Motion sensor thing

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danielwheeler

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#30299 4-Feb-2009 07:24

ok, you know the lasers that are inside of candy machines that see if the candy was dropped? i wanna make one of those for my hallway so i can know if someone's coming toward my room. Does anyone have a plot to make one. I'm not doing anything illegal, and I'm not a paranoid freak, I just wanna make a fun circuit.

Ps. i do have a basic understanding of electronics (digital and non)

danielwheeler

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#193886 4-Feb-2009 08:25

bumpism

danielwheeler

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#193889 4-Feb-2009 08:38

no one?

chiefie

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#193891 4-Feb-2009 08:52

Why don't you just get one of those door alarm/sensor thing that you often see at the shop door where it make "buzzzz" as someone enter?

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gehenna

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#193896 4-Feb-2009 09:08

Perhaps wait a while to see if anyone answers? It's only just gone 9am so people are still arriving at work and waking up at home, having breakfasts and showers and getting ready for their days. Its highly unlikely you'll get a response if you're bumping this early in the morning.

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#193914 4-Feb-2009 10:10

*hehe* Gehenna, based on the flag of the posts... he's from USA...

<french accent>American!</french accent> *hehe*

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Fossie

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#193924 4-Feb-2009 10:34

What you need is a programmable IC, and an ultra sonic sender and receiver. So than when someone walks infront of the ultra sonics, the time for the sound to return is different and your IC can do whatever you want it to do...send out sound to a speaker etc.

There must be a laser diy kit out there, but I think it would be much harder to make from scratch. iirc they work by the laser connecting with a metal plate and giving it energy(simplified that a lot), and when something gets in the way, the circuit is broken...then the same as before.

or an even simpler circuit would be a laser aligned with an LDR.

danielwheeler

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#194165 5-Feb-2009 07:03

gehenna: Perhaps wait a while to see if anyone answers? It's only just gone 9am so people are still arriving at work and waking up at home, having breakfasts and showers and getting ready for their days. Its highly unlikely you'll get a response if you're bumping this early in the morning.

good point. i tend to forget that this isn't a US site. sorry.

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danielwheeler

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#194166 5-Feb-2009 07:05

Fossie: What you need is a programmable IC, and an ultra sonic sender and receiver. So than when someone walks infront of the ultra sonics, the time for the sound to return is different and your IC can do whatever you want it to do...send out sound to a speaker etc.

There must be a laser diy kit out there, but I think it would be much harder to make from scratch. iirc they work by the laser connecting with a metal plate and giving it energy(simplified that a lot), and when something gets in the way, the circuit is broken...then the same as before.

or an even simpler circuit would be a laser aligned with an LDR.

coolio. i'll totally do the laser LDR thingy. sounds easiest.

stevenz

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#195174 10-Feb-2009 19:45

photo-electric light-beam. Cheap.

Most of the cheaper laser-diodes aren't designed to be used for extended periods (the type used in laserpointers etc), so you'll want to invest in a better quality one or it'll likely go "pop" after a few hours.

Or, get a rug and stick a pressure-plate under it, ultra-easy and doesn't require any IC programming. Plus you won't risk blinding your pet(s) if you happen to have any and were going to mount it low.

I had one years ago which was just an LDR wired pretty much straight into an RS232 port of an Atari 800XL which I could then PEEK to see what the current resistance was and do things accordingly. The end result was that you could use it to trigger a relay to turn the lights on when it got dark outside or something similar. Back then laser-diodes were a bit out of my price range. It was amusing to use it to change the sound pitch relative to light as a sort of poor-mans theramin.

danielwheeler

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#199330 5-Mar-2009 06:40

i didn't think of pressure sensitive, thanks

gomez

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#199882 8-Mar-2009 11:52

Why not just get a PIR and blind the sides of it to narrow the detection field?

All you need then is 12VDC, and something to sound. Should be about total of $20 spent.