28 replies to this topic

[jwjames83]

I've searched high and low online, and just can't find any resistors with bright colors. I'm probably not searching the right places, and I understand that it's been this way for nearly 100 years, but aren't there some brightly colored resistors for visually impaired? I have a heck of a time trying to distinguish green, blue and violet. Not to mention yellow is practically not even there. Can anyone point me in the right direction in getting easier to read colored resistors? Or am I wishing for something that just doesn't even exist?

[Mario Vernari]

OH! I've a friend who has visual problems, and when he was building circuits, often mistook the resistors, just because the colors. I don't know if there's any solution for the discrete resistors. The colors are pretty the same worldwide. I know the SMD resistors (surface mount) have a numbered code printed on...I don't guess that's a good solution, though. The only tip I could do is using the multimeter, to test the value. Consider to take care to store them in several boxes, and don't mix them... Sorry! Cheers

[OppaErich]

Nice project idea - Resistor colour code reader. Far off my scope though. I would use a meter and measure their resistance.

[jwjames83]

I figured that'd be the case. I'm just surprised there isn't more of a demand for a brighter green, or a brighter blue, or darker yellow, or a more violet "violet". I'm thinking the colors that are displayed on your computer when you look at what green is (0,255,0). That alone would help a lot (at least for me).

[JerseyTechGuy]

In my 20 years I've never come across bright colored resistors. There are certain resistors that may have a number on them instead of color bands. I think some Russian made ones are like this. There are also film resistors (thick and thin) that have numbers stamped on them, but these are special use (microwave applications, etc). I would just invest in a good meter. If you have a lot of resistors to measure you can perhaps make a simple rig to easily lay or snap them into when working on projects. Meter is the only solution that will guarantee a correct read because I've even seen certain manufacturers use a shade of red that is either close to orange or close to brown in some instances.

[Mario Vernari]

I really don't know how many are the people having visual inabilities, or whatever they call. BTW, this post makes me thinking a lot about this problem...and how to solve it. The multimeter way is obvious, but if I were -even an hobbist- testing almost all the resistors...surely I'll throw everything out of the window... My "open" question is: suppose having a normal webcam connected to the PC, then a imaging-processing software capable to "rotate" the colors. I mean acquiring a certain HSL (Hue-Sat-Luma), then change it upon the user's preferences. The result is displayed directly on the PC. Well, surely *NOT* a panacea, but it's pretty simple to do, taking advantage of tons of free libs anywhere. Also a webcam is just an affordable device. I must admit that this question is slightly off-topic, but...anyone would like to comment? Cheers

[Chris Walker]

If you have reasonably good eyesight, several of the thick film through-hole resistors have values printed on them (instead of stripes). I use them on breadboard projects quite frequently, partially because they match the characteristics of resistors we use on our assembled products. Chris

[Terry Massey]

I have to admit I would have probably thought of the web cam idea myself but as I was reading this post it became clear to me there might be a better solution. We have these color sensing sensors. Why not a small pen type device that could be easily ran across the side of a resistor with a readout of the colors and the value. not sure how acurate the sensors are but I wouldn't think it would be too hard to do. some bright white led source and the color sensor.
Just a thought

I really don't know how many are the people having visual inabilities, or whatever they call.
BTW, this post makes me thinking a lot about this problem...and how to solve it. The multimeter way is obvious, but if I were -even an hobbist- testing almost all the resistors...surely I'll throw everything out of the window...

My "open" question is: suppose having a normal webcam connected to the PC, then a imaging-processing software capable to "rotate" the colors. I mean acquiring a certain HSL (Hue-Sat-Luma), then change it upon the user's preferences. The result is displayed directly on the PC.
Well, surely *NOT* a panacea, but it's pretty simple to do, taking advantage of tons of free libs anywhere. Also a webcam is just an affordable device.

I must admit that this question is slightly off-topic, but...anyone would like to comment?
Cheers

[liqdfire]

Color impairment effects 1 in 12 men, so it is pretty common. I have the same issue, and it has been my largest hurdle with learning electronics. The multimeter idea is out, I can tell you from experience, especially when you are talking lower values on 5 and 10% resisters. I have to buy mine in small packs that have the values printed on the packaging, and if I forget which value one is, in the trash it goes. I thought about writing a smart phone app that would take a picture of a resistor and tell you the value, but I just never did.

[OppaErich]

Hard to tell how much people are color blind. Only males are affected. It's rare here in Germany, brits seem to have a higher rate.

I was thinking camera when I wrote 'nice project idea' and that would be too much for me. But it is possible, someone at the Parallax forums built a Guitar Hero playing device. This thing is analyzing the video signal.

I didn't know that there are color sensors, that may be not too hard.

Edit:

I thought about writing a smart phone app that would take a picture of a resistor and tell you the value, but I just never did.

Ooooh, a buddy of mine does IPhone apps for a living, I've posted him about it.

[jwjames83]

I thought about writing a smart phone app that would take a picture of a resistor and tell you the value, but I just never did.

This was my initial thought, an app (iPhone, Android, whatever) that could read the colors and spit back the value. But I think even then the camera of these phones might have an issue discerning between two very close colors.

I've attached a photo - both taken with my iPhone. On one side of the photo, the flash was on, on the other, the flash was not. It wasn't until I took this picture and displayed it on my computer, that I saw it was Green-Blue-Orange-Gold. One the far right is what I'd love for it to look like.

I guess that an old fashioned magnifying glass and a flashlight will have to do. I'm seriously amazed a company out there doesn't have neon colored resistors - even just as a novelty.

Attached Files

•  resistors.jpg   428.72KB   60 downloads

[liqdfire]

This was my initial thought, an app (iPhone, Android, whatever) that could read the colors and spit back the value. But I think even then the camera of these phones might have an issue discerning between two very close colors.

I've attached a photo - both taken with my iPhone. On one side of the photo, the flash was on, on the other, the flash was not. It wasn't until I took this picture and displayed it on my computer, that I saw it was Green-Blue-Orange-Gold. One the far right is what I'd love for it to look like.

I guess that an old fashioned magnifying glass and a flashlight will have to do. I'm seriously amazed a company out there doesn't have neon colored resistors - even just as a novelty.

The ones on the left are definitely spaced out enough and bright enough to detect the colors.

[jwjames83]

The ones on the left are definitely spaced out enough and bright enough to detect the colors.

If a reliable app could be written, I'd be willing to pay $4-5 bucks for it.

[Mario Vernari]

jwjames83, let me know: taking the photo above, you'll able to read the left resistors (i.e. colors), but the right ones not? It's just to mean what is your colors perception.

[jwjames83]

Well - don't forget, this picture shows the resistors at maybe 100x its original size. With the picture, I can distinguish the colors very easily on the left (with flash), not so easily in the middle (without flash), and on the right is what I wish it would look like without any flash (they could stand to be even a bit more neon colored.) I'm not color blind, my vision is just not so great.

[Nevyn]

I'm not color blind, my vision is just not so great.

I have the same problem - age is starting to get the better of me

[CW2]

Nice project idea - Resistor colour code reader. Far off my scope though.

It is also possible to use a microcontroller-based circuit to measure the resistance - Netduino is sure an overkill and given .NET MF limitations, certain parts can be challenging (precision, range etc.), but I guess it could be done. There are several approaches, like measuring voltage drop on the resistor (with constant current source) or capacitor dis/charging time in RC circuit. Imagine two blade contacts you put a resistor onto, an LCD display...

[Valkyrie-MT]

I thought about writing a smart phone app that would take a picture of a resistor and tell you the value, but I just never did.

What about this?

http://wmpoweruser.c...e-this-weekend/

-Valkyrie-MT

[jwjames83]

Now THIS is what I'm talking about: http://www.ebay.com/...9#ht_500wt_1288 Look at some of those pictures and see how bright the blue is! How bright the orange is! And what a difference between blue and green. Now *that's* what I'm looking for. A side question though - are vintage resistors safe to buy? What kind of shelf life do they have (if unused)?

[Paul Newton]

I have some old resistors similar to those. The colours are quite good on the dark background. I would not think twice about using them in a low voltage circuit - such as with a Netduino. But, there might be some risk using them in high votage circuits. Beware of vintage capacitors as some types were made with paper that can degrade with damp. Paul