Body heat detector
altec3
Posts: 3
Ive been working on making a turret out of an airsoft gun for some time. I've decided that making a device that would detect body heat would work best. The problem is the only thing that i have found that will work is this schematic. My plan was to interface it into my Basic stamp to control tracking/firing. I was hoping to someway avoid the cost and time with building this, so if anyone has any ideas on how to use the stamp to process most of this instead of electronics i would greatly appreciate it, Thanks.
2492 x 2012 - 82K
Comments
www.hvwtech.com/products_view.asp?CatID=114&SubCatID=186&SubSubCatID=0&ProductID=270
these guys sell Passive IR motion detectors!
The lens cover on them offers a wider view of things....but if you didn't want to spend the time on a schematic that may or maynot work (some of them don't) then you could spend the time finding a lens or a mask (to block out the unwanted lens area) and use this.
This sensor only gives a TTL logic level for when it sees motion....no quantitative values!
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
·
Steve
"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."
Here is a raw (plain, TO-5 cased) dual IR sensor element which might be easier to turret mount than some of the larger, encased PIR Modules which may be available:
http://www.mpja.com/directview.asp?product=7250+MI
Regards,
Bruce Bates
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
·1+1=10
i have been looking into this one, has a narrow field of view 15 degrees, which is good for localized detection. And also has a comparator circuit, which would be good for direction of movement, and to filter out false readings. It might be better in your application, as you will only want to detect motion in the area that the gun is pointing. I can't get the specs from the site on it, as the download page does not work for their sensors. So, i am not sure of the output or the cycle time. Looks interesting though.
kelvin
It you want to detect stationary temperatures, a thermopile is required.
These are used in electric ear thermometers. I suspect you would need pairs to do comparision.
The two look very similar and I just purchased two Pryoelectrics by mistake [noparse][[/noparse]they have 3 wires, the thermopiles have 2 or 4].
I am trying to apply them to detecting the horizon in R/C Airplanes to dampen roll during landing.
It looks to me like i could use two Proelectrics if they are placed on the vertical axis.
I got a whole package of lens with them, but the documentation is all in Chinese. Oh well....
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
I suspect there may be a bit of confusion here regarding the various types of heat, flame and infrared detectors that are available. It IS INDEED confusing!
The PIR detector (passive infrared) often is linked with a motion sensing component, and used as a method to detect live (human or animal) body movement. Whether they have a motion component or not, they generally have 3 wires. One is positive voltage, one is negative voltage, and the third is the "sense" wire, which is active when the sensor detects what it's supposed to detect. PIR detectors often have lenses to limit their visibility. They are often used in alarm systems.
An ordinary IR sensor detects just that. The presense (within its scope of vision) of any infrared energy. If it's set up as a detector, it may have 2, 3 or 4 wires, depending on the output and how the manufacturer has designed it. A plain IR sensor, more often than not, has 2 or 3 wires. Often these may use thermisters to measure the IR energy. generally these are quantitative devices.
A thermopile, which is generally used to measure high temperatures, or temperature from a great distance, usually have 4 wires, and sometimes more. they are sometimes used in gas furnace applications. They are a category all unto themselves.
Pyroelectric sensors or detectors are generally used specifically to seek or sense a flame, not just infrared energy or heat. Pyroelectric sensors can often be found in gas appliances for obvious safety reasons. Firefighting robots also use a pyroelectric sensor to find the target candle flame.
Here is a fairly good reference on some of these sensors and detectors as offered by one company which manufacturers some of them:
http://www.servo.com/elecpd1.htm
There are even more varieties than this, but these are the basic ones you generally see.
Regards,
Bruce Bates
Your schematic really optimizes the ability to recognize direction.· I suspect it you calculate the delay, you can recognize laterial speed too.
After all, they can and do sense movements of warm blooded animals [noparse][[/noparse]and other warm objects] it and about an area [noparse][[/noparse]or robot].
I imagne they can trigger a voice to either say "Hello", "Goodbye" or offer a challenge. They can also turn on or call attention to monitoring video cameras.
And, they have a much longer range [noparse][[/noparse]mine are rated for 30 meters] than Ultrasonic or IR proximity sensors. In combination, you really begin to create a robot that is 'aware' of what is around it.
The detection of horizon in the roll axis of a modle airplane is obviously a bit of a 'cheat'. The thermopiles work fine. But, I have trouble buying them here. The cost $16USD from Digikey, but I can get PIRs for $3USD locally.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
I added a window compairator to the output (simple opamp) of the above and it will detect me at a distance of 30 standing still.· I have it interfaced with a basic stamp which inturn controls the panning motion of the video camera mounted just below the "eyes" in the picture of ROBO CHILD at the left.· It will detect me and stop the pan of the camera every time.· Light bulbs, computer screens, just about any heat source including my warm drill press motor. (Took me a while to figure out why the camera kept stopping on my drill press, and the EMIC telling me that it had detected a heat source?)
If the device is mounted on a stationary device (doesn't move), it can detect left to right and right to left movement across its field of view.
Anyway, hope this helps...
Deno
Why don't you just purchase one pyroelectric sensor and mount it on a rotatable platform using an R/C servo? This is often done with echo-location (sonar) units as well as other expensive sensors/detectors to reduce the cost incurred when using multiple sensors.
Regards,
Bruce Bates
Post Edited (Bruce Bates) : 12/11/2006 10:53:07 AM GMT