitter to common, base to 1K resistor
to .5 Hz positive pulse - collector goes also to
flip-flop clock input pin].
These clocks are often found in wastebaskets [noparse][[/noparse]dead
battery!], thrift stores and yard sales for about $1.
Hope this suggestion is of use to some of you... you're
a wonderful group of old hands and new enthusiasts - thanks
for all the interesting posts!
________________________________________________________________
YOU'RE PAYING TOO MUCH FOR THE INTERNET!
Juno now offers FREE Internet Access!
Try it today - there's no risk! For your FREE software, visit:
http://dl.www.juno.com/get/tagj.
Comments
waiting for this mod.
s promena, thanks.
I too enjoy this board to no end!
Trouble is I get very little time to enjoy it, arrrgh!
Mark
Original Message
From: s premena <premzee@j...>
To: basicstamps@egroups.com <basicstamps@egroups.com>
Date: Monday, October 23, 2000 1:28 PM
Subject: [noparse][[/noparse]basicstamps] cheap clock suggestion
>Quite a number of times on this list I've seen
>requests for an accurate timing source to use
>with the Basic Stamp -
>
>If you take the guts out of a "quartz" mechanical
>clock which uses a crystal and 1.5 volt battery
>you have a very accurate 1 pps source [noparse][[/noparse]substitute
>a resistor for the solenoid second hand driver].
>Put that pulse into a flip-flop and you have a
>squarewave with a .5 Hz frequency which can be
>sensed in a loop reading the Stamp pin connected
>to this .5 Hz squarewave.
>
>A detail - level translation from the 1.5v clock
>to the 5V IC flip-flop which connects to stamp pin
>can be accomplished by a transistor [noparse][[/noparse]NPN collector to
>10K r to +5v, emitter to common, base to 1K resistor
>to .5 Hz positive pulse - collector goes also to
>flip-flop clock input pin].
>
>These clocks are often found in wastebaskets [noparse][[/noparse]dead
>battery!], thrift stores and yard sales for about $1.
>
>Hope this suggestion is of use to some of you... you're
>a wonderful group of old hands and new enthusiasts - thanks
>for all the interesting posts!
>
>________________________________________________________________
>YOU'RE PAYING TOO MUCH FOR THE INTERNET!
>Juno now offers FREE Internet Access!
>Try it today - there's no risk! For your FREE software, visit:
>http://dl.www.juno.com/get/tagj.
>
>
>
>