Timer Question

[paulrevelcet]

Hello all,first I would like to show you something I have been working on,I just threw up a few pics, when I get more time I will add more detail. pics<p>Now on to my question, I need a timer that is adjustable from 5 sec. to say 30 sec. that is activated by the mains voltage and switches the mains voltage, I need it to come on when I turn on a light but I need it to be a one shot, i.e. triggering once only when the lights are turned on, I am a little nervous when working with the mains, that why I thought I would see if I could get some help with where to start. Thanks everyone.

[jwax]

Not sure if I understand what you're looking for. Do you want a 5-30 sec delay of a relay (switches the mains) after a lamp is turned on, or do you want the lamp to turn on after a 5-30 sec delay?
And by "one-shot" do you mean the switched relay circuit resets itself once the lamp is off?

[dacflyer]

your web page link seems to be a dead link... check it out......

[erkanyigiter]

i don't know the optimum solution, but you can achieve it using a microcontroller if you have a little experience with it. connect the output of light sensing circuit to the microcontroller and track that pin. when the output is active, start the timer and at the end of the time, switch the main voltage.
also maybe you can use resistor-capacitor timing circuit. i have seen it a few year ago so i don't remember the circuit exactly. i think you can find it by searching.
-Erkan

[paulrevelcet]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr> your web page link seems to be a dead link... check it out.. <hr></blockquote> works fine, not sure what browser you are using, I use explorer and firefox.<p>I should have been more detailed, I have a cheep 39 dollar smoke machine that works better that my 200 dollar smoke maching, but the way it works is very simple, you push a momentary push button switch in and it makes fog, I will be using this in a Halloween display, the display is switched on with a light switch, which turns on all the motors and lights, I would like my fog machine to come on with all the other things but only stay on for 5 to 30 seconds(not sure how much fog I will need) and then go off until the lights are switched off and then back on again which would start the fog machine again, everything is mains voltage including the fog machine, all the momentary push button does on the fog machine is complete the 110 circuit, so maybe what I need is a timed shutoff and just take the momentary button out and hook the fogger up to the timed shutoff, that way when the main light switch is flipped, it will make fog for the predetermined time then shut off? what is the easiest way to do this? Thank you.

[zotdoc]

Hats off for good pics of a really cool project!

[Engineer1138]

paul, it seems that a time delay relay would work. They typically run off AC and after triggering, keep contacts open/closed for whatever the delay is.<p>I have one that is adjustable up to I *think* 30 seconds with a top-mounted knob. and it's fractional-horsepower rated, so I'm sure it's heavy duty enough <p>It's one of the many parts in my basement that I don't predict ever having a use for, so it's yours for the price of shipping (say $5?) if you want it. It's about 1.25" square base and about 3" tall, I guess it's about 10 years old, but never used. If you are interested I'll go look for it and give you more detailed specs.<p>If you prefer a brand-new one, DigiKey used to carry a number of them in their "Industrial" section.

[paulrevelcet]

Engineer1138 thats a very generous offer, but I think I would rather come up with a solution where I can easily replace it if it were to break, plus I need about 4 of these, I have looked at the time delay relays but at 70 dollars a pop that is just to high, what I play to do is use a triac and a 555 timer hooked up as a one shot to turn on my fogger, I will use a 9 volt wall wart patched into my light circuit, when the light comes on the 555 will power up and provide me with my delay, at least that is the theory any way and for only about 6 dollars a shot its worth a try, but if this wont work then please tell me how it will, again thanks for your offer and your help.

[Engineer1138]

If I understand correctly it should work fine: 555 in "suicide mode" shuts itself off when time runs out by breaking the current flow through the triac?

[Edd]

WHATEVER? that thing dresses up as....seems like it should be an owl or a giant Furby.<p>In order to have a schematic reference, refer to #1 URL and see if that doesn’t fulfill your needs with just a smidge more increase of R or C elements in the time constants to attain your full 30 sec +. Timing. And if you are squeamish about the AC power situation see the 2nd URL for the incorporation of an optical isolator/Triac into the scheme, in lieu of the mechanical relay, unless you happen to have an abundance of them…or even better yet, a solid state relay, if any of them are at hand.<p>http://www.aaroncake.net/circuits/relaytim.htm
Time Delay Relay Ckt
http://www.eetasia.com/ARTICLES/2001JUN ... AMD_AN.PDF
TECCORs Triac/SCR Interface Circuits<p>Aside…. Paul….I ran across a misplaced floppy with a post reply on your Seeburger amp “Juke Box” and placed it on the tail of the thread.<p>Dacflyer de Jetflyer…that imaging acted a bit squirrelly on my viewer also, showing up as being compressed into 2 inches at the at the screen top…..tapping the maximize gave a full normal image….I think that an errant space got inserted in the HTML coding format. <p>73's de Edd
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<p>[ October 27, 2004: Message edited by: Edd Whatley ]</p>

[paulrevelcet]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>WHATEVER? that thing dresses up as....seems like it should be an owl or a giant Furby. <hr></blockquote><p>With the head on it, it is a hound dog.<p>[ October 27, 2004: Message edited by: paulrevelcet ]</p>

[Enzo]

Paul, the commercial foggers I am familiar with all need to warm up before they make smoke. Does yours make smoke immediately upon power up?<p>Point being we need to know if you really want to switch on power to the whole unit, or if you should plan to have it powered already and use the timer to trigger the smoke control.<p>The heater in a typical fogger uses a lot of current, while the control input uses negligible current. So a large triac works for the whole thing but a tiny reed relay or something works for the controls.<p>The 555 timer ought to work, and to protect one and all, use something like a MOC3010 to interface the timer to the triac. That is an optocoupler or optoisolator designed to fire triacs but isolate the controlling circuitry. Thus the 555 needs only drive the little LED within the opto, easy enough. The output side of the opto is wired from line to gate on the triac. The two halves of the opto are only joined by the light shining between them so there is isolation between the mains circuity and the timer circuitry.

[paulrevelcet]

Here is the link to the fogers I have foger<p>I only paid 39 dollars apiece for them they were on sale, as you can see in the photo, there is a switch that starts the pump to make fog, the switch just completes the hot side to the fog pump(which is 110), this switch is a momentary type, that is why the fogers were so cheep, (there manually activated) I have taken one apart so I am sure that is how it works, so I think if I put a triac in place of the switch and use a 555 timer configured as a one shot that is will work.<p>Now using this 555
as a reference, it shows a switch (s1) to activate the timer, since a switch is what I am trying to eliminate, I will just wire pin 2 to ground thereby eliminating the switch, then I will use a wall wart to plug into my main light circuit to power the 555, that way when I turn the light on (soon will be activated by a motion sensor) the 555 will come on and provide a pulse to the triac and start my foger, ( the heaters will stay on ) later I will add extra timing features like different pulse patterns or maybe sound activated. Is this the best way to do this? Thaks everyone.

[Edd]

Supposedly...I guess that dude can play "You ain't nothing but a hound dog" then.<p>GO FOR IT…you are 98% there when that circuit is utilized, will just have to see if that circuit initiates on power up with pin 2 that way, if not, just a little debugging of that anomaly should get it working.<p>On the simple side, that function could even be done with the utilization of a simple time out circuit that I use on my soldering stations, in order to revert to ½ power so that my tips do not oxidize away so badly. (2x) 2N2222+ (1) 2N2907+ Relay…..utilized in a Syzkli/Darlington trio with an RC timing constant.<p>That sounds like a VERY good clearance on the foggers, not that I would need one, however. Assuming that you have peeked inside how about enlightening us on the type and mechanical configuration of its heating element. As well as the fogging agent one utilizes, as well as its metering technique. The closest I would have come to this would be the insect foggers of Black and Decker. <p>73's de Edd
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<p>[ February 19, 2005: Message edited by: Edd Whatley ]</p>

[Enzo]

Oh yes, I saw those. I guess the heater stays on and the button controls the pump. You should be able to find fog juice locally at a lighting company, stage supply, of DJ equipment dealer, if you run low.<p>Remember that anything wired to that switch will be connected directly to the AC mains, and that includes your control circuits unless you isolate them. I urge you to look at my MOC3010 idea or something equivalent to isolate the timer circuitry from that triac. The timer circuit can work just fine referenced to the mains, but it represents a safety hazard if you touch any part of it.<p>We took the sound board out of an old Gorgar pinball, and powered it up and put speakers in the bushes. The beating heart noise was a great added touch. I wish I still had it. Defender and Joust sound boards are not nearly as scary.