How do I integrate a 12v trigger?

[ScottAvery]

I have a device that can only be controlled by 12v trigger - it slides a lens in and out of place for a projector.  Binary position, one position when no signal, other side when receiving a constant 12v signal.  Dunno what amperage, but it works with the signal sent from my projector.  I want an external control other than the projector and I don't seem to have a device with a controllable output.  My thought was I/O Linc to interrupt a constant 12v signal, or an on/off module with a 12v wallwart plugged into it.

Anyone have a recommendation, or a better way?

 

Thanks!

[PhanTomiZ]

1 hour ago, ScottAvery said:

I have a device that can only be controlled by 12v trigger - it slides a lens in and out of place for a projector.  Binary position, one position when no signal, other side when receiving a constant 12v signal.  Dunno what amperage, but it works with the signal sent from my projector.  I want an external control other than the projector and I don't seem to have a device with a controllable output.  My thought was I/O Linc to interrupt a constant 12v signal, or an on/off module with a 12v wallwart plugged into it.

Anyone have a recommendation, or a better way?

 

Thanks!

Hi,

Quickly, I can think of two ways.  

1.  X10 Addressable 12 VDC wall wort.  I use one of these to light up a decorative 3 VDC picture frame.  Use a simple voltage divider cct. to get it down to operating voltage.  These work relatively well.  I had these from an old X10 camera system that I sold.  Should be able to pick them up cheap.

http://kbase.x10.com/wiki/XM14A

https://www.ebay.com/p/X10-Remote-Controlled-Power-Supply-Model-XM13A/704606892

2.  Instead of using the I/0 Linc, use an On/Off Module and your 12 VDC wall wort. I like to keep backup devices in which I use most often.  On/Off modules can easily be used for more applications than spare I/O Lincs.  They may also be cheaper too.  Instead of using an I/O Linc for my water shut off system, I use On/Off Modules and 120VAC valves.  Again, On/Off modules are almost always my goto devices...

PhanTomiZ

[paulbates]

The other advantage of @PhanTomiZ's second option is that you won't be using power 100% of the time for the step down transformer. Probably not a ton of power, but a tad greener. 

Another way to implement his option 2, instead of the on/off module and having things laying around plugged into each, you could replace a receptacle with an on/off outletlinc and plug the transformer into the wall. It doesn't have the flexibility he mentioned but it might make it a cleaner install.

Paul

[apostolakisl]

It is hard to beat the second option you mention (the on/off module with a wall wart).  On/off modules are dual band, can be purchased on sale for $25/ea (2 for 1 sales are common).  You probably have a spare 12v wall wart sitting around and if not, they are cheap.  This would be reliable and extremely easy to implement.  

[ScottAvery]

Thanks all, I do have both an I/O linc and on/off module on the shelf I can use without further expense, but I would need to find an appropriate 12v transformer.  I have lots of 5v transformers laying about but I don't think I will find a 12v with so little output: 100mA is my understanding.  And I will have to cut the cable to use it unless I find some sort of adapter...

 

Not an electrician:  Can I use a higher rated device and the trigger will only pull what it needs or would a higher amp transformer burn it out?

[mwester]

Voltage is analogous to water pressure, while current is analogous to water flow.

So just like your sprinkler requires the water pressure to be in a certain range, your electrical device requires voltage to be in a certain range.  And with the right water pressure, your sprinkler is only going to sprinkle a certain number of gallons/hour (flow), regardless of how much flow your water main (or well pump) might actually be able to deliver.  The same is true of your device: when fed with electrons at the right voltage, it will only consume a flow of current (100mA in your case), regardless of how much current your transformer/wall-wart is capable of delivering.

Or, short answer: you can use a transformer/wall-wart with a higher current rating with no problems at all.

[ScottAvery]

21 minutes ago, mwester said:

Voltage is analogous to water pressure, while current is analogous to water flow.

So just like your sprinkler requires the water pressure to be in a certain range, your electrical device requires voltage to be in a certain range.  And with the right water pressure, your sprinkler is only going to sprinkle a certain number of gallons/hour (flow), regardless of how much flow your water main (or well pump) might actually be able to deliver.  The same is true of your device: when fed with electrons at the right voltage, it will only consume a flow of current (100mA in your case), regardless of how much current your transformer/wall-wart is capable of delivering. 

Or, short answer: you can use a transformer/wall-wart with a higher current rating with no problems at all. 

Thank you for the detailed explanation.  That was my expectation but I wanted someone to confirm before I risked damage to the device.

I did see a cheap USB 5v to 12v step up transformer that could work if I don't find a 12v adapter.

[ScottAvery]

To close it out, I looked at lots of options and individual parts, but did find a wallwart that came with a prefit attachment to connect to bare wire and I bought a trigger cable with pre-tinned bare cable ends.  Both came in packages of two, so I have two triggers for $20.  I could have bought individual parts, or stripped and connected wires, for less, but thought this was a small price to pay to be sure that it would be a solid connection and not a fire hazard.  Paired an on/off module with a remotelinc single scene switch:  worked the first time, and every time.