Output driving a strobe not working

[lugnut]

I have an ATW Doberman siren/strobe, but I'm only using the strobe. I've hooked Output 16 to it, and wrote a rule to turn on output 16 for 4 seconds every 15 seconds. The strobe doesn't light.

With the strobe disconnected, and a multimeter hooked to the output16 wires, it reads the 12VDC for 4 seconds every 15 seconds, as expected.

With the strobe connected to a separate 12VDC power supply, it flashes fine.

Do the ELK outputs not like flashers and I have to go through a relay (w/ output 16 as the trigger) and a separate power supply?

Any other things to try?

 

[mimitche]

Try it on output 3; That's the only one a strobe would work on for me. I can't remember the specifics but it was something about the power draw of a strobe.

 

[lugnut]

Try it on output 3; That's the only one a strobe would work on for me. I can't remember the specifics but it was something about the power draw of a strobe.

Thanks. Unfortunately my output-3 and the relay is already in use.

I did a search on "strobe" but didn't find any discussions on perculariaties with strobes and why output-3 is special.
Anyone else remember?

 

[lugnut]

The output is probably current limited???

That might be it. I just looked up the current rating of the outputs and it is only 50mA. For some reason I was thinking they were 200mA.

The strobe draws 90mA according to the specs, so it would have been over-drawing. Good thing there are thermistors in the outputs. So I guess I'll have to use output 16 to switch a relay that powers the strobe from Vaux or an external power supply That sound right?

 

[BraveSirRobbin]

Are you sure the strobe is only drawing 90 milliamps? That seems to be a small current amount for a strobe.

 

[Photon]

I plan to power the strobes either directly from the Elk's battery using a fused circuit or from a separate power supply. I'll save the PTC-protected outputs for more important gadgets.

 

[Spanky]

The J16 outputs which include Output 16 are current limited to around 50milliamps through a resistor to keep installers from connecting large current devices and blowing out the output transistors.

You will have to interface a 12 Volt relay like the ELK 912 relay or use the M1RB relay module. A power transistor or power FET could also be interfaced if you are into breadboarding.

 

[lugnut]

Are you sure the strobe is only drawing 90 milliamps? That seems to be a small current amount for a strobe.

Your question got me wondering. I took the unit apart and tested/measured some more. I hooked the strobe directly to a stand-alone variable power supply. The strobe is based on 4 white LEDs, so 90mA would not be out of the question. However, it actually draws about 150 mA at 12VDC in steady state (as opposed to the 90mA claimed on the package), and worse yet, after the strobe is running for about 3-4 minutes, the LEDs overheat and shut down.

There is either a manufacturing defect, or it's just a disfunctional design that overdrives the LEDs. Either way, there's just no excuse in a device with so few parts.

I think I will steer clear of ATW's products in the future.

Now to try and find a replacement strobe that can run indefinitely and is relatively low current, since it's possible the strobe may be going off for hours before anyone comes home and sees it, to deactivate it. Super high brightness is not a requirement, since I'll be using it as an indicator viewed from no more than 25 feet away, not a light source. But it does need to be visible in sunlight so flashing would be preferred. Any recommendations?

 

[BraveSirRobbin]

Hmmm, even the Elk Strobes state that they are not designed for "continuous duty applications", so you may have some trouble with the "indefinite" spec.

 

[lugnut]

Hmmm, even the Elk Strobes state that they are not designed for "continuous duty applications", so you may have some trouble with the "indefinite" spec.

Yeah I saw that while searching. "Not designed for continuous duty applications" is kinda ambiguous and unhelpful. Is it a few minutes? a few hours? what?

I wonder what it means exactly, and why the limitation can't be overcome? There are LED flashlights that run indefinitely (til the battery dies, but several hours), and LED replacements for 50W 12V MR16 halogens that run continuous and have comparable lumens. What is the distinction? Anyone?

 

[rfdesq]

What are you trying to do with the strobe?

 

[BraveSirRobbin]

I don't think it's so much the LED's they are worried about with "continuous duty" but rather the voltage triggering circuit itself (FYI, may be wrong on this assumption...)

 

[WayneW]

All Electronics has a few Xenon strobe models. They draw 120mA to 150 mA and don't say anything about long-term use.
http://www.allelectronics.com/cgi-bin/item...BLUE_LENS_.html
just search for "strobe" and you will see their other models/colors.

 

[BraveSirRobbin]

All Electronics has a few Xenon strobe models. They draw 120mA to 150 mA and don't say anything about long-term use.
http://www.allelectronics.com/cgi-bin/item...BLUE_LENS_.html
just search for "strobe" and you will see their other models/colors.

I purchased the white strobe years ago. It only goes off on an alarm, so I don't have a lot of run time on it. It does produce a nice, bright flash.

 

[123]

This is waaaay too simple to be failing ...

The circuit is composed of the following items connected in series:
12VDC voltage source (battery)
Output 16 acting as a switch
Strobe Light

Close Output 16 and the strobe should activate. If it does not, then either the circuit is not as described, the strobe's polarity is reversed, the battery is wonky, there's a faulty wire, or all of the above.