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Stupidly simple circuit question - answered. Answered

OK, so I accidentally volunteered to make an X-factor type buzzer board for a school event.

Three switches.  Throw each switch, in any order, a light comes on.

Throw the third switch, in any order, and a buzzer and/or fourth light comes on.

It's a simple circuit.  Must be.  Just a few transistors, LEDs and batteries.

But, I just cannot work it out!

I should be able to sketch it out in my sleep, but my brain will simply not cooperate.

I'd prefer to use a single DC power supply, up to 12V (multiple LEDs to make the lights brighter), but I have several I can use if required.

Dimensions are not important, I'll just change the lengths of wires.

But, can you help with the circuit?

>K<

Thank you, Lemonie!




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lemonie
lemonie

11 years ago

Right, I've never watched X-Factor, but I think you want:
Each of three switches to light their own light independently.
All three switches to power a buzzer / 4th light?
Get three double-pole double throws, and wire like this.

L

temp.bmp
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Lithium Rain
Lithium Rain

Reply 11 years ago

>gives lemonie a vicious kick for coming up with a better idea and schematic before I was about to post another<


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Kiteman
Kiteman

Reply 11 years ago

I was all ready to go for a set of self-latching relays...

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Lithium Rain
Lithium Rain

Reply 11 years ago

I made it all pretty, with a three way AND gate and everything.

>mourns<

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Kiteman
Kiteman

Reply 11 years ago

Hey, you can still post it, especially if it's all pretty.

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Goodhart
Goodhart

Reply 11 years ago

I have to agree with Jayefuu here too;  without something like a 555 timer, you will have to reset the buzzer manually, or reset everything to cut the buzzer, since it is latching. 

If the switches trip the timer (monostable multivibrator) which trip the buzzer, you can set the duration of the buzz time.
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Jayefuu
Jayefuu

Reply 11 years ago

Don't forget a monostable otherwise that buzzer's going to be going off FOR EVER and be really annoying :D

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whatsisface
whatsisface

Reply 11 years ago

That's a very good suggestion.

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lemonie
lemonie

Reply 11 years ago

If you want something with big red plastic single-push non-latching buttons that light-up and a master-reset, the question is still open...

L

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Kiteman
Kiteman

Reply 11 years ago

I'm now waiting to find out my budget - latching DPDT push-switches are available on ebay.


0
lemonie
lemonie

Reply 11 years ago

Ooof! Urrrgh... (ow)

L

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Derin
Derin

Reply 11 years ago

Can I recommend armor,pretty useful...

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V-Man737
V-Man737

Reply 11 years ago

Of the pop-tab-maille variety?


(Let's have a discussion about the protective quality of aluminum as medieval armor!) :-P

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lemonie
lemonie

Reply 11 years ago

That's one "age" missing from History... But the topic is around here somewhere (a person objecting to the armour on grounds of irresponsibility)

L

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Tool Using Animal
Tool Using Animal

Reply 11 years ago

Gah, beat me by 3 mins, and with a schematic too!

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lemonie
lemonie

Reply 11 years ago

I would have been a bit quicker, but I had to be sure of what the thing is supposed to do first...
DPDT - we think alike

L

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Kiteman
Kiteman

Reply 11 years ago

Egad!  The man's a genius!

I could even make that with clothes pages!

I knew it was simple, I just could not make it work in my head.

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Re-design
Re-design

11 years ago

I just have to say that the competition is getting very stiff.  Yall make a great committee.

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Kiteman
Kiteman

Reply 11 years ago

Huh?

Expand, please?

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Re-design
Re-design

Reply 11 years ago

So many people with good answers all trying to be there first.

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Lithium Rain
Lithium Rain

11 years ago

I'm a little confused by the description - you mean like this (yes,  I know it's messy, I did it in a hurry :P )?


Screenshot.png
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Kiteman
Kiteman

Reply 11 years ago

Three judges, each with a switch.

When they have had enough of a contestant, they hit a switch and a light comes on.

When the third judge hits their switch, in addition to their light coming on, a fourth event (such as a buzzer) indicates that the contestant is no longer welcome on the stage.

So - three switches, each working one light.

A fourth device gets triggered once all three lights come on (the three lights can be lit in any order).

Is that clearer?

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Rock Soldier
Rock Soldier

Reply 11 years ago

I know Lemonie already answered, but wouldn't it be easier to have switch one control a light, switch two control an other light, and switch three control a light and a buzzer? As in only switch three needs to be "switched on" for the buzzer to go off? As long as judge three goes last, it seemingly works the say way as Lemonie's suggestion.

Also, what's the school event? Talent show, spelling bee, science fair?

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Kiteman
Kiteman

Reply 11 years ago

It's a talent show, hence the X-factorisation.

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Rock Soldier
Rock Soldier

Reply 11 years ago

Ah, I see. I never watched the show, so I wouldn't know. Thanks.

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Tool Using Animal
Tool Using Animal

Reply 11 years ago

Need three double pole single throw switch.

Use one pole from each switch to actuate each light, connect the second pole of each switch in series to actuate the fourth light.

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Kiteman
Kiteman

Reply 11 years ago

Thanks!

Unfortunately, Lemonie beat you to it by three minutes.

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Lithium Rain
Lithium Rain

Reply 11 years ago

Ahhhh, much, yes. :D Thanks.

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lemonie
lemonie

11 years ago

Do you get the sense of being on the same level as students who also have homework to do this weekend before they go back...? (Like my brother who's got a load of marking to do)

I'll think

L

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Kiteman
Kiteman

Reply 11 years ago

I've got a few weeks, but I have a terrible habit of getting distracted by new projects.  I know that I have two other large projects on the horizon, plus I have a bit of a learning curve to climb at work in the next two terms.

Oh, and there's the marking...

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lemonie
lemonie

Reply 11 years ago

Marking... having a few teachers in the family: I know.

L

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Jayefuu
Jayefuu

11 years ago

Sorry, the instructables community doesn't like answering homework questions. :p

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Jayefuu
Jayefuu

Reply 11 years ago

Ok... so you need:

AND gates