carbon monoxide detector values image
nandiana20
I'm doing this paper on wireless monitoring and I really need to know how sensors basically work and more specifically how temperature ,pressure ,light,radiation, force and toxic gas sensors work. I'm not an electronics student. So an extremely simple explanation would be helpful.
Answer
It is a HUGE field, so you will have to do some web searching. Manufacturers pages are usually good places to find explanatory info.
Temperature:
Thermocouple - makes use of the fact that a junction of 2 different metals produces a voltage difference which varies with temperature.
Thermistor - a resistor whose value changes with temperature. There are 2 types, PTC and NTC, positive / negative temperature coefficient.
Pressure:
Typically you have a silicon membrane with a force sensor (strain gauge) on it. Pressure on one side of the membrane causes it to distort, which causes a change in resistance in the sensor.
Light:
Photodiode - a diode that leaks current according to how much light falls on it.
Light-dependant resistor (LDR) - does what it says!
Radiation:
Ionisation type detectors - basically a gas-filled tube. When a radiation particle strikes a gas atom it creates an ion, or charged atom. An electric field attracts the ion to a plate, where it is detected as a pulse of current.
Scintillation detector - use a crystal that produces a flash of light when struck by a particle. The flas is detected by a light sensor.
Force:
Strain gauge - a thin film of resistive material. Resistance changes when it is flexed.
Force sensing resistor (FSR) - resistance changes when squeezed
Piezoelectric bimorph - produces a voltage when flexed
Toxic gas:
Carbon monoxide detectors...
http://en.wikipedia.org/wiki/Carbon_monoxide_detector
It is a HUGE field, so you will have to do some web searching. Manufacturers pages are usually good places to find explanatory info.
Temperature:
Thermocouple - makes use of the fact that a junction of 2 different metals produces a voltage difference which varies with temperature.
Thermistor - a resistor whose value changes with temperature. There are 2 types, PTC and NTC, positive / negative temperature coefficient.
Pressure:
Typically you have a silicon membrane with a force sensor (strain gauge) on it. Pressure on one side of the membrane causes it to distort, which causes a change in resistance in the sensor.
Light:
Photodiode - a diode that leaks current according to how much light falls on it.
Light-dependant resistor (LDR) - does what it says!
Radiation:
Ionisation type detectors - basically a gas-filled tube. When a radiation particle strikes a gas atom it creates an ion, or charged atom. An electric field attracts the ion to a plate, where it is detected as a pulse of current.
Scintillation detector - use a crystal that produces a flash of light when struck by a particle. The flas is detected by a light sensor.
Force:
Strain gauge - a thin film of resistive material. Resistance changes when it is flexed.
Force sensing resistor (FSR) - resistance changes when squeezed
Piezoelectric bimorph - produces a voltage when flexed
Toxic gas:
Carbon monoxide detectors...
http://en.wikipedia.org/wiki/Carbon_monoxide_detector
What would be a good intruder alarm system (sans video) VALUE FOR MONEY wise?
i know there are motion detectors, glass break sensors, door/window sensors and video. i know too that there are auto dial systems. heat and carbon monoxide sensors.
but i just want the simple door/window sensors & motion detectors with dial feature thank you!
Answer
the simplest one is the G.E. Simon XT. It is a wireless, self-contained, user-friendly alarm system that dials out and is, in my opinion, the easiest one for a regular person with no alarm technician experience, to program.
the simplest one is the G.E. Simon XT. It is a wireless, self-contained, user-friendly alarm system that dials out and is, in my opinion, the easiest one for a regular person with no alarm technician experience, to program.
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