Water temperature, LED output

Archiver

Folks,

I'm new to Stamps, and have a project that seems well suited to
learning about them a bit more.

I need to read water temperature, and then vary the intensity of an
LED based on the value. To complicate matters, I need to light 3
different color LEDs representing discrete temperature bands. The
LEDs will be on discretely - that is to say one at a time. (I only
need to consider temperatures in the range from +35 F to +135 F.

While I think I have a pretty good idea of how to do this, I'm sure
there are people who have been down this road, and I'd love to get
some suggestions.

All ideas welcomed.

Adam

Archiver

--- In basicstamps@yahoogroups.com, "sunvalleyhouse"
<sunvalleyhouse@y...> wrote:
> Folks,
>
> I'm new to Stamps, and have a project that seems well suited to
> learning about them a bit more.
>
> I need to read water temperature, and then vary the intensity of an
> LED based on the value. To complicate matters, I need to light 3
> different color LEDs representing discrete temperature bands. The
> LEDs will be on discretely - that is to say one at a time. (I only
> need to consider temperatures in the range from +35 F to +135 F.
>
> While I think I have a pretty good idea of how to do this, I'm sure
> there are people who have been down this road, and I'd love to get
> some suggestions.
>
> All ideas welcomed.
>
> Adam


Hi Adam,

you don't say how accurate any of the bands or points need to be so
If you use a temperature IC you will 8 bit or better. that would be
on the order of 1/4 ot 1/2 a degree resolution. I think that it will
be hard to get more accurate anyway.

There are app notes on how to wire and program for these chips.

From there, just read on how to light the LED's and you should be
blinking away in short order.

As for the temperature sensor, you can put it in a tube and fill it
with liquid electrical tape or possibley silicone or some non-
conductive caulk.

If you want to get fancy, you can make the led's blink, the first for
100's so it would blink or not. the second for 10's and the last for
1's. That way you can use the LED's to report single point
termperatures.

You could even use one to blink in succession to report the actual
temperature.

Dave

Archiver

--- sunvalleyhouse <sunvalleyhouse@y...> wrote:
> Folks,
>
> I need to read water temperature, and then vary the
intensity of an LED based on the value. To complicate
matters, I need to light 3 different color LEDs
representing discrete temperature bands.

When I have used circuits that vary the intensity of
an LED I have been very dissapointed that are not as
noticable as when using a regular bulb. I would
suggest an LED ladder ie: 1 LED on for low, 2 LEDs on
for mid range 3 LEDS on for high, might give a more
satisfactory results.

For what it is worth, Nigel




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Archiver

Dave:

I don't need a very accurate resolution on the temperature sensing.
If I can note water temperature changes on the order of 2-4 degrees
over a period of 5-10 seconds, I'll be fine.

As to the temperature sensing chips, I looked at some of the app
notes, but it seemed as though the sensing actually took place as
part of the chip. I was thinking that a thermistor might be better
for me as I need a physically small device that will fit in a nozzle
of about 3/4" diameter and not occlude the water flow. It needs to
be able to exist in the water flow and not corrode or short. If the
temp chips use an offboard set of inputs that would be ideal as you
are correct, the interfaces are simple.

I appreciate the assistance, and particularly everyone's thoughts on
the efficacy of dimming the LED. I may try flashing it to see what
the light output looks like at various duty cycles.

Adam
>
>
> Hi Adam,
>
> you don't say how accurate any of the bands or points need to be
so
> If you use a temperature IC you will 8 bit or better. that would
be
> on the order of 1/4 ot 1/2 a degree resolution. I think that it
will
> be hard to get more accurate anyway.
>
> There are app notes on how to wire and program for these chips.
>
> From there, just read on how to light the LED's and you should be
> blinking away in short order.
>
> As for the temperature sensor, you can put it in a tube and fill
it
> with liquid electrical tape or possibley silicone or some non-
> conductive caulk.
>
> If you want to get fancy, you can make the led's blink, the first
for
> 100's so it would blink or not. the second for 10's and the last
for
> 1's. That way you can use the LED's to report single point
> termperatures.
>
> You could even use one to blink in succession to report the actual
> temperature.
>
> Dave

Archiver

if all you need is +35 F -- +135 F thats a 100 F range. One solution would
be equally divided ranges and brightness levels
so for 3 LED's that would be divided up into 3 even ranges. with each range
further divided up into 3 brightness level ranges. kinda like below

LED1 --- (+35 F - +68 F)
Brightness Level 1 --- (+35 F - +45 F)
Brightness Level 2 --- (+46 F - +56 F)
Brightness Level 3 --- (+57 F - +68 F)

LED2 --- (+69 F - +101 F)
Brightness Level 1 --- (+69 F - +79 F)
Brightness Level 2 --- (+80 F - +90 F)
Brightness Level 3 --- (+91 F - +101 F)

LED3 --- (+102 F - +135 F)
Brightness Level 1 --- (+102 F - +112 F)
Brightness Level 2 --- (+113 F - +123 F)
Brightness Level 3 --- (+124 F - +135 F)

As another option, like someone said, you could have them blink as
temperature range indicators. maybe something like Level 1 : no blink,
Level 2 : blink 1 Hz, Level 3 : blink .5 Hz . You could even
use tri-color LED's to indicate temp range. the possibilities are almost
endless. This is an interesting project. I would like to here the outcome
of it. use your imagination and who knows what you can come up with.

<boing!> you just gave me an idea. could be used as a temperature monitor
for a swimming pool. My current method is the ole toe-in water. But the
water temperature gets colder the deeper you go down in the water. So it
feels warm on top but jump in and Oooaaaaahhhh!!
This 3 varying brightness LED method seems like it should work. Picture
this, its a 24' above ground pool with 3 layers of rope lighting around the
pool. Each layer will be blinking at a different rate. It will add a cool
effect to the pool as well as serve some useful purpose. Ummm sounds like a
project for a BS1, a few triacs and baba-bing! a useful conversation piece
this summer at the pool.

Daryl


At 11:25 PM 5/29/2004, you wrote:
>Folks,
>
>I'm new to Stamps, and have a project that seems well suited to
>learning about them a bit more.
>
>I need to read water temperature, and then vary the intensity of an
>LED based on the value. To complicate matters, I need to light 3
>different color LEDs representing discrete temperature bands. The
>LEDs will be on discretely - that is to say one at a time. (I only
>need to consider temperatures in the range from +35 F to +135 F.
>
>While I think I have a pretty good idea of how to do this, I'm sure
>there are people who have been down this road, and I'd love to get
>some suggestions.
>
>All ideas welcomed.
>
>Adam
>
>
>
>
>
>
>To UNSUBSCRIBE, just send mail to:
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>
>
>

Archiver

> Each layer will be blinking at a different rate. It will add a cool
> effect to the pool as well as serve some useful purpose. Ummm
sounds like a
> project for a BS1, a few triacs and baba-bing! a useful
conversation piece
> this summer at the pool.


You could have a floating jellyfish with a long string to test teh
water termperature. the jellyfish part could have LED's that blinked
in some fashion.

Maouser has transluscent enclosures of clear, blue and other colors,
so you could make the thing water tight.

Dave

Archiver

Wow! Dave, floating jellyfish, ummmm or maybe a floating frog on a lily
pad. That would make a nice project. Are you sure don't work in
marketing? [noparse]:)[/noparse] now that would be useful. yep, a water tight enclosure would
be a good thing. while were on the subject, was it you or someone
else, that mention about the idea of putting a temperature sensor in a
tube sealed with silicon? Good idea. that would be perfect for the DS1820
temp sensor. the 1-wire sensor works well with BS-1, admit more coding tho




At 07:44 PM 5/30/2004, you wrote:
> > Each layer will be blinking at a different rate. It will add a cool
> > effect to the pool as well as serve some useful purpose. Ummm
>sounds like a
> > project for a BS1, a few triacs and baba-bing! a useful
>conversation piece
> > this summer at the pool.
>
>
>You could have a floating jellyfish with a long string to test teh
>water termperature. the jellyfish part could have LED's that blinked
>in some fashion.
>
>Maouser has transluscent enclosures of clear, blue and other colors,
>so you could make the thing water tight.
>
>Dave
>
>
>
>
>
>
>
>
>
>
>To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
>from the same email address that you subscribed. Text in the Subject and
>Body of the message will be ignored.
>
>Yahoo! Groups Links
>
>
>
>