I would like to build/design a circuit that utilizes a PIR motion sensor. Premise of the circuit is this...If it detects motion for 5 continous seconds or less...nothing happens. If it detects continous motion for 6-10 seconds it triggers a relay or switch to turn on a light or output device. Thoughts?

 

hi David,
Welcome to AAC.
A standard PIR module and 555 Timer IC, could do the action required.
This type of PIR module can be set for repeat trigger.
What is your level of electronics knowledge.?
E

 

What turns the output off after it triggers?

 

hi David,
Welcome to AAC.
A standard PIR module and 555 Timer IC, could do the action required.
This type of PIR module can be set for repeat trigger.
What is your level of electronics knowledge.?
E

Thanks for replying Eric. My electronics knowledge is limited but I am sure I could follow a schematic or pictorial diagram. Would you know where I might find a schematic of such a circuit or even one that is close? I have played a little with a 555 timer and understand the versatility of this chip and its timing capacity.

 

What turns the output off after it triggers?

What turns the output off after it triggers?

I would probably use a timer circuit (555)

 

hi David,
Welcome to AAC.
A standard PIR module and 555 Timer IC, could do the action required.
This type of PIR module can be set for repeat trigger.
What is your level of electronics knowledge.?
E

Sorry. I missed the attachment you sent the first time. thanks.

 

I would probably use a timer circuit (555)

So how long after it's turned on?
Do you want that turn-off time to be independent of how long the input signal stays high?

 

hi David,
I will check one of PIR modules to confirm the pulse widths when set for Repeat trigger.
The PIR when triggered will set a 7555 monostable with say 5 sec time delay, when that delay expires a second 7555 set for say 10secs will trigger.
If the PIR pulses are still present, due to a continued movement, during the second 7555 period of 10s , the Alarm signal will occur.

What voltages do you have available for the project and what will the alarm device be.??

E

 

So how long after it's turned on?
Do you want that turn-off time to be independent of how long the input signal stays high?

After the output is turned on I would like the adjustability to vary the (on time of the output) to anywhere between 30 seconds and 2 minutes. Does this make sense? Thanks again for all the support. I like this forum.

 

hi David,
I will check one of PIR modules to confirm the pulse widths when set for Repeat trigger.
The PIR when triggered will set a 7555 monostable with say 5 sec time delay, when that delay expires a second 7555 set for say 10secs will trigger.
If the PIR pulses are still present, due to a continued movement, during the second 7555 period of 10s , the Alarm signal will occur.

What voltages do you have available for the project and what will the alarm device be.??

E

12 vdc and I will probably have a siren or horn hooked up. I'm thinking i will probably need either a relay or power transistor to handle current draw on the output side.