here's the scenario I want to be able to turn my pc on and off by waving my hand above the front of it reading into it I need a PIR sensor what do you guys think? am I on the right lines?
Not sure about the technical things, sounds good but you'd have to think were you put your pc other wise you may move your leg or somethin and it'll turn off.
Maybe think about an LDR, and invert the signal? I was thinking about the same thing recently, and that was the best I could come up with... You would need to set limits though... you don't want your PC turning on if you turn off the lights... (running an LED off +5vSB to keep the LDR high?) Just a few thought's I had until I decided on something different... Hope it helps...
Possibly some sort of a laser / sensor setup? Maybe put the sensor at the end of a thin matte black tube so that ambient light wont trip it. And then just wave your hand to break the beam...
How about an ir setup where you have to break the beam? Like what you see at the entrance of some stores. You can have the ir led & ir sensor on the pc, and the reflector can be wherever, just as long as all three are in alignment. eninja: This is just like devenfore's suggestion actually but IR
have a look at the touch-sensitive on-off switch thread. it uses capacitance, so you have to have your hand pretty close to the sensor, but it is a similar effect to what you want to do. http://forums.bit-tech.net/showthread.php?t=100148
I couldn't get a touch switch to work without actually touching it, but the biggest piece of metal i used as a trigger was about 10 x 4 cm and ~1mm thick. IIRC, the datasheet states that going much bigger than this means the touch switches apparently become overly sensitive and can be falsley triggered.
Someone in the project logs did something similar with the cd tray button. I don't remember who it was though.
The problem with an IR LED and detector is that I wont have anywhere to put the IR led, as I want to wave my hand over the top of the pc to turn it on and I can't install an IR led in my uni ceiling and I don't want my pc to turn on when I turn out the lights to go to bed/light gets turned on in the morning I've been reading about PIR sensors however I'll need somehelp coding and building it (only got a B at systems in my GCSE's and that was 2 years ago)
Oh yeah like you said in the op! A PIR would be perfect I somehow drifted off into beams and forgot about the whole proximity thing This might work well: http://www.electronic-circuits-diagrams.com/alarmsimages/alarmsckt19.shtml The green link has a circuit diagram - no need for the relay and the attached vertical 9v supply line, just hook the mobo trigger to the collector of the BC107
hehe I'm not as n00b as I sound I've found another little circuit with some help from another forum that should work and it runs on 5v so should be ok but thanks for the suggestion, that circuit works in roughly the same way as the one I'm planning to use so
EvilNeverDies can be pm the schematic with 5v im interesting too. thnx Cheapskate@ the topic with dvd activate with pir senson but the guy never post the schematic http://forums.bit-tech.net/showthread.php?t=149885&highlight=rambo&page=7
Until a cat or something knocked it off, I had a pot frog on the pond wall, a slightly upmarket version of this. Looks a damn cheap way of getting all the parts.
I have a "Head on a Plate" that has a sensor to make him start talking. Animatronic eyes and mouth.Uses a couple AA batteries. Wave your hand or walk by the head and a tiny pin hole in his forehead senses it and turns on. The head is like this: If you look close you can see the tiny hole . The electronics can't be too expensive as the whole head cost $10. john
