Re: IR Temperature Sensor
- From: N0Spam@xxxxxxxxxxx (Bob Masta)
- Date: Thu, 05 Mar 2009 13:31:57 GMT
On Wed, 4 Mar 2009 21:04:07 -0800 (PST),
tranerm@xxxxxxxxx wrote:
On Mar 4, 11:19=A0am, Nemo <P...@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
wrote:
tranerm asks
I am attempting to construct a temperature sensor that will activate
several relays when the thermometer senses temperatures above 150
degrees Celsius, or ignition point for decayed wood. Unfortunately I
have only been able to find this plan online, which has far more
features than I need.
http://www.electronics-lab.com/projects/test/023/index.html
If anyone knows of a circuit diagram that would be more to my needs or
has suggestions of any sort, I would be extremely grateful.
If you base your circuit on an IR sensor you will have a lot of
problems, because IR is everywhere. You'll get false positives from
normal lights and even clever circuits which try to auto-adjust for the
average background level can get fooled by, say, a cloud passing across
the sun. Also - how are you going to calibrate it? And protect the high
gain circuitry from RF pickup when someone uses a mobile phone below it?
May I suggest a simpler approach like this:
http://uk.farnell.com/honest-well/t23a150bsr2-15/thermal-switch-nc-15...
dp/1006849
this kind of component, a "thermal switch", is widely available. I used
one recently partly because I noticed this particular shape is some kind
of standard, so even if that manufacturer goes bust Honeywell and some
other bunch will still stock them.
The main problem with this item is that it is normally closed. But if
you're happy to burn a bit of power and continuously power a relay
(20mA?) that's OK. An IR circuit would burn a bit of power anyhow.
--
Nemo
I will be runninf it off a a wall wart so power won't be a problem,
but the interference probably would be. I am trying to build a small
'turret' that will first seek brightness (in a dark room, so for
example, a candle) and then when the IR sensor is facing it if the IR
sensor detects heat above a certain level, activate a series of
relays. One or two of these will shut down the motors moving the
turret, and another will activate a small pump that will squirt water,
extinguishing the flame. From there, if possible I would like it to
seek another target if the detcts temp below a certain level. (however
this is purely an extra) I want to be able to switch the locations of
the candle, so I can't reallly just run temp relays back and forth
either, unfortunately. Thank you incredibly for your help(:
Except for the wall-wart, your description sounds
almost exactly like an entry for the "Firefighting
Robot" competition. The robot has to negotiate a
"house" to find the room with the candle, and put
it out. You might want to check on what others
have done, and the problems encountered.
In the competition, the "house" is a small maze of
rooms with no roof, in a big auditorium that has
overhead fluorescent lights that can interfere
with the sensors. There were articles in Circuit
Cellar several years ago, but I don't recall what
the best solution turned out to be.
Best regards,
Bob Masta
DAQARTA v4.51
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
FREE Signal Generator
Science with your sound card!
.
- References:
- IR Temperature Sensor
- From: tranerm
- Re: IR Temperature Sensor
- From: Nemo
- Re: IR Temperature Sensor
- From: tranerm
- IR Temperature Sensor
- Prev by Date: Re: What will happen if an analog signal is passed through a DAC?
- Next by Date: Re: Problems about pic thermometer
- Previous by thread: Re: IR Temperature Sensor
- Next by thread: Footwear (paypal payment)(www.king-trade.cn )
- Index(es):
Relevant Pages
|
