How to convert a 5k pot into a 555 timer then into stamp
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my question is regaurding on how to use a 5k pot pluged into a 555
timer then have the gernated single go into input on a stamp 2.... my
idea is to have the pot's resolution be from 1~4 or even 1~8 steps on
the roation of the pot... the pot is off a car thottle body's sensor
and its roataion is probley 80 some degrees so the varible resistance
is probley anywhere from few hunderes of a ohm at nutral to 3 or 4
kilo ohms at full speed ... i was thinking of useing a 555 timer to
generate a value into the stamp that will reigster in only a
resolution of a few steps such as 4 or 8 steps of resolution (if any
of this makes sence, first timer hear... heh) the appilcation im
useing this on is time critial, my window of time for the stamp to
react from the value of the thottle postion and raotation of the
engine is a window of 4~5 milo sencods.... maybe i neeed a faster
chip? to bad stamps dont come with a pentium 4 3.0 gig cpu built on
them heh...
Sean...
timer then have the gernated single go into input on a stamp 2.... my
idea is to have the pot's resolution be from 1~4 or even 1~8 steps on
the roation of the pot... the pot is off a car thottle body's sensor
and its roataion is probley 80 some degrees so the varible resistance
is probley anywhere from few hunderes of a ohm at nutral to 3 or 4
kilo ohms at full speed ... i was thinking of useing a 555 timer to
generate a value into the stamp that will reigster in only a
resolution of a few steps such as 4 or 8 steps of resolution (if any
of this makes sence, first timer hear... heh) the appilcation im
useing this on is time critial, my window of time for the stamp to
react from the value of the thottle postion and raotation of the
engine is a window of 4~5 milo sencods.... maybe i neeed a faster
chip? to bad stamps dont come with a pentium 4 3.0 gig cpu built on
them heh...
Sean...
Comments
There are a number of digital controlled pots in the market primarily
used for audio application. There are not cheap. I don't keep that in
my database. You can do a search on the net. But for controlling timer
like 555 just use the good old multiplexer 4067 or 4097. I used it
with and optical isolator using LDR to interface to an AC circuit. I
could get as low as 200 ohms if I parallel the LDR. The maximum
resistance was 10M ohms. Select the stock of LDR that suits you. The
LDR replaced the original pot on the AC circuit. If you use the 4097
which is a dual 8 to 1 multiplexer, you could use the other half to
drive LEDs for indication of your steps. You need a decade/binary
counter at least to drive the multiplexer. For the codes just use a
FOR-NEXT loop to step it up. 1 PIN to clock the counter and one more
PIN to reset it.
Cheers,
- Johari
--- In basicstamps@yahoogroups.com, "djrevolution99"
<djrevolution99@y...> wrote:
> my question is regaurding on how to use a 5k pot pluged into a 555
> timer then have the gernated single go into input on a stamp 2.... my
> idea is to have the pot's resolution be from 1~4 or even 1~8 steps on
> the roation of the pot... the pot is off a car thottle body's sensor
> and its roataion is probley 80 some degrees so the varible resistance
> is probley anywhere from few hunderes of a ohm at nutral to 3 or 4
> kilo ohms at full speed ... i was thinking of useing a 555 timer to
> generate a value into the stamp that will reigster in only a
> resolution of a few steps such as 4 or 8 steps of resolution (if any
> of this makes sence, first timer hear... heh) the appilcation im
> useing this on is time critial, my window of time for the stamp to
> react from the value of the thottle postion and raotation of the
> engine is a window of 4~5 milo sencods.... maybe i neeed a faster
> chip? to bad stamps dont come with a pentium 4 3.0 gig cpu built on
> them heh...
>
>
> Sean...
<djrevolution99@y...> wrote:
> my question is regaurding on how to use a 5k pot pluged into a 555
> timer then have the gernated single go into input on a stamp 2....
my
> idea is to have the pot's resolution be from 1~4 or even 1~8 steps
on
> the roation of the pot... the pot is off a car thottle body's
sensor
> and its roataion is probley 80 some degrees so the varible
resistance
> is probley anywhere from few hunderes of a ohm at nutral to 3 or 4
> kilo ohms at full speed ... i was thinking of useing a 555 timer to
> generate a value into the stamp that will reigster in only a
> resolution of a few steps such as 4 or 8 steps of resolution (if
any
> of this makes sence, first timer hear... heh) the appilcation im
> useing this on is time critial, my window of time for the stamp to
> react from the value of the thottle postion and raotation of the
> engine is a window of 4~5 milo sencods.... maybe i neeed a faster
> chip? to bad stamps dont come with a pentium 4 3.0 gig cpu built on
> them heh...
If I understand, you want a pot to feed a 555.
The timer to send out a series of pulses that represent the
approximate analog value of the pot (cheap ADC).
The Stamp to read the pulse train (PULSEIN) from the 555 as opposed
to RC Time.
Calculate something and probably do an output and other processing,
in 4-5 milli Seconds or 4-5 Khertz.
Is what you are controlling going to change the sensor position ?
ie: will you be doing a feedback control loop ? That would indicate
you want to add some control algorithm to the Stamp.
In re-reading your post, it seems that all you need to do is google
555 timer and get a link that lists the interaction of the resistors
and cap for a 555. Actually, I think there is a small program that
allows you to put in time values and it lists the resistors and cap.
you should be able to plug 5k in for one value and calculate the rest.
Dave