Basic stamp and darlingtons
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Posts: 46,084
>A high from the Stamp turns the Darlington on -output collector goes low.
>Why in the world would you want a 2803 output fed back to the Stamp.
I probably wasn't clear. I'm using a Darlington array. Some of the inputs of
the array are to be driven by stamp outputs. One of the inputs, though, is
connected to a water sensor, and the output of that is to be connected to a
stamp input.
But I didn't realize the Darlington was inverting (I've never used one), I
was just hoping to avoid putting another transistor on the board to sense
the water level, since I had some unused darlingtons just sitting there in
the array. I mean, it would have saved a whole 0.45$ or so. :-)
Sounds like I'm just better off getting a plain old PNP transistor at 5v,
pulling
the collector output down with a 10K to (-), and feeding it through a 5K or
so to the basic stamp input... is that a common approach?
>Why in the world would you want a 2803 output fed back to the Stamp.
I probably wasn't clear. I'm using a Darlington array. Some of the inputs of
the array are to be driven by stamp outputs. One of the inputs, though, is
connected to a water sensor, and the output of that is to be connected to a
stamp input.
But I didn't realize the Darlington was inverting (I've never used one), I
was just hoping to avoid putting another transistor on the board to sense
the water level, since I had some unused darlingtons just sitting there in
the array. I mean, it would have saved a whole 0.45$ or so. :-)
Sounds like I'm just better off getting a plain old PNP transistor at 5v,
pulling
the collector output down with a 10K to (-), and feeding it through a 5K or
so to the basic stamp input... is that a common approach?
Comments
scott@m... writes:
> I probably wasn't clear. I'm using a Darlington array. Some of the inputs
> of
> the array are to be driven by stamp outputs. One of the inputs, though, is
> connected to a water sensor, and the output of that is to be connected to a
> stamp input.
>
Any sensor has to have some kind of an output that can be recognized. If the
water sensor outputs a voltage then it can be measured with an ADC, and then
the Stamp can do something based on the ADC reading. If the water sensor has
a purely resistive out put, then you would have to connect one side of it to
5VDC via a resistor that is at least equal to the max resistance of the water
sensor, but not lesss than 5K. Then you connect your ADC to the top of the
water sensor and read the voltage as the water level changes.
Remember, the output of your sensor is essentially analog, so you must
convert it to a digital form before it can be used by the Stamp.
Sid
[noparse][[/noparse]Non-text portions of this message have been removed]
jim
http://www.geocities.com/jimforkin2003/
Original Message
From: Scott [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=czL7ORc7c5aai0Q8TR4KCEqTVabv-S5ZfHqGsXs1G1tWY3JC3kOr3jmBCrzpK_aeINTg3j-6mQ]scott@m...[/url
Sent: Tuesday, November 25, 2003 2:18 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Basic stamp and darlingtons
>A high from the Stamp turns the Darlington on -output collector goes low.
>Why in the world would you want a 2803 output fed back to the Stamp.
I probably wasn't clear. I'm using a Darlington array. Some of the inputs of
the array are to be driven by stamp outputs. One of the inputs, though, is
connected to a water sensor, and the output of that is to be connected to a
stamp input.
But I didn't realize the Darlington was inverting (I've never used one), I
was just hoping to avoid putting another transistor on the board to sense
the water level, since I had some unused darlingtons just sitting there in
the array. I mean, it would have saved a whole 0.45$ or so. :-)
Sounds like I'm just better off getting a plain old PNP transistor at 5v,
pulling
the collector output down with a 10K to (-), and feeding it through a 5K or
so to the basic stamp input... is that a common approach?
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