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MacRumors
Sep 22, 2008, 12:44 PM
http://www.macrumors.com/images/macrumorsthreadlogo.gif (http://www.macrumors.com)


http://images.macrumors.com/article/2008/09/22/134304-equiv.jpg

Tuaw takes a look (http://www.tuaw.com/2008/09/22/first-look-equivalence-for-iphone/) at Equivalence [App Store (http://phobos.apple.com/WebObjects/MZStore.woa/wa/viewSoftware?id=284971265&mt=8)] for the iPhone. Equivalence is a conversion tool "for engineers" designed by one of our forum members (http://forums.macrumors.com/member.php?u=108472).

Besides converting over 260 different units, the app also has an auto-update system so it can add new units and make changes over-the-air rather than waiting for an App Store update. Other features listed by the developer include:

Easy-to-use basic mode for simple conversions similar to most popular conversion utilities
Advanced mode allows for freeform conversions involving any combination of units
Powerful and thoroughly tested expression processing engine to ensure your results are calculated quickly and accurately
Unit Morpher converts your result to your desired resultant units
Library of common physical constants for easy input
Scrolling fields accommodate long expressions and results
Multiple pages of common units accessible from the keypad

TUAW concludes that this is the best unit converter for the iPhone. The app is priced at $4.99 and is available in the App Store: iTunes Link (http://phobos.apple.com/WebObjects/MZStore.woa/wa/viewSoftware?id=284971265&mt=8).

Article Link (http://www.macrumors.com/iphone/2008/09/22/equivalence-conversion-utility-for-engineers/)



lowbatteries
Sep 22, 2008, 02:01 PM
Doesn't this duplicate some of the functionality of calculator? Perhaps it got approved because it can also be a flashlight?

Seriously, it looks like a pretty handy tool.

Rybold
Sep 22, 2008, 02:03 PM
Doesn't this duplicate some of the functionality of calculator?

Awesome! It's much more than just a calculator. It keeps track of your units for you. I am a scientist, and I will use this so I don't have to do all the unit conversions on paper anymore. Plus, I can also use it just as a reference for conversion factors. There is still a lot that must be written on paper though. But $4.99 ! ???? I'll have to think about that. For $2.49, it would be "sold!," but $4.99 ? I can still use the charts we have on the lab walls and in textbooks.

Update... upon looking at the links, this is MUCH more than just a calculator. This thing is pretty cool. It literally keeps track of the units in your answer! Sweet! :D If you type in 5 Nm2/s2 times 4, it will return an answer of 20 J. Nice!

mainstreetmark
Sep 22, 2008, 02:26 PM
Awesome! It's much more than just a calculator. It keeps track of your units for you. I am a scientist, and I will use this so I don't have to do all the unit conversions on paper anymore. Plus, I can also use it just as a reference for conversion factors. There is still a lot that must be written on paper though. But $4.99 ! ???? I'll have to think about that. For $2.49, it would be "sold!," but $4.99 ? I can still use the charts we have on the lab walls and in textbooks.

Update... upon looking at the links, this is MUCH more than just a calculator. This thing is pretty cool. It literally keeps track of the units in your answer! Sweet! :D If you type in 5 Nm2/s2 times 4, it will return an answer of 20 J. Nice!

Plus, the difference between $4.99 and $2.49 can be made up for by skipping the diet coke next time you get a big mac.

(why does *everything* have to end in .99?)

AustinZ
Sep 22, 2008, 02:47 PM
It's a great app. By the way, the TUAW linked site has an update that states that the app will be on sale for $1.99 for a couple of days, so it's definitely worth checking out if you have a need for a unit converter.

arn
Sep 22, 2008, 03:34 PM
It's a great app. By the way, the TUAW linked site has an update that states that the app will be on sale for $1.99 for a couple of days, so it's definitely worth checking out if you have a need for a unit converter.

I think the sale is over.

arn

aka.gus
Sep 22, 2008, 04:00 PM
Actually I think the sale's supposed to last until Oct 6th, but there's no sign of it in the Swedish store (costs SEK38 which is roughly USD 5.99...).

Sbrocket
Sep 22, 2008, 04:01 PM
I think the sale is over.

arn

Nope, its just starting. :)

Equivalence will be $1.99 (as soon as the AppStore page updates with the new price) until October 6th, celebrating the release of its third update.

If anyone here has questions about it, I'll be happy to answer them either here or you can fire me an email - dev[at]apogee-dev[dot]com. There some more information about it at my site, as well - http://apogee-dev.com/.

DipDog3
Sep 22, 2008, 07:32 PM
Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 2_1 like Mac OS X; en-us) AppleWebKit/525.18.1 (KHTML, like Gecko) Version/3.1.1 Mobile/5F136 Safari/525.20)

Why bother? Units is a free app and does the same stuff.

Sbrocket
Sep 22, 2008, 10:03 PM
Why bother? Units is a free app and does the same stuff.

There are three apps called Units - the free one and the $0.99 one both do conversions, yes, but neither will do conversions on the level of Equivalence because they (and no other app on the AppStore) mimics its landscape mode. I'm not quite sure about how many units they have, but Equivalence's unit library is extensive (260+ units in 31 types) and is constantly updated at the request of users thanks to its over-the-air update system. The third app, which currently costs the same at $1.99, does dimensional analysis and comes closer to Equivalence's purpose, but (at least I think) lacks in implementation and design.

Some of my reviews describe Equivalence's pluses well:
"The basic mode works fine and is probably comparable to other unit converters. The advanced mode of this application is head and shoulders above any similar product I've seen here. The power is that it combines a calculator and unit conversion (including the ability to recognize and simplify combinations of units based on dimension). So you don't have to write down the conversions, then switch to a calculator." - equivalence user (http://phobos.apple.com/WebObjects/MZStore.woa/wa/viewUsersUserReviews?personaId=2188943)

"A very good application with good use of iphone interface, easy to use and updated frequently. The missing units from previous reviews have been added. I spent two days one on one with the developer via email helping with an area I did not understand and was very pleased with results. Customer service of this caliber is hard to find these days." - rbach (http://phobos.apple.com/WebObjects/MZStore.woa/wa/viewUsersUserReviews?personaId=2153580)

"This application strikes a good balance between power, ease of use, and flexiblity. The developer is very responsive and helpful -- that alone is worth the price." - Traum1 (http://phobos.apple.com/WebObjects/MZStore.woa/wa/viewUsersUserReviews?personaId=1684610)

...and there's a lot more like that, especially in international stores.

"A response to a request for extra "time" units was met within hours. Now that's service" - UK

"today i bought equivalence 1.0.2 through the app store. initial thoughts are that this will be the converter to beat. very slick interface and future releases will add more features among currency conversion." - Netherlands

I'd be happy to answer any questions you have about it, but I will say (despite my biased nature, and at the risk of sounding haughty) that the other conversion apps don't come close to what Equivalence can do. :P

Spanky Deluxe
Sep 23, 2008, 03:49 AM
This is awesome, exactly the kind of conversion app I've been waiting for. Although, I do feel that it will make my brain a little bit stupider what with doing everything for me!! :D :D

For 1.19 it was a no brainer.

sammich
Sep 23, 2008, 04:11 AM
Dam that is one sweet app! I saw 'engineer' in the iPhone section, then I saw it was on sale, checked it was on sale and bought it with no hesitation. $2.49 in Australia, not even worth a coffee.

And at a great time too. Just when a big assignment is due.

Darth Cow
Sep 23, 2008, 07:20 AM
Can the calculator deal with CGS (Gaussian) units properly? Many unit converters can't handle the unit systems which aren't directly equivalent to SI. (In CGS, for instance, electric and magnetic fields have the same units, but in SI the units for the fields differ by a factor of velocity.) Handling CGS would be a killer feature for me (a physicist).

Sbrocket
Sep 23, 2008, 08:11 AM
Can the calculator deal with CGS (Gaussian) units properly? Many unit converters can't handle the unit systems which aren't directly equivalent to SI. (In CGS, for instance, electric and magnetic fields have the same units, but in SI the units for the fields differ by a factor of velocity.) Handling CGS would be a killer feature for me (a physicist).

It doesn't currently, no, but this is an interesting limitation that I'll have to look into. Could you fire an email my way (dev[at]apogee-dev[dot]com) so we can see about fixing this up for you?

DipDog3
Sep 23, 2008, 09:27 AM
There are three apps called Units - the free one and the $0.99 one both do conversions, yes, but neither will do conversions on the level of Equivalence because they (and no other app on the AppStore) mimics its landscape mode.

I was talking about the free "Units" app. It works for all of the conversions that I have ever needed and its FREE.

Sbrocket
Sep 23, 2008, 10:00 AM
I was talking about the free "Units" app. It works for all of the conversions that I have ever needed and its FREE.

Great - everyone gets to make their own choices. If it does what you need then that's all you need. I was simply making the point that it simply doesn't "do the same stuff." :p

MVApple
Sep 25, 2008, 10:03 PM
I was talking about the free "Units" app. It works for all of the conversions that I have ever needed and its FREE.

This is only good if you're a scientist or engineer. If you just need to do the very basic conversions, like feet to meters etc then go with the free one because it will do everything you want for free. The more advanced features are only useful to people who work in the sciences and thats why I appreciate an app like this being made. I bought one of the 0.99 ones and tried all of the free ones and none of them had all the conversions I wanted, although a to z pro lets you add your own and download more. I didn't want to bother with them and equivalence has all of the ones I wanted.

The free ones are miles behind in the quality of this app. I bought mine at $2.99, I didn't know it was $4.99 before. Even at $4.99 it would be worth it but unless I had tried it first I probably wouldn't have bought without knowing exactly how well it worked. I bought it without really reading the reviews. I was frustrated with the limited functionality if the free ones and the 1 dollar one I try and I just said "what the hell" and bought it.

*edit*

I have to say I apprecite the updates and continued support. Some developers I've noticed release new software with more functionality instead of updating there existing software.

Rybold
Sep 27, 2008, 02:34 PM
They are selling it for only $1.99 now!!! WoooHooo!
(it used to be $4.99) I just bought it for $1.99.

flameup
Oct 7, 2008, 08:27 AM
Rybold please give direct link to got that special if that is still valid.