I am helping a local church setup an AV system. The plan was to simply use the 12v trigger to control the screen making operation as simple as possible. The only problem being that the projector does not have a 12v trigger output. First off, I thought this was a standard and common feature and I was surprised to find that it was not included. Second, what would you suggest as a workaround? The only wire run between the screen and projector is a 2 conductor 20awg.

Look up the Niles FG00242, a Voltage-Triggered AC Power Strip. This is also sold under its old number, the AC-3. I've seen this on amazon. This should do it for you. There might be similar products out there, but I'm not aware of them.

This thing senses how much current is drawn by one outlet, and when enough is sensed, it turns on another outlet. Plug a 12 volt wall wart into that switched outlet and you'll have a nice trigger voltage for your 20 gauge wire pair.

This thing doesn't work when it's being used with a product that doesn't use enough current for the sensing device to reliably be triggered on.

There are many outlet current controlled strips on amazon now. Starting at only $12.66
The only problem is most are 6-10 outlet in size and kind of large to hide or manage.

[Link: amazon.com]

In the past I've used the Niles CS12V when this happens, which is also a current sensing 12V switch setup. It's a solid piece that just works and installs easy, which would be my recommendation.

Ernie is recommending a model that's been discontinued for some time now. The CS12V is the replacement. The CS12V will serve your purpose perfectly.

Niles LS-1. Discoed, but available on eBay. If projector has a light that comes on besides the obvious. It can sense this. Elan also made one that had filters I believe and could sense color change. Sound as if the current sense recommended might be best option.

Thanks for the recommendations. I’ll check those out. I have been out of the installation game for several years now but we always used to use 12v triggers for simple commercial setups. Even the screen did not have 12v trigger capability. I had to order a separate module. It was my own fault for just assuming that the projector had a trigger output. Is this a feature that is disappearing?

Depends on the brand.

What equipment are you using? Can you use a remote-controlled outlet, like the ones for power tools and dust collectors? Not an elegant solution, but they work. I bought one for less than $20, a few weeks ago.

If you can't supply power from a common location, this would be an easy solution-

[Link: homedepot.com]

I love those things. I've got a few that I use in my place. They used to only be available around Christmas, presumably for turning lights on and off in places where there usually aren't any lights -- outdoors along the eaves, for instance.

One thing, though -- those will still take some doing. You can't just plug the screen into the switch. Screens require a constant hot to power the screen when it's going down and when it's going up, with the trigger being on to lower the screen and off to raise it. With one of these you'll still have to get a 12 volt or similar supply to present the actual trigger voltage.

Any chance the projector has a USB port that switches 5v on/off?  If so, you can put together an inexpensive relay to control the screen.

I think I posted some time back about using the USB on a TV to control contact closure for an art lift.

Depends on too many factors. I always check when specifying whether a trigger is present, and how the user wishes to have the screen controlled.

I once got stung by a client's projector when I estimated installation based on using the Marantz projector's trigger output. That 12 volt trigger only put out about 25 mA and I couldn't find appropriate equipment that needed 25 mA or less to trigger.

So, you're saying that you ordered a 12V trigger module and it now has this feature?

I installed a screen from SnapAV and it has IR and 12V trigger- what screen are you using- many house of worship installations use Bretford.

If you now have 12V trigger ability for the screen and that 20-2 wire is available from the projector, can I assume the trigger module needs 12VDC to drop the screen and 0V to raise it? If so, you can use the remote switch in the link I posted and use an adapter to make one outlet power two devices, so you can connect a 12VDC wall wart and a Bosch-style relay. YOu should be able to buy one from any car audio/security shop, auto parts store, Parts Express, etc- they're cheap and a security camera wall wart is good enough.

Maybe they expected people to buy an accessory from them, or build something that uses a FET as the switch.

There are two pretty important reasons why I only suggested a totally self-contained solution to this problem: They are UL approved. You don't have to take on a design and construction project, even though this is a very simple item.

As soon as you start to wire up 120 volts, you're selling your customers items that are not backed by UL as to safety. This makes you liable for any subsequent electrical shock or fire.

[This sentence replaces the two paragraphs that would describe the multiple steps needed to invent, purchase parts for, and assemble such a device.]

And all that doesn't mean it will be UL approved. And, at least in Los Angeles County, all devices connecting to 120 volts must be UL approved to be legally sold.


Marantz didn't have such a device. this was a dozen years ago and I never checked RDL, but it's the kind of thing they'd have. In fact, they have the ST-LCR1H at $106.00. And the specs don't list the required trigger input current!