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flippityflop

timer to trigger latch

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Just looked at the last circuit with two transistors.

Whn the power is applied C2 will charge causing the horrizontal transistor (I'll call it Q2) to turn on. The vertical transistor (I'll call it Q1) will then turn on  as C1 will charge. The relay will be activated shorting out C2. When C1 is fully charged, Q1 will turn off, de-energising the relay causing it to open.

The only wat to reset the circuit is to press the start then the on reset or the reset then quickly press the start before C2 recharges.




cool. so it works glitch-free, then, huh? and after the whole cycle (after it shorts the control and turns itself off), the whole circuit absolutely doesn't draw any more power, right?

btw, is there any way to lower the voltage to just about 3-5V?? i'm thinking of only using rechargeable batteries, you see.

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Here is what I came up with


cool. it's just that i really don't have a clear grasp of the theory. so, you'd have to explain to me why and how much better this one works. although i think you forgot that i wanted to start the timer after i pressed a second button.

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press push button 1 and it switches the time delay control circuit on. for practical purposes, the high capacitance capacitor for the electromagnet will always be in parallel (ON) with the source, so that no charging time is needed.

press push button 2 and it starts the time delay circuit. 1, 2, 3... :
1) shorts the high capacitance circuit through the electromagnet coil, snapping the hinged mechanism.
2) turns off the control circuit.

the device may be turned on again with push button 1.



the "high capacitance capacitor", above, when shorted, is what supplies the power for my external electromagnetic coil; snapping a hinged mechanism.

i know i sounded non-sensical. i tend to do that every once in a while.  ;D

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You win I give up!!!! ??? ??? :o :o :-[ :-[


it wasn't a competition. i wouldn't have come here if i knew the answer.

other than that, i have a question about latching push button switches... do they usually go back to being open after the power through them has been cut-off?

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You didn't help us to help you much in the first place by not making your requirements clear. In future, post drawing, schematics, graphs and charts and you'll get the answer you were looking for much more quickly.

To be honest, I'm still not sure whether the circuit 'you've designed will meet your requirements but if you build it and it works then I'd be very happy for you.

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alright... the intent of my device, though it sounds silly,  is this:
http://www.canadiantire.ca/AST/browse/6/Tools/WeldingSoldering/AccessoriesRodsWire/PRD~0580037P/Lincoln%252BElectric%252BAutodark%252BFlame%252BThemed%252BWelding%252BHelmet.jsp?locale=en

i can't cough up that much for some auto-darkening thigamajig.... though i like the idea very much. it should give me enough time to position my 2 hands before i make the contact when i'm arc welding.

so i thought that if i bought a simple welding goggles for about $10, maybe i can attach an electronic mechanism to it that. so when pressed, should give me enough time to position my hands (though it'll require a bit of practice). 1, 2, 3 then it'll snap down the dark lens and i can make the electrode come into contact.

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You're paying all that money for one good reason: safety. It's designed to be reliable so it doesn't fail exposing you to harmful cancer causing UV radiation.

The product you've linked to seems like good value for money, it will be guaranteed to reliably and safely filter dangerous UV radiation.

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can't find a proper latching switch that goes to being open after the power has been cut-off (reset?). so i changed the design on parts that i can easily obtain.


i'm not really sure with it. i have these 2 unknown component that are lock-off devices -- if current goes to the gates, it OPENS, BUT it has to do it EVEN IF THERE IS NO CURRENT FLOWING THROUGH THE ANODE AND CATHODE YET AND MAINTAIN IT FOR AT LEAST 7-10ms ... though i haven't actually heard of such a device.

and i'm trying to discharge C1 so for the next cycle it'll work glitch free, and that discharge should also keep the current going so as to let 5ms pass and completely switch the latching relay.

i wanted to change the N/O DPST relay to a solid state device... (a FET, maybe???), one that is still small. what's the lowest voltage that this control circuit can operate reliably (6-9 V??)

i've also omitted the diodes that protect the relay, hope that's ok.


parts that needs consideration:
C1 = 47uF to 220uF

latching DPDT relay:
http://www.nteinc.com/relay_web/pdf/R72.pdf

latching push button (still not final, it's too big):
http://www.galco.com/scripts/cgiip.exe/wa/wcat/itemdtl.r?listtype=&pnum=AB6H-A1-R-IDEC

N/O DPST relay:
http://www.nteinc.com/relay_web/pdf/R74.pdf

the fictional unicorn-like components ?? (1) and (2):
what are they and can i get them small and cheap?



post-44241-14279144319754_thumb.png

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like i said, it's silly


So why not just buy it? If you spent the amount of time you've spent trying to come up with an inferior design yourself working you'd have the money to buy it by now.

Anyway for educational purposes I'll take a look at what you want.

So you need the output to go high after 15 seconds from pressing the button and remaining on until the button is pressed again. The easy way of doing this would be to simply program a microconteroller but you could use a flip-flop and a timer.

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If you spent the amount of time you've spent trying to come up with an inferior design yourself working you'd have the money to buy it by now.


unfortunately, money is an issue and buying that $150 thing is too much of a luxury.

and, no, i have not spent weeks coming up with these things -- though saying that might not be a good thing, as it automatically suggests that. it's what i read-on and scour the web (for parts) when i'm bored or can't sleep.... or something. so it really is something that i don't prioritize, more like afterthoughts; as are other projects that i've started almost a year ago that still ain't done...

with the exception of my programming projects, that is.

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I don't know, you drew the circuit. They look like SCRs to me.

Seriously, use a microcontroller, the PIC12F508 could easilly do what you want or better still save up or take a bank load to buy the propper welding mask.

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I don't know, you drew the circuit. They look like SCRs to me.

Seriously, use a microcontroller, the PIC12F508 could easilly do what you want or better still save up or take a bank load to buy the propper welding mask.


yep just looked the little bugger up... it's tiny.

but, i don't want to add another task in my to do list, that is, to learn to program PICs... and i don't have a PIC programmer  ???. i also have no experience at all to wiring microcontrollers.. (i'm not even that sure as to what pull-up resistors does).

at least my last design has the functionality of being adjusted manually and it turns itself off (huh!! take that!).

just ordered my parts lists online (still don't know what to use for the unknown component) whole thing cost 15 frickin dollars. that's shipping not yet included. ridiculous.

post-44241-14279144328231_thumb.png

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yep just looked the little bugger up... it's tiny.

What do you mean? It comes in a through hole DIP which is the same package as a 555 timer, uA741, LM393 etc.


don't want to add another task in my to do list, that is, to learn to program PICs... and i don't have a PIC programmer  ???. i also have no experience at all to wiring microcontrollers.. (i'm not even that sure as to what pull-up resistors does).

It's not hard to learn, especially if you program in BASIC.

at least my last design has the functionality of being adjusted manually and it turns itself off (huh!! take that!).

With an MCU that can be done in software without any need to change any comkponent values and the delay can be controlled pretty accurately so there's less experimentation.

just ordered my parts lists online (still don't know what to use for the unknown component) whole thing cost 15 frickin dollars. that's shipping not yet included. ridiculous.

You could bought some PIC12F508s and a cheap USB programmer for mot much more than that or saved even more money by making your own parallel port programmer.

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What do you mean? It comes in a through hole DIP which is the same package as a 555 timer, uA741, LM393 etc.


i wasn't sarcastic when i said that.

anyways this discussion's gone too long than it need be. locking it now.

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i wasn't sarcastic when i said that.

I know, I disagree, it's not small at all. The PIC12F508 comes in a large through hole DIP8 which can easily be soldered to strip-board. You can get it in smaller surface mount SOIC8 package which is still easy to solder, compared to the tiny DFN8 package which is only 3x2mm.

anyways this discussion's gone too long than it need be. locking it now.

Unlocked, you shouldn't be allowed to do that, it's a bug in the forum software.

Moderator

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