Motion Activated Motors

[Noah Abbott]

Hello,

I am fixing a project right now that is a rube goldberg machine, activated by people walking by. What I want is when someone walks by, it sends a signal to some timer, and then runs the motor that lifts balls up for just one second. So I'm looking for two devices, and I just can't find what I'm looking for. This runs at 120V, and doesn't need varying speeds or anything, it just needs to run for 1 second when a person passes by. I assume that'll take a motion sensing device (preferrably somehting small and hidden like a photoelectric switch) and a timer device.

 

[davenn]

. I assume that'll take a motion sensing device (preferrably somehting small and hidden like a photoelectric switch)

there are proper PIR ( Passive InfraRed) detectors for this ... used for intruder alarms

 

[Noah Abbott]

there are proper PIR ( Passive InfraRed) detectors for this ... used for intruder alaems

I suppose I could, but those tend to be large and obvious, not usually hidden, if I'm correct.

 

[Noah Abbott]

Also, do you know a device that would then tell the motor to run for 1 second? I know there are physical timer devices that can, but I have no idea how to search for it. I suppose I could also use a mictrocontroller, but it'd be nice to just have a hardware component.

 

[Noah Abbott]

I suppose I could, but those tend to be large and obvious, not usually hidden, if I'm correct.

Actually a correction on myself, after looking it up I suppose there are some that I could hide under the machine just as well. Is it okay that this is in the front entry way where cold air rages in all the time?

 

[davenn]

I suppose I could, but those tend to be large and obvious, not usually hidden, if I'm correct.

well use some imagination and recase them
.... you are not going to get anything much smaller than the internal cct board that will do the first part of what you require

 

[davenn]

Also, do you know a device that would then tell the motor to run for 1 second? I know there are physical timer devices that can, but I have no idea how to search for it.

a NE 555 timer circuit triggered by the PIR would probably do the trick
others on here may be able to help with that

 

[davenn]

Is it okay that this is in the front entry way where cold air rages in all the time?

probably not a real problem ... they get used for outside home front door light trigger switches all the time
the main trick is ... DONT point them where the sun will shine on them ... or some other heat source .... heaters etc

 

[Bluejets]

Most of the home detectors have "zones" that radiate down and sideways. Result being they detect movement mostly by movement across the zones rather than straight in. They usually have a switch wire out at the voltage of the supply so this could start your timing via a relay or similar. Problem may be that even set on "test" they give a switch output for maybe 5 to 10 seconds. Arduino etc. units may suit better.

 

[KTW]

Some pir's have adjustable timers built in.

 

[Bluejets]

The op wants it to operate for 1 second. Those domestic pir's are difficult to set exact times in minutes let alone seconds. As I pointed out, even on "test" the trip time would be too long. Hence reference to the Arduino unit.

 

[KTW]

I guess I read 1 second but for some reason I thought it was 1 minute.
Carry on.