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Registered Member #617
Joined: Fri Mar 30 2007, 07:29PM
Location: Buffalo NY
Posts: 49
I am working on a project which involves passing a an object about the size of a soccer ball through a 36" hoop. I considered using a diode or laser and a photoresistor to detect movement but the balls motion is only detected when it passes through the hoops center. So my question is does anyone know of a better way to detect motion? One day I would also like to be able to detect the velocity of the object passing through the hoop but thats not a project for today. I need to build six of these devices so I would appreciate inexpensive ideas but all are welcome. thank you.
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
How about a pyroelectric sensor as used in most other motion detectors?
In England, it's usually much cheaper to buy a retail unit, and take the guts out, rather than buy parts/sub-assemblies individually.
I see there's a DIY pyroelectric motion detector here, and you will doubtless find more if you look:
Pyroelectric Infrared Motion Detector, PSoC Style
Ultrasonic transducer pairs for Doppler motion detector burglar alarms are also available at bargain-basement prices, (because they are no longer in fashion,) but a lot more tricky to set up than disemboweling a cheap PIR unit which already comes with a Fresnel lens.
Registered Member #74
Joined: Thu Feb 09 2006, 09:17AM
Location: Nottingham UK
Posts: 99
Ultrasonic transducer pairs for Doppler motion detector burglar alarms are also available at bargain-basement prices, (because they are no longer in fashion,) but a lot more tricky to set up than disemboweling a cheap PIR unit which already comes with a Fresnel lens.
But much easier to get good velocity information from. If you can get an old ultrasonic Alarm board or hack up a reversing parking aid, you can get a proximity output. The Rate of change of this output gives you velocity.
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Question about Motion Detectors
