LED/headphone jack/switch wiring assistance
Apr 17, 2012 at 11:01 AM Thread Starter Post #1 of 16

liquidzoo

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Hello
 
I was hoping that someone would be able to give me some pointers on how to wire up a LED and a headphone jack to a switch.
 
I'm pretty sure that I can follow http://www.instructables.com/id/How-to-Construct-a-35mm-Switch-diy/step6/null/ to wire up the jacks, and I know that I will need a 560 Ohm, 1/8w resistor to power my LED (don't have the exact specs, but I think it's 3.65vF, 10mA) on a 9V battery power supply, but what I'm not sure of is how to wire it up.  I obviously only want the LED to light up when the corresponding jack is selected.
 
As a follow up to this, is it possible to put a higher value resistor in the circuit to decrease the light output from the LED?  I don't want it to be blinding.
 
Apr 17, 2012 at 4:23 PM Post #2 of 16

brondum

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[size=10pt]Not sure what you want help too. It’s really just grapping a soiling iron and some wire and get to it, just remember that the long end on the led is plus. Depending on you have a 2 or 3 stage switcher remember that when the stick is to the left side, it's the rights side pin who gets the current. [/size][size=10pt]But i really fail to see the purpose for this :D[/size]
 
Apr 17, 2012 at 4:34 PM Post #3 of 16

liquidzoo

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Quote:
 
 
[size=10pt]Not sure what you want help too. It’s really just grapping a soiling iron and some wire and get to it, just remember that the long end on the led is plus. Depending on you have a 2 or 3 stage switcher remember that when the stick is to the left side, it's the rights side pin who gets the current. [/size][size=10pt]But i really fail to see the purpose for this :D[/size]



I need a purpose for a DIY project? :p
 
Really, it's a switch box that will take audio in and switch it between 2 different outputs.  I want the LED to light up when one of the outputs is selected.
 
I'm using a 3PDT switch (this one to be exact:  http://www.frys.com/product/2860904?site=sr:SEARCH:MAIN_RSLT_PG ) to switch between the 2 output sources.  Better than crawling behind my computer all the time (front audio ports have a really nasty whine).
 
What I'm not sure about is how to hook up the LED and power source wires to the switch.  That's what I'm asking for.
 
Apr 17, 2012 at 4:59 PM Post #4 of 16

brondum

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[size=10pt]Point taken.[/size]
 
[size=10pt]English is not my main [/size][size=10.0pt]language[/size] [size=10pt]so explaining something with a lot of non-common words is hard. Im studying as electrician so maybe i can make one tomorrow at class and upload an image, because the idea sound kind of cool.[/size]
                                                                                                                                                                
 
Apr 18, 2012 at 11:10 AM Post #5 of 16

liquidzoo

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I'd love to see a schematic if you do build one.  I had plans to put my switch box inside a cigar box, but it turns out that the wood is too thick for the 1/8" jacks and the switch (and just barely too thick for the 1/4" jack), so I need to go back to a store near my work (tomorrow, since I'm working at home today) and get a proper project box.
 
Then I just need to figure out if I want plastic or aluminum, and if aluminum how to drill the right holes...
 
Speaking of drilling holes, does anyone know the (imperial rather than metric) diameters of holes I would need to drill for 1/8" and 1/4" panel mount jacks?
 
 
Apr 18, 2012 at 6:47 PM Post #6 of 16

Yoga Flame

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Quote:
Speaking of drilling holes, does anyone know the (imperial rather than metric) diameters of holes I would need to drill for 1/8" and 1/4" panel mount jacks?
 

 
It depends on the jacks. If you know the model number, you can look up the datasheets on digikey.com or mouser.com. For panel mount jacks there is usually a bit of leeway since even if the holes are a little off the mounting nuts will cover it up.
 
 
Apr 18, 2012 at 11:33 PM Post #7 of 16

liquidzoo

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Thanks, I'll take a look.  Radio Shack was not kind enough to put the dimensions on the packaging.  I'm surprised they put the wiring diagrams on there, to be honest.
 
Next on my plate is figuring out how to wire that switch... I hooked it up: Battery+ --- LED Anode / LED Cathode --- 1.2k Ohm, 1/4W Resistor --- Battery- and it worked (seemed to be not quite full brightness, too; which is definitely what I wanted), but I can't figure out which of the poles on the 3PDT switch to hook up which wires to, and if it will work when the headphone jack is connected as well.
 
What I want is to take the source from my computer to this box and, depending on the switch position, route that sound to speakers via another 1/8" jack or to my headphones via a 1/4" jack.  When the headphones are selected, I want the LED to turn on.  In my head, it doesn't sound that tough (which is a sure indicator that I'm missing something), but I'm only a hobbyist, and the only thing electrical I've made recently are some interconnects.
 
Apr 19, 2012 at 10:15 AM Post #9 of 16

liquidzoo

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Quote:
Is this enough to help you out?
 

 
Thanks.  From what I understand of a 3PDT switch, wouldn't I connect the ground to the switch terminals as well?  There are 9 of them.  From what I can see, the input will go to the center poles (does order matter, as long as I repeat that same order on the other sides?) and the outputs would go on the sides.  Also, from what I saw in the schematic I linked earlier, the switch sides are defined when holding the switch so one of the long sides of the rectangle are up, right?
 
Sorry for the questions that may make me sound like a noob, but I am when it comes to this, and I want to make sure I do this right.
 
I think what I'm seeing on this schematic, and please correct me, is that the center poles would be left channel, right channel, and battery + (with the resistor connected here), and that the LED + would be connected to the third pole of whatever channel I want it to light up with, with the grounds soldered together (for all of the channels?) and grounded elsewhere, probably to the case itself (or the battery - ?)
 
Again, I'm a noob when it comes to this, so I want to make sure I do it right and learn as much as I can along the way.
 
Apr 19, 2012 at 12:59 PM Post #10 of 16

Avro_Arrow

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The ground for the battery that powers the LED does not have to connect to the audio circuit in any way.
Just connect the negative from the battery to the negative side of the LED
and the positive terminal of the battery to the LED resistor.
I would use a rechargeable battery.
Or maybe better yet, a small wall wart. It doesn't need to be regulated.
 
The audio grounds all connect together and not to the switch.
 
Yes, the center contact of the switch connects to the side contacts.
When the toggle is down, the center contacts connect to the top terminals
and visa-versa.
 
Hold the switch so the toggle moves up and down.
The rows are now up and down as well.
 
Maybe this will be more clear:
 

 
 
 
Apr 19, 2012 at 1:08 PM Post #11 of 16

liquidzoo

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Thank you, that does help a lot.
 
If I understand correctly, using the image that you posted, when the switch is up, the Out 2 labeled contacts would be active?
 
I'd love to find a small wall wart for this, so I wouldn't have to worry about the battery, but I'm not sure I'll be able to find one at my local store.  I will look, though.  I could always order one from online, I know, and maybe I will.  I could always use the battery while waiting for it.
 
Apr 19, 2012 at 2:36 PM Post #12 of 16

Avro_Arrow

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Check put some of the local thrift stores. Sometimes they have small electronics
and "stuff" like cables, wall worts...etc. Expect to pay $1. We have a chain here
called "Value Village", I check them out on a regular basis...I got two home theater
receivers for $10 each. I also get old computer speakers (sometimes pretty good ones)
for cheap too.
 
Yes, when the toggle is up, the bottom is active.
 
Jan 22, 2013 at 12:01 AM Post #14 of 16

liquidzoo

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Going to necro my own old thread rather than making a new one.

I got this working (there's a pic of it somewhere) but I recently had another thought on this, and I wanted some opinions.

What type of switch would I need if I wanted to make something like this switch between 3 sources? What about 4? Would that even be possible?

A second question: what would be the best type of wire to use for this? Standard buy-it-anywhere type speaker wire or something else? I used some cheap solid (I think) core wire for version 1 and could swear there was a hiss in the mix somewhere. What can I do to prevent that for take 2?
 
Jan 22, 2013 at 1:02 AM Post #15 of 16

DingoSmuggler

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Why not source you LED power over USB? This is going to be for a computer after all. (because who wants an extra wallwart plugged into their power board)
5V power will mean the LED will have about 1/3 as much current through it, so it will be about 1/3 your current brightness give or take, the LED won't mind the lower current, but if you want to go brighter you will need to reduce the size of your resistor to compensate.
 
Just snip the end off a USB cable and use the red and black wires if you want to have a "flying lead" coming from your switch box.
If you prefer using a socket rather than flying lead, pin 1 is the 5V power and the last pin is 0V ground (pin 4 for a full size USB socket, pin 5 for a mini/micro).
 

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