# FS-2 Flicker Circuit Trigger Question



## MBrennan (Sep 22, 2008)

Greetings all,

I'm trying to figure out a way to trigger a flicker circuit that uses a FS-2 fluorescent light starter, and have it stay on for a short period of time (a few seconds).

I tried using a motion sensor (made for use with fluorescent fixtures). The problem is, the flickering of the circuit causes the sensor to stay "on" all the time. It must have something to do with re-setting the internal timer every time the starter goes "off."

It may be time to learn more about the picaxe controller or something similar.

Anybody have any suggestions?


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## corey872 (Jan 10, 2010)

How do you have the sensor / starter circuit wired up now? I wouldn't think anything going on with the starter should re-set power to the sensor. Might just need to be wired differently or use a relay between the sensor and starter.


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## Otaku (Dec 3, 2004)

corey872 said:


> Might just need to be wired differently or use a relay between the sensor and starter.


That's what I'm thinking. If the starter is sending any spikes back up the line to the sensor, isolating it with a relay should solve the issue.


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## MBrennan (Sep 22, 2008)

The effect I'm after is this:

I have a mirror with a back lit image inside and lights on the outside (ala peppers ghost). I used the "lightning power outage" idea to get the lights to flicker in opposition when triggered. The only difference is that I used the starter to get the flicker. 

It's actually two circuits. The first is just line input, through a photocell outlet, to the outside lights. The second is the motion sensor, to the starter (in series) to the interior lights (and the nightlight to trigger the photocell). All inside a lightproof box.

The problem is, the motion sensor, once triggered, never resets to "off" and the lights keep flickering.

I thought about using a relay to separate the motion sensor from the starter. I understand the theory , but don't have any experience actually wiring it. I don't even know where to get the relay. It would need to be a 110 to 110 relay.

Am I going to right direction?


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## MBrennan (Sep 22, 2008)

Also, I think the resetting has more to do with the starter opening the circuit and starting the motion detector clock over, like turning off the power to it, rather than sending any kind of spike up the line.

No expert on the subject though.


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## corey872 (Jan 10, 2010)

I think the problem is definitely the motion sensor / starter in series.

Still a bit confused about the overall effect. I get the flickering / alternating effect. As I understand it, you want a normally front lit mirror most of the time, then when someone walks by and triggers the motion sensor, the front lights drop and the rear lights kick in - in an alternating/flickering fashion - then as they clear the motion sensor, the lights return to a normal front lit mirror? Are you using the photocell as a 'reverse trigger' to shut the front light off when the rear lights are active?

Based on that, it seems like you'd run power straight (always on) to the motion sensor. Then run the rear light from the output side of the motion sensor. The sensor and light wouldn't be in series, it would be more of a parallel connection.


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## ouizul1 (May 22, 2010)

MBrennan said:


> I don't even know where to get the relay. It would need to be a 110 to 110 relay.


Radio Shack carries DPDT (two sets of on and off contacts) 110 Vac relays for $8-10. You can get them cheaper online, but then you also have to pay shipping.


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## MBrennan (Sep 22, 2008)

corey872 said:


> I think the problem is definitely the motion sensor / starter in series.
> 
> Still a bit confused about the overall effect. I get the flickering / alternating effect. As I understand it, you want a normally front lit mirror most of the time, then when someone walks by and triggers the motion sensor, the front lights drop and the rear lights kick in - in an alternating/flickering fashion - then as they clear the motion sensor, the lights return to a normal front lit mirror? Are you using the photocell as a 'reverse trigger' to shut the front light off when the rear lights are active?
> 
> Based on that, it seems like you'd run power straight (always on) to the motion sensor. Then run the rear light from the output side of the motion sensor. The sensor and light wouldn't be in series, it would be more of a parallel connection.


You are exactly correct. The motion detector/starter/back light circuit is in parallel with the photocell/front light circuit. And both are wired "hot." Only when the motion detector/starter/back light triggers does the photocell "reverse trigger" the front lights.

Also, thanks for the Radio Shack info. I'll check into that. Seems like that may solve the problem.


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## MBrennan (Sep 22, 2008)

Update (of sorts);

The effect I'm after works, but I still can't get it to turn off/reset.

I wired a relay to the motion sensor. Now the motion sensor only triggers the relay, which then makes the starter circuit do it's thing. But for some reason, the motion sensor (and relay) still never turns back off.

The LED indicator on the motion sensor goes off, and if you move in front of it again, the LED comes back on, but there is always power going to the relay coil (I can see if the contacts move or not).

Only when you turn the motion sensor selector to OFF, does the power to the relay coil quit, and the contacts "open".

The only thing I can figure, is that there is always some voltage running through the motion detector and to the relay coil. I haven't measured it yet because I heat shrunk everything up.


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## corey872 (Jan 10, 2010)

I can think of a couple of scenarios:

Is this motion sensor originally designed to run lights? If so, perhaps there is just not enough current running on the output (with only the relay) to properly trigger the 'off' circuit.

It could also be possible the motion sensor is just bad. Does it trigger with a 'click' ? If so it's probably triggering with a relay which should be pretty robust. If there is no click, then it might be a mosfet/transistor set-up which are more prone to damage and little things like being able to turn on, but not off.

If it were me, I'd probably try to return it to it's original triggering by removing the 'circuit' and just wiring up a light bulb. See if the bulb triggers normally.

Also, if you have a relay, you could just use a double throw relay and wire the front lights up to the normally closed side, backlight to the normally open side. Then you can eliminate the whole photocell / light / box arrangement. The relay would automatically switch between the two lights


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## MBrennan (Sep 22, 2008)

Thanks for your suggestions, it's greatly appreciated.

I'm going to test the motion sensor tomorrow to see if it's bad. The detector is designed for lights, both fluorescent and incandescent. And I can't hear it click when it activates. Also gonna dig around and see if I've got another one.

I may end up doing just as you said and use the relay to switch between the two. However; I like the effect of having the lights flicker in opposition to each other, rather than just having the front lights go off and the back lights flicker.

More to follow:


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