Hello everyone, I am looking for nifty ways to upgrade my son's play kitchen, I want to make it as realistic as possible and thought a real microwave panel would do that. I am not an electronics whizz but I have some basic knowledge and am happy to learn as well. I would really like to create a simple panel that my son can press the buttons and they beep then when he presses start I could possibly get a microwave noise then a beeping after about 15 seconds is it possible to attach a light to go on and off as well? I am really not sure what path to go down with this as I am not entirely sure where to start, I came across this forum after frantically searching the internet with no joy. I was thinking about those calculator kits but they aren't exactly a fit for my needs. Here are my questions:

-Is this project actually possible? If not what should I do to tweak it?
-Is this something a newbie like me could build relatively easily? What parts would I need?
-Is this something I could ask someone to build for me? If so what would the costs be? (I am based in Germany but can receive post in the UK) or who could I ask? I was unsure of what search terms to use.
-Do you have any other suggestions for this project to make it simpler or more realistic?

Just to say in advance, I really appreciate any tips or advice, I am just a mum trying to make something nice for her little boy. Please feel free to speak as slowly as possible lol! I really am a newbie, I am always happy to learn new stuff and as much as electronics interests me it's not something I've delved into. Thank you in advance

 

Can you program? That is, do you have any software skills?

 

I'm wondering if you couldn't just hack a dead microwave on its way to the recycle dump. I mean, what you're describing sounds like a microwave with a dead magnetron. I had one of those once, and everything worked perfectly except food didn't get hot.

 

I'm wondering if you couldn't just hack a dead microwave on its way to the recycle dump. I mean, what you're describing sounds like a microwave with a dead magnetron. I had one of those once, and everything worked perfectly except food didn't get hot.

I looked at that but it needs to be quite small to go on the toy kitchen plus I wouldn't know where to start. Thanks though

Can you program? That is, do you have any software skills?

Yes I ddo have some basic programming skills. Nothing fancy but I can cobble things together.

 

An Arduino Nano or Uno can be programmed to output tones for your various effects.

There is a command, tone(), in the Arduino variant of C, that generates tones to a speaker attached to a pin.

There are 9 pins that can be used as input. The program is fairly simple, where denouncing the input pins may be the most difficult.

In your application, the debouncing can be a blocking function, which makes it easier. A search for “Arduino debounce” will result in many code examples you can use as a start.

 

An Arduino Nano or Uno can be programmed to output tones for your various effects.

There is a command, tone(), in the Arduino variant of C, that generates tones to a speaker attached to a pin.

There are 9 pins that can be used as input. The program is fairly simple, where denouncing the input pins may be the most difficult.

In your application, the debouncing can be a blocking function, which makes it easier. A search for “Arduino debounce” will result in many code examples you can use as a start.

Thank you so much for all this info, I've looked up the board but not really sure how I will turn it into what I need. Do you mind telling me what else I need and are there any examples online that will show me what I am trying to do. I just don't get how it all fits together from the board to the panel. I appreciate your time. If it is better that I go to the Arduino forum please let me know, I don't wish to be a nuisance.

 

I’d check out the Arduino forum also, but I’ll give a quick overview. I’ll mention this again later, but you’ll have many examples provided to you to help you learn. I’d also start small, with little programs to help you learn how this all works.

The Arduino comes with a USB cable which connects the uP to your computer.

You write a program (“sketch” in Arduino talk) on your computer using the free integrated development software downloadable from Arduino.

Connect a speaker, per the tone() example.

You connect as many push buttons that you need, between ground and a pin on the Arduino. On the resources tab of the Arduino site, you can learn which pins you can use and how. Initialize them in INPUT_PULLUP mode and you won’t need external resistors.

Your sketch will initialize all pins that you need. I’d also initialize serial communications, so you can insert debugging print statements to the console (included in the development software. The FREE development software).

Then in the main loop function, you test each pin you’re using and if it’s LOW, execute a few lines of code to make a sound in the speaker. This is where you’ll use one or several calls to the tone() function. You can play several tones sequentially by putting a delay() function between them.

The Arduino development environment contains sample sketch code for most functions. You can learn a lot from reading them and perhaps loading them into the Arduino and seeing how they work.

 

Just wanted to thank you for taking the time to explain and help. It's not something I'm going to pretend I've completely understood but now I have a starter and I will simply try and do my best and then I will learn things along the way. I am sure I will be back as I need to also make a heating element for his oven and I want to do this with LED lights and a rotary switch lol!

Thank you for being nice, it really means a lot. Have a lovely day.

I'm wondering if you couldn't just hack a dead microwave on its way to the recycle dump. I mean, what you're describing sounds like a microwave with a dead magnetron. I had one of those once, and everything worked perfectly except food didn't get hot.

Thanks for taking the time to answer me Wayneh. I think I'll go with djfantasi's idea but if you think the old microwave panel is easier, maybe you can clarify what I'd need to do so I can also consider it. If not, just wanted to say I appreciate your input.

An Arduino Nano or Uno can be programmed to output tones for your various effects.

There is a command, tone(), in the Arduino variant of C, that generates tones to a speaker attached to a pin.

There are 9 pins that can be used as input. The program is fairly simple, where denouncing the input pins may be the most difficult.

In your application, the debouncing can be a blocking function, which makes it easier. A search for “Arduino debounce” will result in many code examples you can use as a start.

Oh sorry can I just ask, would I be able to have an LED panel that shows the numbers with this? I assume the Arduino is a bit like a lego board and I just add the bits I need and join it all up? I will be reading through their forum tonight.

 

Here’s a skeleton sketch for the Arduino.

const int BUTTON_1 = 2;
const int BUTTON_2 = 3;
// continue for all button pins
const int SPEAKER = A0;

void setup() {

pinMode(BUTTON_1, INPUT_PULLUP);
pinMode(BUTTON_2, INPUT_PULLUP);
// continue for all button pins

pinMode(SPEAKER, OUTPUT);

Serial.begin(9600);
// used for debugging
}


void loop() {

// a simple test is all that’s
// required, as contact bounce
// is not an issue
If ( digitalRead(BUTTON_1) {
    Tone(SPEAKER);
     Delay(300);
     // or whatever you need
     // for the first sound
     }

// repeat for all buttons
}

 

Oh sorry can I just ask, would I be able to have an LED panel that shows the numbers with this? I assume the Arduino is a bit like a lego board and I just add the bits I need and join it all up? I will be reading through their forum tonight.

Some think it’s a bit like Legos, but you just can’t keep adding bits. There are restrictions...

This is a stream of consciousness post, so I apologize in advance if it gets confusing. There is a lot to consider. But I’m glad to help

It depends on the model of Arduino you choose and how many buttons you are using. Off the top of my head, the basic Arduinos have about a dozen digital pins and a half dozen analog pins. you’ll need one analog pin for your speaker, one pin for each button (in this simple design) and one pin for each LED.

With several LEDs, you may start to go over the current capacity of a pin or the Arduino. Then, I’d add BJT or MOSFETs to drive the LEDs and minimize the current needed from the Arduino. More complicated hardware design. But doable.

You want to show numbers? Like a 7 segment display? If the numbers don’t need to change, then 1 pin per number will work if the specified segments are connected to ground with their own current limiting resistor. You’d still require a BJT or MOSFET for each digit.

If you want the numbers to change, that could require 7 pins for one number, leaving you with five buttons. Then getting more complicated, you could multiplex several digits, but that would further complicate making sounds. You could use a shift register, but that would increasingly complicate programming and hardware design.

How are you going to power this?

BTW, a simple burner application would be to wire differing valued resistors to the rotary switch contacts, connecting them to the burner LEDs. But determining the resistor values might take some experimentation. How many LEDs do you plan for each burner? Red LEDs approximately have a Vf of 1.7V. You would have to wire them in series and leave some headroom in the voltage total to insert resistance to control current and brightness. Note brightness versus current is not linear, so you couldn’t switch in 100, 200 or 300 ohms and expect the brightness to change linearly.

Another approach would be a second Nano. I believe they have four special pins for Pulse Width Modulation (PWM). Instead of a rotary switch, a potentiometer could be used as an input to an analog pin on the Arduino, and depending on the value, you set the PWM value. There are functions to do this. The analogRead() returns 0-1023 depending on the potentiometer setting, the PWM function, analogWrite() takes a value from 0-255 and the map(myVal,0,1023,0,255) converts between the two ranges.

 

[QUOTE="djsfantasi, post: 1348734, member: 81714".[/QUOTE]

You know this reminds me of when I did graphic design, people think it's just a case of moving a few pictures around but it's just so much more than that.

This is clearly FAR more complex than I thought (eek!)

What I am after is literally a microwave panel with numbers 0-9 and a start button. 0-9 should beep when pressed and start should play the microwave sound for about 15 seconds then ding. I was hoping to get the numbers to show as they were pressed but I guess this doesn't matter if it's so complex. Instead then maybe I should simplify it and go for maybe 3 buttons like defrost, cook, and start? I want the panel to be able to stick or screw onto the Ikea Duktig microwave. Does that make what I am asking for clearer? I really had no idea that something that I took to be relatively simple was so complex, my respect for you electronics guys just tripled and it was already pretty darn high!!

 

My approach had been to simplify so that you will be successful.

So, let’s look at this another way First, can you live without the numbers showing?

Second, how many TOTAL buttons do you envision. And more importantly, how many different sounds?

What I’m getting at is if the buttons from 0-9 all make the same sound, they can be wired in parallel, connected to one pin and that pin is used to make the “button pressed” sound in the sketch.

This way you are minimizing the number of pins you need.

Accepting buttons and displaying them is a medium level difficulty, but there is a lot to consider.

Note that I’m not stuck on a Nano. An Arduino Mega has many more pins (50?) but costs a lot more.

Also, as you become more familiar with the Arduino, perhaps you could add an LCD display. This can display pretty much anything at a cost of a few pins and some programming. Something like this used two analog pins and can control up to five push buttons as well with their software library. You’ll have to learn how to add a library into the development environment. https://www.adafruit.com/product/772

While I’m at it, a benefit of the Arduino is there are many, many add-on products made for it. Most have their own library of functions and come with sample code. For example, you can get a standard keypad with 12 push buttons that only use 7 of your Arduino pins. Look here:
https://www.adafruit.com/product/3845

 

Thanks for taking the time to answer me Wayneh. I think I'll go with djfantasi's idea but if you think the old microwave panel is easier, maybe you can clarify what I'd need to do so I can also consider it. If not, just wanted to say I appreciate your input.

On my microwaves, all of the control and interface (sound, lights, etc.) are in one rectangular area roughly the size of, and right behind, the touch panel, and are maybe 1-2" thick. The rest of the volume of the microwave is the enclosure, the magnetron and other stuff that wouldn't need to be part of your project. I had a microwave die from a failed magnetron and that means it did everything perfectly except actually cook. I gather this is a very common way for microwaves to fail.

A big negative of my approach is that it's mains powered, so you'd need to have a good enclosure to ensure safety. Or, you might replace the power supply. The PCB and all that you want internally, are running on DC. If you could figure out how to substitute a battery, that would eliminate the mains connection.