Pir sensor and 555 timer

[together]

hi guys... i am working on a project which basically contains a PIR sensor. Since PIR sensor detects the motion of human and provide a high pulse for a short time...I try to maintain the high pulse for minimum of 1 minute....

That means ,when a motion is detected by a pir ,the output should be high for the next 1 minute..I try to do it with 555 timer....but i have no circuit......If anyone knows the circuit plz help me.....

 

[DerStrom8]

You'll want a 555 timer in monostable mode (aka "one-shot") that resets automatically after the output goes low (after 1 minute, in your case). I can get the circuit for you, but it'll probably take a little bit. If you're willing to wait a little while, I'll have it for you as soon as I can. If anyone else already has the circuit, please feel free to help out
Der Strom

 

[ericgibbs]

hi guys... i am working on a project which basically contains a PIR sensor. Since PIR sensor detects the motion of human and provide a high pulse for a short time...I try to maintain the high pulse for minimum of 1 minute....

That means ,when a motion is detected by a pir ,the output should be high for the next 1 minute..I try to do it with 555 timer....but i have no circuit......If anyone knows the circuit plz help me.....

hi,
Look at this version.

 

[DerStrom8]

My apologies. I meant that you simply needed a 555 timer in monostable mode. You don't need an "automatic reset" as I said before. There is a simple circuit like this at:

https://www.unitechelectronics.com/NE-555-FIGURE28A.gif

ericgibbs' circuit, of course, is actually designed for a PIR motion detector, so his would probably work better. The circuit at the link above is quite simple, however, and should work just fine. All you need to do is connect the output of the PIR sensor to the "touch plate." To change the length of the "on" time of the output, replace the "100k" resistor with a 50k potentiometer and adjust it until the circuit turns on for 1 minute. Also, depending on the load, you'll probably want to replace the red LED with a transistor, with which you could drive more devices. Hope this helps!
Der Strom

 

[Dragon Tamer]

I thought that the output of a PIR slowly oscilated between high and low outputs in cycles, but it does so in a saw tooth wave form. The output suddenly goes high or low depending on if the output is increasing or decreasing. At least that's what happens with the PIR that I bought from radio crap: https://www.electro-tech-online.com/custompdfs/2010/09/2760033_PM_EN.pdf