resistr app - A beautiful, easy to use, resistor color code calculator

[nadavt]

Hi There!

As an avid maker and EE student, I often find myself trying to decipher some color code on some obscure resistor or maybe needing to know the colors of a certain resistor value.

Trying to use those resistor tables or awful online calculators just isn't fun or efficient. Also, as a person that admire product and graphic design, I was often thinking that there must be another way - not the 'engineering' way, of laying out ALL the information for you to take, but a more subtle approach that would help beginners and won't overwhelm them unlike other apps on the market.

Thats why i've came up with the idea of 'resistr'. It took me almost two months (and all of my free time) to design, build and test the app - trying to keep it simple but not underpowered.

The result is a gorgeous app with a simple and fun user interface, that hopefully every EE student or amateur will be hooked instantly. 

I'm currently in the final stages of testing the app and uploading to the iPhone AppStore. I've began developing the Android version as well, which I hope will be available in the next couple of months.

[EDIT]
resistr is now available! visit our site at http://resistr.co or search the AppStore to download.

[cs.dk]

An app i find really helpful is Electro Droid. It does resistor color codes + all sort of other calculations. Really handy.
https://play.google.com/store/apps/details?id=it.android.demi.elettronica

[robimarko]

Yeah I use electrodroid daily,but this app has really beautiful design

[bwat]

Sorry but I just had to say the following as it seems you're quite serious about this and not viewing it as a little project. I hope you can accept it in the spirit of constructive criticism in which it is offered.

Trying to use those resistor tables or awful online calculators just isn't fun or efficient.

To be honest, I think you're trying to find a problem for your solution.

As someone who is not colourblind and has fairly decent vision, it seems like you've taken a problem that can be solved very quickly with a piece of card with a chart printed on it (that was actually part of the packaging of the box of resistors you bought so you cut it out for future reference) and built a slower solution that requires a microprocessor and manual input. You've added new steps to an old process giving the same result.

Consider this quote:

Prolonged contact with the computer turns mathematicians into clerks and vice versa.

If your software isn't pushing the "clerks" into the realms of "higher thought", then  maybe you're not using your programming skills to build the most interesting things. You've only got so many keystrokes in you so use them wisely.

[cellularmitosis]

Looking forward to it!

[josem]

Looks good thanks.

Another good resistor app is ResistorVision which I use to decipher resistor values by simply pointing my iPhone camera at them: http://resistorvision.com

[tszaboo]

And does it have 4 or 5 color resistor calculators? Or EIA SMD calculator? Or tolerance? Where is the windows phone version? Why is this better than a paper hanged on the wall of the hobby corner?

[nadavt]

Thanks everyone for your comments!

I can certainly relate to the comments about the usage of resistor tables and cards and I've used them myself many time through the years.
While not trying to say that my solution is the most efficient one of all, I do think that there could be a solution which is more enticing and less intimidating for use with people that are not used to reading or using more technical engineering tools.
By making an this app, I think that students and hobbyist would find it useful and more accessible to use than plain resistor tables.

Regarding 4 and 5 stripes resistors - After the first version will be approved, I will try to incorporate more features like that and have them available in a future software update. Just need to design and think how to do it easily as to not miss the main purpose of the app.

Hope I made my vision clear
Thanks again all!

[AndyC_772]

Is decoding resistor values really that intimidating compared to whatever piece of design actually requires someone to work out a resistor value?

I'm all for keeping things nice and simple, but the hardest part of decoding resistors is seeing what the colours are on a tiny part, and reliably telling the difference between them. And there really is no shame in testing a resistor with a meter, however unfashionable some people (who, in my experience, are *never* actually design engineers themselves) may think it is.

If you actually want to use the colour codes, then learn the sequence. Black, brown, red, orange, yellow, green, blue, violet, grey, white. It's really not that hard.

I'm afraid I think your two months' worth of free time would have been much better spent learning, say, how to use an FPGA or an ARM based microcontroller if you can't already.

[onlooker]

Yes, something like http://resistorvision.com is more interesting for the developer and the user.

It would be even better if someone can come up with an app that can do full fledged  pattern recognition for all resistors on a board from a picture and place a little text box near each of them in a smart way.

[nadavt]

I'm afraid I think your two months' worth of free time would have been much better spent learning, say, how to use an FPGA or an ARM based microcontroller if you can't already.

The way I see it is that this app might help welcome new students and hobbyist into the electronics field, using a design language that they already understand and feel comfortable with it.
Although this app only tries to solve one hassle amidst the vast range of problems that the average student has to deal with, if it does that well enough - I certainly won't consider my time to be wasted on learning new skills such as iOS and Android development.

Personally, I think that software development skills are not less important for an engineer these days than learning a new ARM micro...

Thanks.

[c4757p]

People don't just memorize this?

[amyk]

Two months to make a GUI with some pretty buttons... I hope that includes the time you spent to learn app development. Not bad if it's one of your first apps but I agree with the others here that its usefulness is limited. There are tons of these calculators out there already.

Besides the fact that the resistor colours are one of the first things one should memorise when beginning electronics, the increasing popularity of SMD also makes this less relevant...

[aroby]

Looks good thanks.

Another good resistor app is ResistorVision which I use to decipher resistor values by simply pointing my iPhone camera at them: http://resistorvision.com

A shame that's not on Android.

[Stonent]

People don't just memorize this?

Well some of us have other professions. 

[tautech]

Black, Brown, Red, Orange, Yellow, Green, Blue, Purple, Grey, White.
Didn't even look at a chart, and for me it's a hobby.
Really how hard is it? 

[SeanB]

Try remembering that along with the telephone cable colouring system. It works well, even if the colour orders are different, and they call the grey coloured wires slate. But you do find a lot of white and red wires there though.

https://en.wikipedia.org/wiki/25-pair_color_code

[rob77]

actually it's pretty easy to learn "reading" the resistor values directly from color code. i don't even think about the colors i see - i "read" the value directly. it's like learning an extremely simple language

[VK5RC]

Black Bull Ran Over Your Garden Blue Pansies Gone West,  works for me,  esp past yellow,  I never seem to forget 0—4., to me the biggest problem is who came out with the idea of a blue background,  cream was a lot easier.

[tautech]

the biggest problem is who came out with the idea of a blue background,  cream was a lot easier.

What about the backgrounds of: bright green, red, dark brown, purple and fawn, not to mention the 3 shades of green, 3 of cream, and at least 3 of blue.

And that assortment is in my resistor trays.
Whats more I've seen yellow instead of gold and gold instead of yellow. 

Now how will one write the software for imagery to sort that mess out and identify the values correctly? 

Learn and remember the colors and you have them for life.

[eneuro]

There are good tricks for memory improvements 

[bwat]

The way I see it is that this app might help welcome new students and hobbyist into the electronics field, using a design language that they already understand and feel comfortable with it.

1) "design language" -  garbage! Read Mitchell's "The Logic of Architecture" http://www.amazon.com/The-Logic-Architecture-Computation-Cognition/dp/0262631164 for a way to express design in a formal language - not some airy fairy nonsense but first order predicate logic. That book is the best intro to logic I've ever read.

2) You're making things difficult for beginners. Apps like yours help beginners become good at being beginners. It doesn't help them make to move on towards competence and expertise.

Personally, I think that software development skills are not less important for an engineer these days than learning a new ARM micro...
Thanks.

I qualified my comments with the observation that this was not a little project because I think little projects are very important. I've written many many lines of code which were written as a proof of concept or just because I thought it would be nice to be using my own programming language compiler/cryptographic algorithm/operating system/etc. Mind you I would never lower myself to the level of writing an app - I'm a serious programmer don't you know!

[Stonent]

Green-white, green, orange-white, blue, blue-white, orange, brown-white, brown.

That's currently holding the place in my memory where resistor codes would have been.

[rob77]

Green-white, green, orange-white, blue, blue-white, orange, brown-white, brown.

That's currently holding the place in my memory where resistor codes would have been.

actually it's better to remember the pairs 1,2 - 3,6 - 4,5 - 7,8 and then associate the colors orange, green, blue, brown - and you know the wiring for both standards - just remember orange and green pairs swaps for the other one
and this way you remember the cross cable wiring as well - just swap the pairs on one end   furthermore if you know which pairs are used for what technology - you know the wiring for all of those
fast etherne 1st + 2nd pair
gig ethernet - all of them
ISDN 2nd & 3rd pair
POTS - 3rd pair

[Stonent]

Green-white, green, orange-white, blue, blue-white, orange, brown-white, brown.

That's currently holding the place in my memory where resistor codes would have been.

actually it's better to remember the pairs 1,2 - 3,6 - 4,5 - 7,8 and then associate the colors orange, green, blue, brown - and you know the wiring for both standards - just remember orange and green pairs swaps for the other one
and this way you remember the cross cable wiring as well - just swap the pairs on one end   furthermore if you know which pairs are used for what technology - you know the wiring for all of those
fast etherne 1st + 2nd pair
gig ethernet - all of them
ISDN 2nd & 3rd pair
POTS - 3rd pair

Yeah and some previous guy where I worked decided since 100BaseTX only needed 4 wires, he split pairs and in some places have 2 ports on one cable.  All of that's going to have to go since we're getting a new VOIP phone system that wants Gig and POE.