Will 5v to the ground... EE help with RGB Topfire... see post #22

[Bender]

I know it's an odd question but.. I need to share the common from a RGB LED with a button, and the LED common caries the 5v from the LEDWiz
Will that 5v to the ground loop hurt micro switches or an encoder?

sorry in advance for lack of basic electrical knowledge

Edit: ok I've been thining about this a bit more(which is probably a bad thing) so if the switches' NO(normally open) connection doesn't connect back to the LEDWiz then the 5v won't be transmitted, is that right?

[matsadona]

I'm not sure I follow you on this one, nor do I understand what you are trying to accomplish.
Could you please draw a basic scheme of you idea and explain what your goal is?
Then there are plenty of people besides me around here with a wast knowledge in electric circuits that will help you do it right.

[DaOld Man]

To echo matsadona,
draw us a pic!

[ChadTower]

Well it's safe to say 5v isn't going to hurt a microswitch any.  The rest of it probably won't hurt the encoder but might produce some awfully odd results.

Use a separate ground if they are separate circuits.

[Vigo]

I'm still trying to see any reason for routing a LED through a encoder ground. Are you trying to save wire, or is there a functional reason? (i.e. Trying to get the led to flash when the button is pushed)

I also agree with Chad's assesment, those microswitches can easily take a 5v direct current, and it probably wouldn't damage the encoder, but I don't think you would get the results you want since you are grounding one circuit out on another circuit. I would just recommend avoiding the whole thing.

[BobA]

Bender
Are you trying to light and LED by grounding it via the same switch that sends the signal to your encoder.  There was a thread on this and several circuits.  I think that the simplest was just using the same ground thru the switch.  Sorry cannot find it right now but if I remember correctly it worked and Andy even said that it would not hurt the inputs of the ipac.

[NickG]

this is a pretty good way
http://shoryuken.com/content/light-up-activation-button-mod-tutorial-61/
if you only have a couple of button activated lights you can do this with some diodes, but hex inverters are better for more, and easier to work with on stripboard.

[BobA]

Found the link for a simple hookup to light LED buttons.

LED buttons light when pressed

[Bender]

ok I should have posted this earlier
I'm not trying to get the light to blink when pressed (but if that is the only solution that is ok)
I'm trying to make a topfire RGB light-up joystick
I am using a 4pole 3.5mm jack and plug in the bottom of the shaft to allow for the shaft to spin and as Stubs suggested in another thread
I'm using the shaft itself as a 5th pole, but I need 6 poles 4 for the RGB and 2 for the button, so I though I could share the common, but that turns out not to be so easy
The Diagram I have above does not work
If I detach the common from the mini pac the lights work, but the button doesn't
If I detach the common from the LEDwiz the button works, but obviously no lights
Is there any way to do this with 5 poles?

[BobA]

Your problem looks to be that you are try to put both 5V and GND thru the shaft.   If you changed the LED to a common cathode it could share a ground but then the LED wiz would not work unless the output circuit could be changed to to handle common cathode.  Maybe an inverter circuit?

[Bender]

If you changed the LED to a common cathode

how would one do that?

[Popcorrin]

If you changed the LED to a common cathode

how would one do that?

They sell common cathode led's, but like BobA said, you run into the problem with the LED Wiz then. 

[Popcorrin]

What might be the easiest is run 5 volts up your orange wire and then when you press the button it would send 5V down your black wire which would then go to a 5v relay or a transistor to close the circuit for button 1.

[Popcorrin]

Here's an altered pic.  After thinking about it though, a relay might not be responsive enough, probably better to use a transistor.

[Bender]

if I used a 5v transistor how would I wire it, it's got 3 contacts right?
Please explain as you would I child... a slow dim-witted child




I think this is the right diagram for a transistor switch
how would I wire the B,C,E to my setup?

ok I think my black wire goes to C, E to the ground and B to the encoder button 1?
do I need a resistor between B and the encoder? am I even close?

[DaOld Man]

I think using an opto-isolator to replace the relay in popcorrin's circuit would be by far the easiest and cheapest way to do this.

Edit:
Does the led wiz have a ground on it? If so the led of the opto isolator needs to connect to it. (pic posted)

[Bender]

Transistor no good? I already got one of those

Yes the LEDWiz does have a ground

more quick and dirty please

seriously more quick and dirty pics (nice already done)

What size resistor?
what kind of opto-isolator?

[DaOld Man]

This might work

[Bender]

sorry to be so dim, could you label the BCE on the transistor
Can't thank you guys enough

oh yeah, and what size resistor

[DaOld Man]

Im not real sure about resistor size, maybe 1000 ohms?
Before you do this, make sure that both devices, led wiz and minipac, have the same power supply ground feeding them.
Both supply grounds need to be negative. And there should be no voltage between them.
If you are feeding both from a 5 vdc power in your computer, you should be ok.
I just dont want to see you fry something expensive.

I still think opto isloator would be the best way to go with this.
Both circuits would be isolated from each other.

Also:
With the transistor, you may have to add another higher value resistor from base to emitter to prevent mis-fires.
This "bias" resistor would pull the base to ground, to keep it turned off until the + 5v is applied via the pushbutton.

[Bender]

OK lets go the opto-isolator route

what kind, and what size resistor would I need for that circuit

[DaOld Man]

Well I would use a til119 opto isolator, just because I happen to have a few extras.
The resistor for this baby (at 5 volts) would be around 300 ohms.
The led of the til119 is good for 20 ma easy, so, E/I=R or 5/0.020 = 250 ohms, but  250 to 330 will work just fine.

Edit:
 I forgot to  account for led voltage drop, which is around 2 volts, so formula for resistor would be 5-2/0.020 = 150,
so better make it a max 200 ohm resistor.

[Bender]

After I saw a picture of something similar I messed around and came up with this and it works, How come?
Am I going to fry anything?

EDIT: OK... not so fast seems like I fried the Red LED, oh well worked for a few minutes

[DaOld Man]

I dont know, I dont see how it is working, unless the two devices have isolated grounds. maybe??
I mean, I see how the mini pac is getting its button fired, but whats going to happen when the ledwiz turns on the red wire going to the led and the button is pressed at same time?
But if it works, what can I say?

[Bender]

well it doesn't work, I fried the red LED the one the button was hooked to, coincidence I think not

opto-isolator to the rescue...

I need to learn some patience

[DaOld Man]

Dang the bad luck. Opto is on the way.

[Skullreaper2000]

I may not be an expert at this but should it not be something like this

[Bender]

I may not be an expert at this but should it not be something like this

Skullreaper thanks for the info!

This seems to work
anybody see anything unsafe about this set up?

EDIT:Not quite, I didn't notice a faint red glow in my initial test it seems that the red LED is picking up he current from the mini pac button line so the red LED is on faintly all the time

Alright I'm not messing with this anymore
DaOld Man gave me a perfectly good and safe solution(as well as the parts!, thanks man) I'm going with that.
Bender out!