Dropping voltage to Ocelot

[hgupta1]

I would like to connect an Audio detection module from Xantech to my Secu-16 to detect when my record player is on.

I am using this Xantech module to detect audio along with their CBCSM1 block that outputs 12V when it detects audio. 

Apparently this is too much voltage for the Secu16. What's the best way to drop this down to a useful voltage that the Ocelot/Secu16 can accept? Perhaps a relay or a resistor?  I'm clearly not that good with circuitry.
 
I think Secu16 input is limited to less than 5 volts or is expecting a dry contact closure.

 

[BraveSirRobbin]

There are many ways to do this.  One way would be using the analog reading of the SECU16 and setting up an "on" "off" threshold based in the 0-5 volt expected input.  Directions on how to do this is HERE under "Setting Threshold Value".
 
You need to ratio down the 12 volt signal into something within the Ocelot's range.  You do this using divider resistors.  One suggested method is shown in the attached pic.  This will only use three milliamps draw from the Xantech unit and dissipate minimal power so you can use 1/8 Watt resistors.
 

 
This will yield a value slightly over three volts, so you can set up a threshold value of say 2.5 volts in the Ocelot to register an 'on' and 'off' signal.
 
You could also use a 2.2K  in place of the 2.7K and get a value of 3.75 volts to the SECU16.
 
The other way is to use a  resistor  relay with a 12 volt DC coil; then have the contacts connected to the SECU16 input and set that up as a 'supervised' input
 
The problem with this method is I don't know the current drive capability of the Xantech unit (as most coils are low resistance around 100 ohms or so) and may require as much as an 1/8 amp draw from it.
 
An Elk-912 or Elk-924 relay will work well in this scenario and draw minimal current from the Xantech unit.

 

[Desert_AIP]

You could also do it with a 12VDC relay and connect the dry contacts to the SECU input.

ETA: I missed that part in BraveSirRobbin's post.

 

[BraveSirRobbin]

You could also do it with a 12VDC relay and connect the dry contacts to the SECU input.

Last two paragraphs of my post had the wrong wording.  Thanks for the catch.
 
I should have said 'relay' instead of 'resistor'.
 
I fixed the posting.

 

[Desert_AIP]

An ELK-912 draws 30 mA.

 

[BraveSirRobbin]

An ELK-912 draws 30 mA.

Yes, good point and this should work well.  The other thing I noticed (and forgot about) is their 'sensitive' relay draws even less (1.2 milliamps).
 
http://www.elkproducts.com/product-catalog/elk-924-sensitive-relay
 
I'm getting old I guess...
 
I edited my original posting to include these corrections!

 

[hgupta1]

Wow!  Thank you guys so much!  I always forget how awesome this forum is!  
 
Is there a best way out of the great options that y'all have given me?  I like the idea of resistors because I think there that it might be more responsive.  I was using an x10  powerflash previously, but it was so slow that that I would miss the beginning couple of notes of each record.
 
By the way, it is a shame that xantech is discontinuing this audio detection module.  It was the only thing I could find that could detect the low currents used by the record player.   And there is still nothing better than just putting the needle on the record and walking away with the ocelot setting the sound system to the right input.  

 

[hgupta1]

I need to brush up on my electronics too!  Resistors make sense in my mind, but relays are still magical devices for me.

 

[Desert_AIP]

If you want to go the electronics route you could also use something like an opto coupler or schmitt trigger IC which will provide sensitivity, low power consumption, no mechanical device to fail and isolate the input from the trigger signal.
 
The 12VDC relay is probably the easiest to implement.
The others may be more sensitive and react more quickly.