Society of Robots - Robot Forum
Electronics => Electronics => Topic started by: Joker94 on August 24, 2009, 01:05:39 AM
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What do people think of passive innfared sensors. In particular the two at the top of the page,the unmounted ones.
Has any body used these and have an opinion, I have not go a plan to use them just want to see what people think. And or if it is worth getting one or two and experimenting witht them on my robot.
http://www.futurlec.com.au/PIR_Sensors.jsp (http://www.futurlec.com.au/PIR_Sensors.jsp)
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What do people think of passive innfared sensors. In particular the two at the top of the page,the unmounted ones.
Has any body used these and have an opinion, I have not go a plan to use them just want to see what people think. And or if it is worth getting one or two and experimenting witht them on my robot.
http://www.futurlec.com.au/PIR_Sensors.jsp (http://www.futurlec.com.au/PIR_Sensors.jsp)
LadyADA published a tutorial about PIR just a few days ago:
http://www.ladyada.net/learn/sensors/pir.html
Now concerning using it on a robot, I don't think it would work. PIR detect motion of IR emitting bodies. The problem is, your robot itself is moving! the sensor will detect motion all the time!
Chelmi.
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thanks chelmi. I was having the same thoughts as you , the reason i posted to double check other people oppinions.
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worse thing about PIR is that it only detects changes in heat, so if its pointing at a fire that wouldn't be a change in heat, since the heat remains the same.
Well I guess thats not technically true since the definition of heat is transfer of energy due to a difference in temperature, so the fire, assuming it and its area were at a constant temperature, wouldn't have heat... but i digress....
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This is the reason I opted for the most expensive sensor on my robot: Thermopile Array. This sensor detects temperature of warm objects, including humans, pets, TVs, monitors, PCs, anything that is warmer than ambient temperature. And it has 8 sensors in one, with a total of 41 degrees angle. Simple I2C interface, you get ambient plus 8 temperature readings. Also you can connect a servo to it to pan (or tilt) the sensor. The cheapest place I found this sensor is at HVWtech: http://www.hvwtech.com/products_view.asp?ProductID=947 (http://www.hvwtech.com/products_view.asp?ProductID=947) for $99.50.
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The only problem is that i don't have $100 to spend on a sensor :(