New idea, but not sure if this can be done easily - Page 1
Forum section: electronics / beginners

author: diane
author_rank: Newbie
timestamp: February 24, 2019, 02:22:58 pm
content: Hi, I am new to this forum, but I really have an important question on how to build on a new idea. I am thinking of safety and some convenience. My idea is to add a small cooling fan toward the lower end of a microwave to help cool down over heated food. Many people put dishes that are not supposed to go into a microwave and because of that, the dish is too hot to touch. Many people could burn themselves. Another thing that seems to happen is that the food should only cook for less than a minute and for some reason, the person cooks the food 3 minutes; therefore burning it or creating a very hot dish of food.The idea came from my elderly mom that lives in an assisted living place. She has a microwave and has done both. How can I build something like this using most of what is already supplied within, but of course adding a small fan for cooling. I would also have to connect a new button for its use. Thanks and I do need help. diane

author: Lord of nothing
author_rank: Super Contributor
timestamp: February 24, 2019, 02:36:54 pm
content: I use some Tupperware like this but in Blue:The Food get well temperate. So how do you want cool them?The best thing is when people understand how a micrwave work.

author: Audioguru
author_rank: Super Contributor
timestamp: February 24, 2019, 06:42:20 pm
content: I think it is obvious that if an old person cannot use an appliance properly then they should not have that appliance. The same goes for my 1.5 years old grandson.

author: helius
author_rank: Super Contributor
timestamp: February 24, 2019, 06:54:43 pm
content: It's a good thing that you're thinking of ways to solve people's problems: all engineering comes from that instinct. However, you should understand that certain devices contain dangerous components, and are designed according to standards and regulations to reduce the risk they present to users. A microwave oven is such an appliance, because it is 1) a high-power device connected directly to mains electricity (120 or 240 volts); 2) an emitter of powerful, invisible radiation, that needs to be shielded from the user. If you make modifications to the sheet metal or wiring of a microwave oven, you may compromise the protections and nullify safety certifications, and lose insurance coverage if they lead to fire or injury.

author: magic
author_rank: Super Contributor
timestamp: February 24, 2019, 08:26:15 pm
content: QuoteSafety certifications and insurance, you Westerners are killing meThere is nothing wrong with nullifying certifications as long as the government which imposes them doesn't find out (which implies nobody was harmed in the process).The first and foremost problem is that if you puncture the internal shielding and let the microwaves escape, you are going to enjoy all sorts of fun ranging from your WiFi breaking down up to cooking all the meat in your kitchen, including yourself. And that may be worse than voiding your oven's certification.Also, you can't simply put an electric fan inside because electronics don't really work well in that kind of environment.I'm sure it can be done, see the rotating plate at the bottom if in doubt. But I wouldn't have a clue how to do it safely and probably few people actually have a clue.

author: Lord of nothing
author_rank: Super Contributor
timestamp: February 24, 2019, 08:40:02 pm
content: With a new product you can make the circulating around but only if the food not in a closed container.Most effective is when someone put some spoons of water into the container.

author: StillTrying
author_rank: Super Contributor
timestamp: February 24, 2019, 08:45:12 pm
content: Acoolingfan in a microwave, sounds like a bad idea.Microwaves contain4 KillerVolts.

author: helius
author_rank: Super Contributor
timestamp: February 24, 2019, 08:56:46 pm
content: The problem of not knowing how long to set the microwave timer is more or less a universal one. It's been an issue since the first machines were sold in the 1960s, and various approaches have been tried to solve it. One of the first was the thermometer probe:https://www.chicagotribune.com/news/ct-xpm-1985-09-26-8503050474-story.htmlThis was a thermocouple probe (or RTD) that plugs into a socket inside the oven and is placed in the food. The oven turns off according to a programmed temperature setting (or a required time above some temperature). These have gone out of fashion and are rarely seen today, in part because a wired thermometer won't work with a rotating carousel tray.Other methods include detecting humidity inside the oven to tell when the food has reached a boil. There is, unfortunately, no general foolproof system to detect cooked or overcooked food. An infrared temperature sensor looks like the best approach, but it can be fooled by different materials: a clear polyethylene food wrap is opaque to infrared.

author: Richard Crowley
author_rank: Super Contributor
timestamp: February 24, 2019, 09:01:45 pm
content: There are microwave ovens with temperature probes that you poke into the food. Presumably to limit or otherwise control the heating energy.I wonder whether they could fit an IR sensor into the top of the interior space to sense the temperature of the food. At least in crude way to shut off in case of overheating. Of course, it might be a problem defining what "overheating" means. Especially for different kinds of foods.As for heating up the containers, you could just have them use paper plates, bowls, etc. I just slide the paper plate out of the microwave onto a room-temperature plate to avoid burns.

author: hagster
author_rank: Frequent Contributor
timestamp: February 24, 2019, 09:17:24 pm
content: Microwave oven + Thermal Camerahttps://youtu.be/ptkzzNaZb7U

author: metrologist
author_rank: Super Contributor
timestamp: February 25, 2019, 07:07:18 pm
content: The first thing that sprung to mind was an infrared camera and a smarter controller. Then you could install a magnatron array and modulate them to form nodes/modes right where you need them.

author: macboy
author_rank: Super Contributor
timestamp: February 25, 2019, 07:26:41 pm
content: Look into using the auto-reheat function built into most decent microwaves. Essentially, it heats the food until steam is generated then stops.

author: metrologist
author_rank: Super Contributor
timestamp: February 25, 2019, 09:39:31 pm
content: That might answer a question I had - a newer microwave I disassembled had two sensors. They had a flat steel mesh like a speaker grille, one mounted to sense between the walls and the other mounted to sense inside the oven. Maybe they are detecting humidity? I'd want to repurpose them.

author: helius
author_rank: Super Contributor
timestamp: February 25, 2019, 10:02:32 pm
content: Some microwaves have a microphone for only one purpose: to detect the bag of microwave popcorn is fully popped.

author: metrologist
author_rank: Super Contributor
timestamp: February 26, 2019, 03:22:27 pm
content: LoL, that's brilliant, actually.

author: tooki
author_rank: Super Contributor
timestamp: February 26, 2019, 03:48:52 pm
content: Quote from: diane on February 24, 2019, 02:22:58 pmA fan big enough to counteract the heat being pumped into the food would have to be quite large. That, together with all the other reasons already mentioned, make this idea a non-starter.May I suggest some low-tech options, like an oven mitt and a tray? I sometimes use a larger, known-safe plate to go under dishes that I know tend to overheat in the microwave. Corelle/Arcoroc tempered glass dishware works really well, as it’s a relatively poor thermal conductor, so doubled-up plates let the lower plate stay comparatively cool.

author: diane
author_rank: Newbie
timestamp: March 06, 2019, 12:54:39 am
content: I want to thank all who replied. I am very serious about this subject. Safety is very important. I would like to see this type of microwave produced by a manufacturer. I also put a patent out for the idea. What people may not realize is there are billions of senior/assisted homes being built because of all the older baby boomers. These places usually start at 4 to $5000 a month. Senior living is great, but when it becomes time for assistance, all things change. Assisted living apartments only allow microwaves. I know 80 and 90 year old people cannot read instructions or even see all of the fancy buttons. I believe manufacturing a safer microwave and selling these by the bulk, is a big money making opportunity. I also worry about my mom. We had to place masking tape on the buttons she can use.

author: sambonator
author_rank: Regular Contributor
timestamp: March 06, 2019, 01:35:28 am
content: I suppose you could add gears to the carousel mechanism to drive a small fan under the turntable with vents that blow air under your plate.EEVBLOG (Electrical Engineering VBLOG) is probably not the best place for those kinds of ideas. You may want to find a mechanical engineer to work with on your project.

author: tooki
author_rank: Super Contributor
timestamp: March 06, 2019, 03:24:22 am
content: Quote from: diane on March 06, 2019, 12:54:39 amWhile your goal may be admirable, I don't think you've thought this through very well. A good mental exercise to do is to ask not why you should do something, but instead to ask yourself "Why hasn't this been done before?"Combination microwave-fridge units are already commonly made for college dorms. (Why? Because they need a mechanism to shut off the fridge when the microwave is running, to prevent overloading the circuit and tripping the breaker.) So there clearly are already manufacturers who specialize in "institutional" appliances. Why haven't they gone after this market, then?So let's see why they might not be making these. Here's me brainstorming, in no particular order:1. is this actually a market big enough to go after?2. is the target audience of elderlywho struggle with ordinary microwavesas big as you think it is?3. is there no microwave on the market that solves some or all of the problems?What's the competitive landscape?4. is it technically feasible to build such a device?5. if you can build it, what new problems could it cause?6. is there actually money to be made?7. today's 90 year olds struggle with microwaves because they didn't grow up with them. Boomers have been using microwaves for most of their lives. Will they actually struggle to use an ordinary microwave once they are seniors?Let's look at each of these.1. Yeah, I think it could be, given that even a small percentage of seniors already mean potentially millions of sales, maybe a few hundred K per year.2. Probably not.3. Well, you've raised several issues. One issue is confusing controls — but there do exist microwaves with simple mechanical timers and no modes. There are also ones (commonly used in commercial kitchens, cafeterias, etc) that have only a few buttons, which are custom-programmed to specific recipes. The other issue is wanting it to monitor for overtemperature. I don't think that's feasible. Temperatures high enough to be food-safe are high enough to scald, period.4. Simple controls? Sure. Temperature monitoring? Difficult — accurate monitoring of the internal temperature of foods has vexed established microwave makers for decades. But even if you could monitor internal temperature well, it's literally impossible to make food hot enough for safety and yet keep the food cool to the touch.5. Food safety: if you don't heat food to skin-scalding temperatures (~160F), it's not hot enough to ensure food safety. So a microwave that refuses to heat to a scalding temperature is going to be a risk for food poisoning, which the immune systems of the elderly are extra susceptible to. IMHO, this makes this concept a non-starter.6. Doubtful, in that microwave ovens are now low-cost, low-margin commodities. I have no doubt you could makesomemoney, but given the comparatively low volumes of such a niche product, you'll be pricing it higher than a mainstream model of similar capabilities and quality, thus reducing the number of buyers.7. I don't think so. If you've lived most of your life using regular microwaves, you'll likely continue to do fine with most ordinary microwaves, provided the buttons and displays aren't too small.So, not trying to piss on your parade, just some food for serious thought. Given how many companies specialize in assistive products for the elderly, it's worth serious thought as to why they haven't done this already. Lest you put all your savings into this and then have it go nowhere…If you ask me, a better idea might be to market microwave cookware that's designed to stay cool to the touch and provides large, arthritis-friendly handles (à la Oxo Good Grips).

author: jmelson
author_rank: Super Contributor
timestamp: March 06, 2019, 04:48:47 am
content: Quote from: tooki on March 06, 2019, 03:24:22 amYup, I think Tooki has got it right! Don't fix the microwave (technically hard, requires certification and expensive testing, might not work in all circumstances, etc.) but fix the cookware! That sounds MUCH easier, just some smart industrial design and molding the right plastic or ceramic to the right shape. We have some cookware that gets really hot in the microwave (hotter than the food!) and others that stay cool. Obviously some difference in the material.Jon