Wiring LEDs to Corresponding Switches?

Condo B

Nov 3, 2017
12
I am looking to wire a lot of 12v LEDs to a lot of LED switches. Each light up switch would light up a single corresponding LED and all would be powered by the same power source preferably. Can anyone help me map out a circuit set up for this? I am making a prop for a film and need the help of an expert!

dorke

Jun 20, 2015
2,342
Welcome to EP.
How many are a "lot"?

kellys_eye

Jun 25, 2010
6,225
It's the same process as wiring one LED to a switch.

Power supply, switch, resistor, LED. Repeat ad-nauseum.

Power supply is whatever voltage you require and (xLED multiplied by its operating current - usually 20mA) rated.

i.e. for 100 LEDs running at 20mA you will need (100 x 0.02A) = 2 amp power supply at whatever volts.

The resistor you use will depend on the voltage you choose.

May 6, 2017
193
Yep

dorke

Jun 20, 2015
2,342
Nop guys !

For 100 LEDs you should use a matrix !
That will simplify everything by the order of squrae root of the number of LEDS!

Last edited:

Condo B

Nov 3, 2017
12
Welcome to EP.
How many are a "lot"?
I have about 30 12v LEDs connected to pushbuttons with LEDs inside of them which each require about 5v of power each.

Condo B

Nov 3, 2017
12
It's the same process as wiring one LED to a switch.

Power supply, switch, resistor, LED. Repeat ad-nauseum.

Power supply is whatever voltage you require and (xLED multiplied by its operating current - usually 20mA) rated.

i.e. for 100 LEDs running at 20mA you will need (100 x 0.02A) = 2 amp power supply at whatever volts.

The resistor you use will depend on the voltage you choose.

So with amperage I add up the amps used throughout the circuit? With voltage do I do the same or do I take the highest voltage used? For example I have about 30 12v LEDs connected to 30 pushbutton LEDs that require about 5v each.

Last edited:

kellys_eye

Jun 25, 2010
6,225
The power supply in your example would be 12V - and you'd need a current capacity of 30 x 20mA which is 600mA so a 1A power pack would be fine.

To drop the 12V to the LED voltage (which varies depending on the chosen colour - around 1.6V for red and up to 3.6V for white) you need to pick the correct current limiting resistor using the formula:

R = (Vsupply-Vled)/Iled where Vsupply is your chosen power pack, Vled is the LED forward volt drop and Iled is the recommended LED current.

e.g For a red LED this would be (12-1.6)/0.02 = 520 ohms (560 ohms is the nearest preferred value).

e.g For a white LED this would be (12-3.6)/0.02 = 420 ohms (470 ohms being the nearest preferred value).

Note that the voltage and current values need to be taken from the manufacturers data sheet to get a precise answer although you'd come to no harm (and neither would the LEDs) if you just used 560 ohms regardless of the colour!

BobK

Jan 5, 2010
7,682
Are you saying that you have 30 12V LEDs and 30 switches with 5V LEDs inside?

Bob

Jun 25, 2010
6,225

Nov 3, 2017
12

kellys_eye

Jun 25, 2010
6,225
You are adding complications at each and every post by not being fully advisory with your requirements.

You now show LED-lit buttons along with LEDs you want to light........ I presume you want the buttons to light when the button is pressed AND the attached LED to light at the same time?

Condo B

Nov 3, 2017
12
You are adding complications at each and every post by not being fully advisory with your requirements.

You now show LED-lit buttons along with LEDs you want to light........ I presume you want the buttons to light when the button is pressed AND the attached LED to light at the same time?
My apologies the prop I am making just needs lights to be going on and off when an actor is pressing it, I believe one of the kinds of push buttons stays lit all the time, which is fine, the second (arcade button) flashes on it's own, and the last (square push button) turns on and off with the light when pressed. All these functions are fine for my project, All I am looking to do is power the buttons and the LEDs and be able to wire a circuit to a singular power source so that when the actor starts pressing the buttons, their corresponding light turns on and off, meanwhile the buttons are lit the way they were made, flashing or staying on.

Audioguru

Sep 24, 2016
3,650
Since ebay knows nothing about electricity, the current required by the button LEDs is not stated. I went to the manufacturer's site but there is no part number box there.
I think the cheap Chinese switches have a current rating that is much too high at 25A then they will fail (tarnish and corrosion) with the very low current of the LEDs.

I did not look at the sales sheets for all the switches to see if any of them stay on when pressed then switch off when pressed again.

Condo B

Nov 3, 2017
12
Since ebay knows nothing about electricity, the current required by the button LEDs is not stated. I went to the manufacturer's site but there is no part number box there.
I think the cheap Chinese switches have a current rating that is much too high at 25A then they will fail (tarnish and corrosion) with the very low current of the LEDs.

I did not look at the sales sheets for all the switches to see if any of them stay on when pressed then switch off when pressed again.
Interesting couldn't find the current rating either, the small push button from adafruit stays on while the larger arcade button from adafruit blinks. The square button from ebay turns on and off when pressed.

kellys_eye

Jun 25, 2010
6,225
Regardless.

You still need to know the total current requirement OR you get a power supply that you know will have sufficient current capacity based on the average requirement for ONE LED/switch combo multiplied by the max potentially in use.

Using 'worst case' of 100mA per LED and 20mA per (illuminated) switch you want a PSU of 12V and (x * 120mA).

30 lights/switches? = 30 * 0.12 = 3.6A

I'd suggest you get a 12V 5A power pack and leave it at that. All circuits (switches and LEDs) wire in series and each set of switch/light wires in parallel.

It would appear that all the devices you show operate from 12V without the need for series dropper resistors but if there are items requiring 5V then I suggest you get an old PC power pack (internal or external) with 12V and 5V available from them at much more current than you'll ever use!

Fit a fuse in series with the 12V and 5V outputs - say 5A fuse - and play to your hearts content!

Condo B

Nov 3, 2017
12
Regardless.

You still need to know the total current requirement OR you get a power supply that you know will have sufficient current capacity based on the average requirement for ONE LED/switch combo multiplied by the max potentially in use.

Using 'worst case' of 100mA per LED and 20mA per (illuminated) switch you want a PSU of 12V and (x * 120mA).

30 lights/switches? = 30 * 0.12 = 3.6A

I'd suggest you get a 12V 5A power pack and leave it at that. All circuits (switches and LEDs) wire in series and each set of switch/light wires in parallel.

It would appear that all the devices you show operate from 12V without the need for series dropper resistors but if there are items requiring 5V then I suggest you get an old PC power pack (internal or external) with 12V and 5V available from them at much more current than you'll ever use!

Fit a fuse in series with the 12V and 5V outputs - say 5A fuse - and play to your hearts content!
Thank you! When you say "All circuits (switches and LEDs) wire in series and each set of switch/light wires in parallel." What would this wiring look like? Are you saying wire the overall all LEDs in series among the switches and each individual LED switch is also wired in parallel?

kellys_eye

Jun 25, 2010
6,225
supply + ---- switch(in) switch(out)---- LED(+) LED(-)---- supply 0V. <---- this is a series circuit.
.
.

repeat the above for all the switches/LEDs you have
.
.

connect all the supply + together and all the supply 0V together <---- this is the parallel circuit.

Individual switches that have their own built-in lighting will require power to their LED pins taken from the switch(out) side and the other side of the LED taken to 0V.

Condo B

Nov 3, 2017
12
supply + ---- switch(in) switch(out)---- LED(+) LED(-)---- supply 0V. <---- this is a series circuit.
.
.

repeat the above for all the switches/LEDs you have
.
.

connect all the supply + together and all the supply 0V together <---- this is the parallel circuit.

Individual switches that have their own built-in lighting will require power to their LED pins taken from the switch(out) side and the other side of the LED taken to 0V.
Thank you for your insight this is helping me a TON, would this look something like my drawing when it is wired? (obviously there will be more switches and LEDs in the final circuit)

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