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want to make a 12 volt system that operates on a PIR

ianb

Sep 23, 2013
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I want to make a 12 volt system that operates on a PIR.
I would like the PIR to stay on for say 2 minutes and then shut down and reset regardless of motion still detected.
I am a real novice , so if you could speak slowly it would be a big help
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
25,510
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25,510
Let's get those specs a little clearer.

You want a PIR detector, when triggered, to power some 12V system. Presumably the PIR is to receive power from the same 12V source.

What is this load? DO you know how many amps it draws? Or its power in Watts?

OK, so when the device is powered up the PIR detector is active. When movement is detected (and the PIR triggers) you want the load to be switched on for 2 minutes. At the end of this 2 minutes, the load is turned off. The PIR will no longer be active and movement will not trigger it again -- unless, presumably, power is removed and reapplied.
 

ianb

Sep 23, 2013
4
Joined
Sep 23, 2013
Messages
4
PIR reply

Let's get those specs a little clearer.

You want a PIR detector, when triggered, to power some 12V system. Presumably the PIR is to receive power from the same 12V source.

What is this load? DO you know how many amps it draws? Or its power in Watts?

OK, so when the device is powered up the PIR detector is active. When movement is detected (and the PIR triggers) you want the load to be switched on for 2 minutes. At the end of this 2 minutes, the load is turned off. The PIR will no longer be active and movement will not trigger it again -- unless, presumably, power is removed and reapplied.

What I want is the PIR to feed a small 12 volt gate valve for a sanitary system to allow water through foe say 2 minute and then close down even after there is still movement in front of the PIR.
There would then be a sleep period of say 3 minutes and then the PIR would become active again.
The valve is 250 mA 4.8 watt
Thanks for replying
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
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25,510
A 555 is probably only an outside option because the time delays are getting quite long. Also, the 555 is re-triggerable and the delay between triggering would probably have to be done with another 555.

A microcontroller could eat this up and spit it out, but it does require you have enough knowledge to program it and whatever is required to burn the code to it.

The microcontroller also gives you more flexibility, say to flush once per day regardless of use, etc. It also uses less parts overall.

Do you have any programming experience?
 

ianb

Sep 23, 2013
4
Joined
Sep 23, 2013
Messages
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A 555 is probably only an outside option because the time delays are getting quite long. Also, the 555 is re-triggerable and the delay between triggering would probably have to be done with another 555.

A microcontroller could eat this up and spit it out, but it does require you have enough knowledge to program it and whatever is required to burn the code to it.

The microcontroller also gives you more flexibility, say to flush once per day regardless of use, etc. It also uses less parts overall.

Do you have any programming experience?

No I don't. I am a builder and don't have much experience with electronics. I have now decided to get round the problem from a different direction . I would like to thank you for your help it has allowed me to move on. I may get in touch again to check my wiring on the finished article
 
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