Hello all, I am in need of some guidance with my current project. I am building a play kitchen for my two girls as a Christmas gift, but I am wanting to make it unlike any other. My plan is to make the "appliances" as realistic as possible, with illuminating burners, oven element, microwave and fridge lights, etc.

The problem I have run into is how to make the "burners" illuminate on the stove top. The stove is designed to be a flat surface range, with 12V LED flex tube lights nestled into burner drip trays mounted beneath a sheet of plastic to mimic the glow of the stove top burners. However, I have not been able to find a solution for how to achieve this.

From the several forums I have read it seems that potentiometers tend to give off heat, significantly in some cases, and I may not be able to turn the lights off completely. So my question to this community is how do I go about making a play stove with "burners" that can be shut off completely, and gradually brightened WITH knobs, like a normal stove, but without requiring significant voltage and current, or other potentially hazardous side effects?

Any and all help is greatly appreciated, and I will follow up with a completed project post once this baby is done! The frame is built but I want to have the electrical completely figured out before I go much further with this. Thanks in advance!

 

If you post a link to the LED tube lights you put in there we can suggest a more specific solution to dim the LEDs. How much current they draw is a factor to what will be used to control them.

A quick Amazon search you could get these. I'm sure there is a cheaper solution to find but this does have an off position.

https://www.amazon.com/Volt-Dimmer-...1478664579&sr=8-2&keywords=12V+LED+dimmer#Ask

There are other pre made LED controllers out there. Some larger some smaller. Do you have a size constraint?

 

I don't know how "12V LED flex tube lights" are powered but here is how I would do it.

Get the following components:

12VDC adapter (100 to 500mA is sufficient), only one required for the whole project

For each burner:
about 6 red LEDs
100Ω 1/2W resistor
2kΩ 1/2W potentiometer with ganged on/off switch
knob for the potentiometer
22awg hook-up wire

The rest is easy. Don't be afraid to ask if you need instructions.

Edit: change 2kΩ to 5kΩ or 10kΩ

 

If you post a link to the LED tube lights you put in there we can suggest a more specific solution to dim the LEDs. How much current they draw is a factor to what will be used to control them.

A quick Amazon search you could get these. I'm sure there is a cheaper solution to find but this does have an off position.

https://www.amazon.com/Volt-Dimmer-...1478664579&sr=8-2&keywords=12V+LED+dimmer#Ask

There are other pre made LED controllers out there. Some larger some smaller. Do you have a size constraint?

Thanks for your reply! I found some 5V flexible led tube lights as opposed to 12V, here: https://www.aliexpress.com/item/1M-...ar-Decor-Light-Neon-LED-lamp/32700296601.html I think these would work better, or something similar, but this should give you an idea of what I will be working with. Thank you for the link to the dimmer, something I should have mentioned in my original post is that I live in Canada so most Amazon.com products don't ship here, which is the case with the product you linked. As for size constraints, I am currently fairly unrestricted, as all I have done so far is the skeletal framing, and the knobs will be mounted horizontally on the front of the stove top so bringing it out to accommodate longer hardware is an option. I am considering bringing an arduino board into the mix since I can get the same lights in 5V, which I believe should be easier.

 

I don't know how "12V LED flex tube lights" are powered but here is how I would do it.

Get the following components:

12VDC adapter (100 to 500mA is sufficient), only one required for the whole project

For each burner:
about 6 red LEDs
100Ω 1/2W resistor
2kΩ 1/2W potentiometer with ganged on/off switch
knob for the potentiometer
22awg hook-up wire

The rest is easy. Don't be afraid to ask if you need instructions.

Hi, thanks for your help! The lights I had originally planned to use are powered with a detachable 12V car-lighter socket adapter, but I have found similar lights for much cheaper that are powered with a 5V USB supply. I am leaning more towards this option now. In the case of the 5V USB LEDs, what resistance rating will the potentiometers need? I think that by using an arduino board and variable resistor potentiometers, I can use some code to control the brightness at each available setting, so I am leaning more towards this solution. I have a great understanding of circuit board logic, as well as some intermediate coding abilities, but I have limited experience with creating electrical circuits from scratch such as a project like this requires so I appreciate your help, thank you!

 

I think it would be better to go with a 12VDC adapter.

Go with 5kΩ (preferred) or 10kΩ pot 1/2W

(+)12VDC -> ON/OFF SWITCH on pot -> 100Ω resistor -> center pin on pot
clockwise pin on pot -> anode LED1 cathode -> LED2 -> LED3 -> LED4 -> LED5 -> anode LED6 cathode -> 12VDC return (-)

 

I think it would be better to go with a 12VDC adapter.

Go with 5kΩ (preferred) or 10kΩ pot 1/2W

(+)12VDC -> ON/OFF SWITCH on pot -> 100Ω resistor -> center pin on pot
clockwise pin on pot -> anode LED1 cathode -> LED2 -> LED3 -> LED4 -> LED5 -> anode LED6 cathode -> 12VDC return (-)

I will explore this as an option and weigh it into consideration. The reason I am leaning more toward the arduino implementation though is because I have a couple Uno R3 boards and enough breadboard, jumper wire and everything else to make a 5 node I2C system, with an Uno master and 4 additional nodes behind the potentiometers. This way I can give each position on the potentiometer a numerical value that corresponds to the voltage to be sent to the lights. I will have to experiment and compare the two options. Thanks again for your input!

 

I will explore this as an option and weigh it into consideration. The reason I am leaning more toward the arduino implementation though is because I have a couple Uno R3 boards and enough breadboard, jumper wire and everything else to make a 5 node I2C system, with an Uno master and 4 additional nodes behind the potentiometers. This way I can give each position on the potentiometer a numerical value that corresponds to the voltage to be sent to the lights. I will have to experiment and compare the two options. Thanks again for your input!

The 5V lights you linked to, i'm confused, is it EL wire or an LED strip? It says both in the description. It may be EL wire. If that's the case it not a matter of a potentiometer to a 5V supply anymore. EL wire requires an AC current. I guess you can cut the USB wire and try to PWM the 5V input. If it's LEDs, there can only be at max two LEDs in that strip because the input is 5V and each RED LED will have about a 2V drop. My guess is that it is EL wire since it looks like it has a control box in series with the USB cable. I guess it could have a DC to DC inverter in there to power LEDs. But I don't know.

And if it is just LEDs, you can put an analog in to your Arduino for the potentiometer, but you can't just put PWM from the MCU pin directly to your LED strip it's too much current. You will need to put a transistor to supply the current and the MCU PWM will control it. And you still will want a resistor to make sure the current does not get too high.

 

The 5V lights you linked to, i'm confused, is it EL wire or an LED strip? It says both in the description. It may be EL wire. If that's the case it not a matter of a potentiometer to a 5V supply anymore. EL wire requires an AC current. I guess you can cut the USB wire and try to PWM the 5V input. If it's LEDs, there can only be at max two LEDs in that strip because the input is 5V and each RED LED will have about a 2V drop. My guess is that it is EL wire since it looks like it has a control box in series with the USB cable. I guess it could have a DC to DC inverter in there to power LEDs. But I don't know.

And if it is just LEDs, you can put an analog in to your Arduino for the potentiometer, but you can't just put PWM from the MCU pin directly to your LED strip it's too much current. You will need to put a transistor to supply the current and the MCU PWM will control it. And you still will want a resistor to make sure the current does not get too high.

Thanks for your reply, I didn't notice the contradiction in the product description. It seems it is in fact EL wire, but this may actually work out in my favor. If I set up an I2C network between dedicated slaves for each pot that sends data to a single master, and an additional slave for the EL wires using an EL shield, I believe it could be easily managed with a little crafty code. This way, the master would essentially just request and relay data between the slaves, leaving it relatively freed up.
When I began this project, I definitely underestimated this particular aspect of it, I really did think it would be as simple as a few wires and a battery pack with some pots to control the brightness. I am grateful for the help received and am eager to hear what you think of my I2C network solution. I have everything necessary to make up to 6 breadboard arduinos, plus I have 2 genuine boards and 3 clones so I have more than enough resources to do this. I am in the process of making up the schematic in Eagle and will upload files when I have this completed. This is the link for the EL shield on ebay: http://www.ebay.ca/itm/EL-Shield-Mo...052802?hash=item1a015d7942:g:BZsAAOSwpdpVeH83

 

Thanks for your reply, I didn't notice the contradiction in the product description. It seems it is in fact EL wire, but this may actually work out in my favor. If I set up an I2C network between dedicated slaves for each pot that sends data to a single master, and an additional slave for the EL wires using an EL shield, I believe it could be easily managed with a little crafty code. This way, the master would essentially just request and relay data between the slaves, leaving it relatively freed up.
When I began this project, I definitely underestimated this particular aspect of it, I really did think it would be as simple as a few wires and a battery pack with some pots to control the brightness. I am grateful for the help received and am eager to hear what you think of my I2C network solution. I have everything necessary to make up to 6 breadboard arduinos, plus I have 2 genuine boards and 3 clones so I have more than enough resources to do this. I am in the process of making up the schematic in Eagle and will upload files when I have this completed. This is the link for the EL shield on ebay: http://www.ebay.ca/itm/EL-Shield-Mo...052802?hash=item1a015d7942:g:BZsAAOSwpdpVeH83

Sounds like a fun project. I've been wanting to play with EL wire myself. Wanted to make a tron suit for Halloween. If that's what you want to do I say go for it.

It does sound like a lot of work for what you are trying to do. But if it's for fun then there is no such thing. As a backup you can get this LED strip

https://www.superbrightleds.com/mor...ble-led-rope-lights/2959/#/tab/Specifications

With this controller:
https://www.superbrightleds.com/mor...12-24-volt-dc-single-color-led-dimmer/62/365/

All pre-made and the controller has a dial that you can use for the oven knob or attach a real oven knob to it somehow.

Or you can do what Mr. Chips said and make it simple.

 

Another simple solution is to use a 4-position rotary switch to select four positions, OFF, LOW, MED, HIGH.
Use three different resistors.

OFF - open (no resistor)
LOW - 1kΩ
MED - 470Ω
HIGH - 100Ω

Experiment with different resistance values to obtain the desired brightness.

 

The 5V lights you linked to, i'm confused, is it EL wire or an LED strip? It says both in the description. It may be EL wire. If that's the case it not a matter of a potentiometer to a 5V supply anymore. EL wire requires an AC current. I guess you can cut the USB wire and try to PWM the 5V input. If it's LEDs, there can only be at max two LEDs in that strip because the input is 5V and each RED LED will have about a 2V drop. My guess is that it is EL wire since it looks like it has a control box in series with the USB cable. I guess it could have a DC to DC inverter in there to power LEDs. But I don't know.

And if it is just LEDs, you can put an analog in to your Arduino for the potentiometer, but you can't just put PWM from the MCU pin directly to your LED strip it's too much current. You will need to put a transistor to supply the current and the MCU PWM will control it. And you still will want a resistor to make sure the current does not get too high.

Thanks for your reply, I didn't notice the contradiction in the product description. It seems it is in fact EL wire, but this may actually work out in my favor. If I set up an I2C network between dedicated slaves for each pot that sends data to a single master, and an additional slave for the EL wires using an EL shield, I believe it could be easily managed with a little crafty code. This way, the master would essentially just request and relay data between the slaves, leaving it relatively freed up.
When I began this project, I definitely underestimated this particular aspect of it, I really did think it would be as simple as a few wires and a battery pack with some pots to control the brightness. I am grateful for the help received and am eager to hear what you think of my I2C network solution. I have everything necessary to make up to 6 breadboard arduinos, plus I have 2 genuine boards and 3 clones so I have more than enough resources to do this. I am in the process of making up the schematic in Eagle and will upload files when I have this completed. This is the link for the EL shield on ebay: http://www.ebay.ca/itm/EL-Shield-Mo...052802?hash=item1a015d7942:g:BZsAAOSwpdpVeH83

Another simple solution is to use a 4-position rotary switch to select four positions, OFF, LOW, MED, HIGH.
Use three different resistors.

OFF - open (no resistor)
LOW - 1kΩ
MED - 470Ω
HIGH - 100Ω

Experiment with different resistance values to obtain the desired brightness.

I am definitely liking this idea! After some schematic drafting and tinkering with boards, I have decided that the I2C network idea is way overkill for a project like this. It has inspires some future project ideas, but as for this one I am thinking I will go with your suggestion here. I have yet to decide on the lighting, but when I do I will play around with the resistances until I have something like what you have suggested. I have ordered the rotary switches from ebay and will update this thread when I have more progress to share or additional questions. Thank you guys very much for your help!

 

So, after several months it comes time to update and ask for further help in this project! This was originally supposed to be built as a Christmas gift for my daughters, but due to work and moving, and a few other road blocks that never happened. I finally got the opportunity over the last week to begin assembling this play kitchen. I have tinkered over the months trying to get the circuit right, and for a while I thought I had it! Until now, as it is time to install everything into the frame and complete the assembly, the circuit I made no longer seems to be working. So let me give a run down:
I am using a 12V rechargeable Li-ion battery as the power source. I have the 12V drivers for the EL wire which I connect to 12V, and the collector of an 2N2222 transistor. The emitter is connected to ground, and the base is fed through a 1K resistor by a 10K potentiometer. The potentiometer is getting ~5V DC from an LM7805 voltage regulator IC that is also using the 12V Li-ion source, and is directing that to the transistor base. Essentially I am trying to use the transistor as a switch to completely disable the EL wire drivers' connection to ground, and this switch is controlled by the potentiometer. I am not exaggerating when I say I have constructed this circuit DOZENS of times on breadboard, trying to get the desired result of EL wire that will dim with the adjustment of the pot, and completely shut off at some critical position. I have had it working every time up until now, and I cannot explain why!!! I am in desperate need of some guidance! Should I abandon the LM7805 altogether or could this be due to the fact that this time around I am using much longer lengths of wire? All help is greatly appreciated!

 

Here is an iCircuit schematic of what I have going on. The only thing not shown is the EL wire driver, which is placed between the 12V source and the collector of the transistor (red to 12V, black to transistor). I used the 7805 because the breakdown voltage between the base and emitter of the 2N2222 is something like 6V if I remember correctly. Using my multimeter I usually read just under 1V at the base when the pot is maxed one way, and 0V when maxed the other way. I'll be honest here, I never once picked up a pencil to actually figure out resistances or anything, just figured 10K pot would be "good enough", and a 1K resistor to ensure there is always some current restriction. Another oddity I stumbled across while probing with the multimeter is that I cannot seem to get anything but a big fat "0.00" when testing the current, even when testing leads directly connected to the battery. Why is this and could this be my issue?

 

Hi, I need help with my EL wire circuit. I have 5 one meter lengths of EL wire, each with a 12V driver. I am using an 2N2222 as a switch to completely disable connection between the EL wire driver and ground. I am using a 20,000mAh 12V Li-ion battery as the source. The EL wire driver sits between the 12V source and the collector of the 2N2222. The emitter of the transistor is connected the battery's "-", and the base is fed through a 1K resistor by a 10K pot which is connected to the output of an LM7805 voltage regulator IC. The 7805 is also powered by the 12V battery but has an independent ground. I have built and tested this circuit numerous times before but for some reason it will not work now that I need it to (it is for a play kitchen project for my kids). I have checked every connection, replaced every component (2N2222, 7895, EL driver, resistor, breadboard AND pot) in case something was faulty but to no avail. I've probed with my multimeter and the voltages are on the ball, but there is no current according to my meter. I am tapping out and asking anybody for help with this, it is beyond me at this point why it will not work this time, after having worked flawlessly several times before. The ONLY difference between previous tests and the current configuration is that I am using longer lengths of wire this time between the potentiometer and respective connection points. I've included an iCircuit schematic of what I have going on. The only thing not shown in the schematic is the EL wire driver which sits between the 12V source and the transistor collector. Thanks to all in advance for any and all help!!!

 

If you have connected your multimeter directly across the battery with it set to the current range you will have probably blown an internal fuse or damaged the meter. The 6 volt base emitter breakdown voltage of the 2N2222 is for when the base is negative of the emitter. In your circuit you will only be driving the base positive of the emitter so you only need to limit the base current. (Say 25 mA max) It behaves like a forward biased diode so the base emitter voltage in that direction will be a maximum of about 0.7 volts. Until I saw your posts I had not heard of "EL wire" I found that it requires quite a high voltage (90 to 120 volts AC at abot 1 Khz) so it probably will not meet your safety requirments. Varying the input voltage to the inverter will probably not give a linear control of brightness. The inverter will probably stop working when it's input voltage gets below a certain level. Have you checked that the EL wire with it's inverter still works connected directly to the battery ?

Les.

 

The 7805 is unnecessary in your set-up. Without it the maximum base current would be <12mA.

 

Your 7805 may be oscillating, as it doesn't have the input and output caps shown in the datasheet. But the 7805 isn't needed anyway.

 

Hello,

The ground pin of the 7805 is not connected.
As drawn, the transistor will short the 12 Volts powersupply.

Bertus

 

There are many things wrong with your approach, already mentioned by members:

1. Your meter very likely has a blown fuse. You need to learn the proper procedure for measuring current with a test meter.
2. The LM7805 regulator is unnecessary.
3. The way your circuit is drawn, the transistor will blow.