Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

A Linux-powered microwave oven

lwn.net

Post reply on HN
Print view View original

31–40 of 65 posts

Re: A Linux-powered microwave oven

#31

Post by trymas »

jahnu wrote: post #26
Sanddancer wrote: post #4

Linux on a microwave feels a lot like the NetBSD toaster from all those years ago. Additionally, it doesn't make sense from a technical perspective. People have converted toaster ovens to do smd reflow with an arduino [1], and that requires a lot more delicate control of temperature and timing; hell, Linux is worse for the job because its realtime capabilities are so poor. Also, if you're going to go through the trou…

Can anyone here explain to me why microwave ovens always have their power settings as multiples of some value, e.g. 200/400/800w but never have the ability to set a specific power output, e.g. 425w.

Microwaves with turning knobs (example [0], maybe not the best, but you'll get the point) can have arbitrary power setting.

My personal, electronic microwave, has values 125/250/500/750W so not completely exponential (I guess, that's what you meant?).

One thing is, you can always (?) set arbitrary time, so you can compensate to gaps in power settings.

Other thing, maybe electronics are more simple with power settings like these?

When I see exponential settings I would always think of analogy to photography and 'f-stops' [1]. Some devices have exponential settings due to the physical nature of something, but is it the case with microwaves, I don't know.

[0] http://www.firstiraq.com/sites/default/files/products/5002-1...

[1] https://en.wikipedia.org/wiki/F-number

Re: A Linux-powered microwave oven

#32

Post by rainforest »

jahnu wrote: post #26
Sanddancer wrote: post #4

Linux on a microwave feels a lot like the NetBSD toaster from all those years ago. Additionally, it doesn't make sense from a technical perspective. People have converted toaster ovens to do smd reflow with an arduino [1], and that requires a lot more delicate control of temperature and timing; hell, Linux is worse for the job because its realtime capabilities are so poor. Also, if you're going to go through the trou…

Can anyone here explain to me why microwave ovens always have their power settings as multiples of some value, e.g. 200/400/800w but never have the ability to set a specific power output, e.g. 425w.

At a total guess it's down to the lack of precision in the output at anything other than full power. Most (all?) microwaves just pulse the magnetron to achieve an average delivery of the rated power so the difference between 400W and 425W would be dependent on the time the microwave runs, given most tend to use a fairly long time period.

You can see this effect if you run a microwave on low power for a short period - sometimes the magnetron will be running for the full duration.

Re: A Linux-powered microwave oven

#33

Post by kuschku »

testerooooooo wrote: post #19
andrewclunn wrote: post #12

This was really just done so that Richard Stallman could eat popcorn again without going into a rant. Nobody tell him that the genes for the corn it's made from are likely proprietary.

He should only eat GPL'ed popcorns.

Actually, there are universities doing genetic research on corn that have published some variants under free licenses.

So he might actually be able to eat corn under GPL license.

Re: A Linux-powered microwave oven

#34

Post by zapu »

bcook wrote: post #27
adrianN wrote: post #18

Earlier quoted context omitted.

That's the standard interface for microwaves for me.

My standard interface is a finicky touchpad. Has been for ~30 years & half a dozen microwaves.

This is one that I've bought this year: http://www.elektrogeraete-co.de/bilder/produkte/gross/434738...

Not a crappy brand, a mid-range product I think. Costs around 180 EUR here.

Re: A Linux-powered microwave oven

#35

Post by zapu »

ggoss wrote: post #6
chipperyman573 wrote: post #5

Earlier quoted context omitted.

>Then again, the buttons on my microwave are also so horrible Is it really that hard to push "Time cook -> 2 -> 3 -> 0 -> Start"? I mean come on I can understand wanting to optimize your life or whatever but complaining about microwave buttons seems a bit ridiculous.

For the record, many of the microwaves I've used have required something more like "Time cook -> 2 -> 2 -> 2 -> 3 -> 0 -> 0 -> 0 -> Start -> Facepalm" than the intended "Time cook -> 2 -> 3 -> 0 -> Start". TL;DR: pressing buttons is easy, but sometimes they press your buttons back.

My previous one had something like, e.g. "Cook > Power > 500W > Time > 15 sec > 15 sec > 15 sec > Start" for cooking something for 45 seconds at 500W. None of my guests knew how to use it, because pressing buttons in wrong order would do nothing (not even error "beep").

Re: A Linux-powered microwave oven

#36

Post by jahnu »

trymas wrote: post #31
jahnu wrote: post #26

Earlier quoted context omitted.

Can anyone here explain to me why microwave ovens always have their power settings as multiples of some value, e.g. 200/400/800w but never have the ability to set a specific power output, e.g. 425w.

Microwaves with turning knobs (example [0], maybe not the best, but you'll get the point) can have arbitrary power setting. My personal, electronic microwave, has values 125/250/500/750W so not completely exponential (I guess, that's what you meant?). One thing is, you can always (?) set arbitrary time, so you can compensate to gaps in power settings. Other thing, maybe electronics are more simple with power settings…

Yeah I was wondering if it was analogous to transformers where you have multiple coils all wound together and you combine them in various ways to get different voltages.

I have almost no idea how a magnetron actually works.

Re: A Linux-powered microwave oven

#37

Post by dmd »

zapu wrote: post #34
bcook wrote: post #27

Earlier quoted context omitted.

My standard interface is a finicky touchpad. Has been for ~30 years & half a dozen microwaves.

This is one that I've bought this year: http://www.elektrogeraete-co.de/bilder/produkte/gross/434738... Not a crappy brand, a mid-range product I think. Costs around 180 EUR here.

That's gorgeous. It would be laughed off the market here in the US. Where can I buy one?

Re: A Linux-powered microwave oven

#38

Post by testerooooooo »

kuschku wrote: post #33
testerooooooo wrote: post #19

Earlier quoted context omitted.

He should only eat GPL'ed popcorns.

Actually, there are universities doing genetic research on corn that have published some variants under free licenses. So he might actually be able to eat corn under GPL license.

Like I was joking or something...

Re: A Linux-powered microwave oven

#39

Post by crispyambulance »

Sanddancer wrote: post #4

Linux on a microwave feels a lot like the NetBSD toaster from all those years ago. Additionally, it doesn't make sense from a technical perspective. People have converted toaster ovens to do smd reflow with an arduino [1], and that requires a lot more delicate control of temperature and timing; hell, Linux is worse for the job because its realtime capabilities are so poor. Also, if you're going to go through the trou…

Yes, it sort of makes me think of the infamous Espresso machine on kickstarter a few years back (https://www.kickstarter.com/projects/zpmespresso/pid-control...). They raised a ton of money for a "hackable" PID-contolled espresso machine starting from 5+ years ago, then delay after delay after delay....

The thing is, kitchen appliances are HARD. Appliance designers spend careers doing the stuff and have manufacturing know-how and are backed by serious resources. A dude installing linux in a microwave is going to have a good time and perhaps get other folks excited and I am all for that (and have done ghetto-retrofits myself).

But there are good microwaves out there, they just cost more than others. If you just want a good microwave and want to encourage better designs, fork over the money and buy them! On the other hand, it is just a microwave. There are better ways to cook food... don't overthink it!

Re: A Linux-powered microwave oven

#40

Post by crispyambulance »

IshKebab wrote: post #20
xenonite wrote: post #13

Earlier quoted context omitted.

Hi! Maybe you know of any oven that is using [2] or similar? I would like to buy one. Thank you.

The 250W transistors cost £100 each. You probably need a few of them for a microwave. A microwave with these in would cost at least £1k. Probably more, so I think it will be a while.

It will be a while, yes. The price will plummet as soon as a heavy starts selling products with these components.

Looking at NXP's "RF Cooking" page, it appears they're pushing this stuff with some optimism... (http://www.nxp.com/video/sage-freescales-vision-of-an-intell...)

Post reply on HN