How can I deal with resistors when I'm colorblind?

Question

Hey guys, Mike Wiltrout here. I believe many of you may know my father, John Wiltrout.

This really is not much of an introduction post, but it is my first on E-14. It is picture laden so I apologize for that ahead of time. I did, however, feel like it would be an interesting topic that some of you might be able to help me with, so here goes!

In my early childhood, I recall wanting to be a fireman. One day, my mother took me in to the clinic for a school physical. It was then that the doctor showed me a series of images with different color dots on them to determine if I was colorblind. Supposedly somewhere in the mix of dots on each image was supposed to be a number that I was to recite when I could make it out. Unfortunately for me I could make very few of them out. Below is an example of just such a chart and on that chart below I can really only make out the '12' in the upper right corner. It was then that the doctor began telling me about all of the careers that I would never be able to pursue. Included in that list was fireman. When I asked the doctor why I would not be able to be a fireman, he told me that firemen need to be able to see colors to be able to tell how hot a flame was. So I left the doctor's office that day a little bit sad and discouraged.

My father, being the troubleshooter that he is, set out to try and help me with my colorblind condition. He picked up color swatches in hopes that I might be able to "re-learn" the colors or at least be able to use the color swatches to compare against colors I wanted to know. Turns out it just doesn't work that way. The problem comes with being unable to differentiate. Red can look like orange, orange can look like yellow, yellow can look like green, green can look like blue, and so on. ORANGE means STOP and WHITE means GO! As a teen, I was interested in flying and wanted to get into the Air Force Academy, but pilots need to be able to see colors so they can tell if a plane is coming at them or flying away from them using colors on the wing and tail. I then considered the National Guard, where I was told that I could not be an engineer and that the ONLY military career paths that were open to me were about few different ones: a chaplain, a draftsman, or an infantryman. They wouldn't even let me be a cook because I cannot tell if meat is raw or cooked. Anyhow, you get the idea, being color blind can be a challenge. My wife finally made me get rid of my favorite blue office chair, because she could no longer stand the "hideous purple thing."

So, here is and has been my dilemma. How do I differentiate and identify the various color coded resistors?

My solutions so far consist of the following:

GET A BUDDY TO HELP ME - Preferably a buddy who is also not colorblind, but while a buddy might be able to help me sort a new collection of resistors into bins, he isn't going to be attached to my hip when I need a resistor identified on a project that I'm working on at 3AM.
MEASURE THE RESISTOR USING A MULTIMETER - This may work to identify a resistor outside of a circuit, but it also does not take into account any tolerances of the resistor, which I also cannot discern. I do not want to de-solder a leg on each resistor I need to measure on a PCB, either.
LABEL THE RESISTORS - This will work if I buy resistors that are in label pre-packaged bags and I am able to label them right away. I probably would look to label them according to either European or SMT standards in order to keep the labels as small as possible. This method takes a considerable amount if time, and I will probably only use it for prototyping.
PREMARKED RESISTORS - Some resistors like SMT resistors have their values printed on them. These I can figure out.
VISUAL COMPUTER AIDED ANALYSIS - Another idea that I had was to use either a camera, or a USB microscope to "scan" the resistor. The image could then be dropped into a computer program that would orient the resistor and scan the color bands displaying a value in Ohms and providing me the tolerance. I have no experience with any program that can automatic manipulation and color matching, so I'm stuck there.
FIX MYSELF? - The last idea would be to somehow fix myself with some type of contacts, glasses, or other medical method. (Again, not my field of expertise.)

The problem is not limited to resistors, either. I'm thinking a career in bomb disposal sounds pretty interesting, "Should I cut the RED wire or the BLUE wire?"

So lets hear some suggestions! GO!

valdaquendë · Answer

As a color-blind individual myself, I've had to struggle with this for quite a while. I read about ReScan, on this site and others but it is PC/Android only and requires a bit of putzing to install and get going. And although the app is quite responsive and can actually read the values to you via speaker, there were limitations, clarity and other issues I wasn't all that enthused about.

Recently, though, I found a $1.99 iOS app called ResistorVision by Jera Design. It uses the iPhone's camera to accurately check and report the resistor's values. For the most part, it works quickly and well, though it, like ReScan, has some limitations:

1) ResistorVision currently only works on 4-band beige axial resistors. Blue resistors and 5-band resistors are not currently supported, nor are surface-mount resistors.

2) It needs a colorless background (preferably white or gray) to be able to detect a resistor. A white sheet of paper or index card works fine but of course this can be a problem when trying to evaluate a resistor 'in situ'. I have resorted, once or twice, to cutting out a piece of a 3" x 5" index card and sliding it under a soldered-in resistor to provide the background the app needs. It wasn't much hassle - especially compared to unsoldering the resistor, measuring it with a MM and soldering it back in!

3) You need to position the iPhone so that the resistor almost fills a medium-sized rectangle in the center of the screen and there are, sometimes, focusing problems due to the camera focusing on the background instead of the resistor. Moving the iPhone or pointing it in another direction to cause it to refocus does the trick, though.

Overall, though, this is a very neat tool; I have had few problems with it and it is quite accurate. It's still being developed and seems to be improving as it goes. The devs ask that you email screenshots of situations where the app has problems and they use these shots to improve the program's zone and color perception. They are working on an Android version; emailing them and asking for one will undoubtedly speed up its development. Here are links to:

its very bare-bones website: ResistorVision

and its App Store page: https://itunes.apple.com/us/app/resistorvision/id839853035?mt=8

Cheers!

dougw · Answer

Maybe this app would help... Optical recognition of resistor codes | Labrigger from Nothing Labs (Rich Olson) Resistor Photo ID

4ringfan · Answer

jguss43 , Lighting and shading is an excellent point. In the dental industry, when they go to put a false tooth in your mouth, they put the patient under daylight lighting conditions and then they pick different teeth from a shade guide. They hold the individual shade up next to your existing teeth and move through the shade guide until they have one that most closely resembles the existing teeth. An advancement on that is that they have a device that emits a specific wavelength of light and reads the color that is reflected back to it. It then displays a letter / number combination that coincides with the correct tooth shade to select from the guide. mcb1 , I have not taken my digital microscope apart to see if the dial that I am moving is actually moving a lens, or if it is just a potentiometer that is spinning to adjust the zoom. I understand the differences between an optical and digital zoom, and the fact that a digitally zoomed image will decrease the dpi resolution of the image. Some of the image issues that you see in my picture revolve around the fact that I just took a picture of the screen with my camera instead of doing an actual screen capture. I do not think that there was a lot of pixelation at least at the resolution that I had zoomed to. My hopes with the microscope were to simply be able to capture a part in a tight location and isolate it from the surrounding parts, blow it up large enough so that I was not also fighting my eyesight as well as my color blindness. I can control the brightness of the microscope, it is just a ring of LEDs. I'm not sure what temperature of light that the LEDs are giving off, or if the colors reflected back are accurate or not. I can't do much about shadows without being able to get close and illuminate the entire part, and I can't fix the fact that some resistors will be dulled and old while others may be new and shiny. The color is what the color is. I just need to find a simple, fast, cost effective way to read them resistor's colors and Ohms. I'd like to use the device to read the colors of wires too. That'd be handy when I'm trying to figure out what wires are taps on a transformer, etc. Without color recognition, I see many explosive project failures in my future. Hehe.

gadget.iom · Answer

Hello 4ringfan Firstly welcome to the Element 14 community and congratulations on an entertaining first post! As your father will no doubt have advised you, we are a helpful bunch here, so feel free to snap a photo of a resistor and post it here anytime. The best long-term approach to your situation IMHO would be to explore the visual computer aided analysis you mentioned. Not only does it sound like a really cool idea, it would no doubt help others. Luckily, somebody has taken a very similar approach already, you can read more about it here: http://armageddon421.de/?p=279

How can I deal with resistors when I'm colorblind?

Top Replies