# Switch light on with rotary switch and dimmable LEDs

#### TogetherInElectricDreams

Joined Jan 23, 2019
48
“Dishwasher”? I missed that feature...

Recovering from the death in the family. We’ll provide a diagram soon.

I do have a moment to verbally describe what I think you need.

The first switch to the oven light is straightforward. One terminal if the switch goes to the power supply. The second is writer to the light. To prevent the “burner” LEDs from lighting unless the first light is lit, instead of wiring the switch to the power supply, wire it the the same output terminal connected to the oven light.

To use individual LEDs for the burner, they have to be wired in groups which are then wired in parallel. Using 12VDC as the supply and red LEDs with of forward voltage if 2V and current draw of 15mA, you can wire five LEDs in series with a 130Ω resistor. Note that the LED maximum current may be 20mA but it’s better to run then with a lower current. Look at the calculations:
R = (12V -5 * 2v) / 0.015A
= 2V / 0.015A
= 133 Ω​

So, depending on how many LEDs you need for the burner, try to design it so the total number is a multiple of 5.

To dim the burner, use a PWM module as suggested about. You can externally mount the potentiometer to use as a switch for the burner. Connect the PWM supply to the oven light switch for the effect you said you wanted. And connect the PWM output to the LEDs.
Sorry to hear @djsfantasi. Condolences to you and yours. Thank you for your continued help.

I won't go for individual LEDs I'll use the wire, I like the look of it as it looks most like a filament, dimming would be fun to do but isn't essential. In all electric ovens I've used you turn one switch to get the "setting" of the oven, then you turn the other dial to set the temperature, as I can't dim the LEDs what can I use that will give the same feeling OR should I just make the light switch turn on both the light and LEDs and then have a "dud" dial?

I am choosing a 2 position rotary for the light switch but it doesn't matter if it's 4 as the only two functions of the dial are on and off any "differences" will just be pictures on the dial.

Dishwasher is part of the arduino project. Let me list in full what is required:

Microwave (arduino)
Dishwasher (arduino)
Sink with working pump
Oven that glows red (nice if it dims, no worries if not)

Everything to run from one 12V "jack strip" with one wall cable.

#### TogetherInElectricDreams

Joined Jan 23, 2019
48
Some of the " parts" that have been alluded to are: microwave, dishwasher, oven, pump, sink, & stove top. All have not been addressed yet?
Is that two ovens ?
Hi Bernard,

I am taking on the task of souping up this kitchen for my son. The sink will work (pump), the oven will have dials and "work" the dishwasher (on the left) will "work" (panel with lights). The microwave will "work" as well. The kitchen comes with a working cooker. My project is four parts but as I have no understanding of electronics I've been asking for help. I didn't want to ask everything on one thread as I didn't want to burden one person with my inane questions but am trying to glean what info I can so I can go away and put it together. The microwave and dishwasher are arduino projects and as they are similar I only asked about the microwave.

#### djsfantasi

Joined Apr 11, 2010
5,577
Sorry to hear @djsfantasi. Condolences to you and yours. Thank you for your continued help.

I won't go for individual LEDs I'll use the wire, I like the look of it as it looks most like a filament, dimming would be fun to do but isn't essential. In all electric ovens I've used you turn one switch to get the "setting" of the oven, then you turn the other dial to set the temperature, as I can't dim the LEDs what can I use that will give the same feeling OR should I just make the light switch turn on both the light and LEDs and then have a "dud" dial?

I am choosing a 2 position rotary for the light switch but it doesn't matter if it's 4 as the only two functions of the dial are on and off any "differences" will just be pictures on the dial.

Dishwasher is part of the arduino project. Let me list in full what is required:

Microwave (arduino)
Dishwasher (arduino)
Sink with working pump
Oven that glows red (nice if it dims, no worries if not)

Everything to run from one 12V "jack strip" with one wall cable.
So go ahead with two switches. As I described to get the original effect, the first switch turns on the light. From the same contact connected to the light, connect that to one side of the second switch. The other side of the second switch will connect to the power supply for the EL wire.

I specifically worded it that way, because the EL wire needs to be connected to a 3V source. You will need a 12V to 3V converter for the EL wire.

So, wire the second switch to the converter. Then wire the output of the converter to the EL wire. Sounds complicated maybe, but it’s very simple!

#### Bernard

Joined Aug 7, 2008
5,254
Dimming a LED strip can also be done with a single darlington transistor, pot. & a resistor. To demonstrate I used a D1326 with a b of 2000
but there are many others depending on where you order from, 2N6388 about US $1.00, 2SD1699,$ 1.50.
Following @disfantasi lead. my string is 5 red LEDs in series & 130 ohm resistor. Pot is 5K, & R is 10K. A 120 ohm R was added to bring current up to 100 mAs . Heat sinking depends on LED string length..

#### djsfantasi

Joined Apr 11, 2010
5,577
Dimming a LED strip can also be done with a single darlington transistor, pot. & a resistor. To demonstrate I used a D1326 with a b of 2000
but there are many others depending on where you order from, 2N6388 about US $1.00, 2SD1699,$ 1.50.
Following @disfantasi lead. my string is 5 red LEDs in series & 130 ohm resistor. Pot is 5K, & R is 10K. A 120 ohm R was added to bring current up to 100 mAs . Heat sinking depends on LED string length..
Bu he wants to use EL wire...

#### Bernard

Joined Aug 7, 2008
5,254
MRS Dreams said," Or should i just make the light switch turn on both the light and LEDs and then have a dud dial ".
Doesn't look like any thing is cast in stone yet.

#### djsfantasi

Joined Apr 11, 2010
5,577
MRS Dreams said," Or should i just make the light switch turn on both the light and LEDs and then have a dud dial ".
Doesn't look like any thing is cast in stone yet.
But in the same paragraph that you quoted, the following statement was made...

I won't go for individual LEDs I'll use the wire, I like the look of it as it looks most like a filament, dimming would be fun to do but isn't essential..
Earlier in the thread, there was some confusion between EL wire and LEDs. The TS made a statement that indicated he conflated the two different products.

But as you can see, using EL wire is cast in stone. He “won’t go for individual LEDs.” He’ll “use the wire”.

#### Bernard

Joined Aug 7, 2008
5,254
Should there be any concern on 90 -120 V AC operation of the EL wire ?
For Microwave some throbbing LEDs or EL wire might look good ?

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#### djsfantasi

Joined Apr 11, 2010
5,577
Should there be any concern on 90 -120 V AC operation of the EL wire ?
What 90-120VAC operation? Where are you getting these ideas?

He was running everything from a 12VDC 5A bus, last time I checked. Plus, he’s been informed that the EL wire only runs on 3VDC and to use a voltage converter module on the 12V bus to drop the voltage to 3V.

#### Bernard

Joined Aug 7, 2008
5,254
From the net it seems that there are converters for EL wire with inputs from 3 V, 2 AA batteries, 12V, up to line operation with outputs of 90 - 120 V AC, with frequencies from 400 , most in 1k range up to 10k HZ. The higher the frequency the brighter with a penalty of shorter life.
Each switched EL light will need a converter.

#### djsfantasi

Joined Apr 11, 2010
5,577
Ok, I misunderstood what you were saying. Sorry. He is planning on ordering a certain EL wire device, which is a package deal, inverter included and which runs on 3 AA batteries.

#### Bernard

Joined Aug 7, 2008
5,254
Enlighted Designs, EL wired costumes, " You can receive a mild shock from the end of a piece of EL wire. " They no longer carry EL wire.
I have never had any EL wire, but to me a shock hazard seems quite low if cut ends are properly terminated and cable is not roughly handled.

#### Bernard

Joined Aug 7, 2008
5,254
In looking for EL controls, found an obsolete Arduino EL Shield, Seeed Technology Co Ltd. PN: 104030000, which gives dimming control for four EL devices with added EL converter. So EL wire is dimmable? Wish that I had a sample of wire.

#### djsfantasi

Joined Apr 11, 2010
5,577
In looking for EL controls, found an obsolete Arduino EL Shield, Seeed Technology Co Ltd. PN: 104030000, which gives dimming control for four EL devices with added EL converter. So EL wire is dimmable? Wish that I had a sample of wire.
Yes, it’s dimmable, but not by controlling current nor voltage. EL dimmers work by changing the frequency of the power supply.

#### Bernard

Joined Aug 7, 2008
5,254
The EL shield Post 33 uses one external EL converter for four controled EL devices & mentions PWM so it doesn't seem that frequency is the determining factor. Need more information.

#### Bernard

Joined Aug 7, 2008
5,254
THE sink kitchen unit has battery operated surface burners, two red rings. Faucet is non operational , handle turns. Sink has no drain . MIght use a buck converter to replace the batteries ? Should there be a master switch on the 12 v wall adapter?

#### djsfantasi

Joined Apr 11, 2010
5,577
The EL shield Post 33 uses one external EL converter for four controled EL devices & mentions PWM so it doesn't seem that frequency is the determining factor. Need more information.
Old news... The fact that PWM doesn’t work with EL wire but rather frequency was discussed with him previously. Also, all the other information about batteries, buck converter and a 12V adapter was discussed and he agreed on a 12VDC bus...

What’s confusing is that the TS has multiple threads on this one project and issues resolved in one are not apparent in the others, so people are pointing out issues that long since have been resolved.

Or not! With so many active threads, there is no continuity to the discussion. What I think is resolved may reappear in another thread. It’s impossible to track the discussion time line when it’s spread over a half dozen threads.

#### Bernard

Joined Aug 7, 2008
5,254
Mrs Dreams, OP. TS, is still peeking in. A progress report would be nice. How is the EL wire working?