# EFX-TEK PIR and a Nerve Center?



## Death Wraith (Mar 23, 2006)

I need to connect the EFX-TEK PIR to my Nerve Center. On the PIR the connections are: -,+,OUT. On the Nerve Center they are: GND,12V,IN. Before I plug anything in and blow something am I OK to hook directly across? Or might I have to switch a couple wires?

Thanks In Advance!

DW


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## JeffHaas (Sep 7, 2010)

One thing...the Parallax PIR needs only 5 volts, your Nerve Center apparently puts out 12 volts. Someone here will have to tell you how to deal with that, right now it's late and I don't quite remember. 

Otherwise...

GND connects to -
12V connects to + (with some other stuff in the circuit to cut the voltage down)
OUT connects to IN (this is the "signal" line from the PIR)


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## lostskeleton (Aug 30, 2011)

You would need a voltage regulator and possibly a level converter IC.

Here is a link to a voltage regulator that would work going from 12V to 5V

http://search.digikey.com/us/en/products/KA7805ETU/KA7805ETU-ND/965381

If you look at the datasheet you will need a few capacitors too.

I don't know if the Nerve Center will count 5V as a triggered event.
I looked through the manual for the nerve center but it isn't clear.

If it has to be 12V then you will need a level converter IC as well to go from 5V to 12V.

Here is a link to that part:
http://search.digikey.com/us/en/products/CD4050BE/296-2056-5-ND/67303

This might not make sense at all if you are not horribly familiar with electronics...but I know not everyone is.

A much simpler way to make this work if the regular electronics route doesn't work is to get a 5V power supply and connect it to the PID and then run the output of the PID to a relay that will switch on/off the 12V from the nerve center.. a more simple solution.

Let me know if that helps or if you have questions


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## scream1973 (Dec 23, 2007)

I am looking to do the exact same thing.. I have a hand trigger right now that i want to convert to the PIR circuit.. and obviously before monday so i can't order anything..


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## scream1973 (Dec 23, 2007)

Relooking at the nerve centre manual it looks like you could potentially just need the regulator..

!2V supply from the Nerve Center to Pin 1 of the Regulator Pin 3 to the + on the PIR , PIN 2 goes to the - on both the PIR and the Nerve Center and the Out Connects to IN. I am gonna try to mock this up and verfy tonite


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## scream1973 (Dec 23, 2007)

Ok just rough wired this up and we have lift off..
Changed the Trigger on the Nerve Centre to NC..

Put a small board together .. 7805 Voltage regulator Pin 1 in from the 12V on the Nerve Centre 
Pin 2 Connects to the GND on Nerve Centre and the - on the PIR sensor
Pin 3 connects to the + on the PIR
And then the Out on the PIR goes to IN on the nerve centre.. Powered it up and it went nuts for like 60-90 seconds then it appears to be completely functional as i would want it to be..

Have to rig up some longer wire harnesses and make better solder joints..


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## sluggo (Jun 16, 2010)

The manual for the motion sensor does say:



> The PIR Sensor requires a warm-up time in order to function properly. This is due to the settling time involved in "learning" its environment. This could be up to 40 seconds. During this time, the LEDs under the lens will be on and there should be as little motion as possible in the sensors field of view.


I always add a 60 second delay at the beginning of any program I write that makes use of one of these so that it is not false-triggering.

Also, should it be necessary to go the relay route for converting the 5V signal back to 12V as described in a previous post, I would recommend an optoisolator rather than a relay. They are solid-state, so there are no moving parts to wear out or make noise. They also require less current to trigger. The PIR may not be able to source enough power to activate the coil of a relay, but in an optoisolator, all it is doing is turning on an LED.


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## scream1973 (Dec 23, 2007)

The nerve center doesn't require a voltage signal to trigger.. It just has a voltage supply for triggers that require voltage.. 

Ie you can use a hand trigger / pressure mat just hooked to GND and OUT


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