This question requires a bit of background.

I am building a resistor colour-band machine out of an egg carton. The idea is - you are making a project. You are unsure of a precise resistance value you need, so you use a pot. Once you have the setting right, you take the pot, plug it into this machine and it gives you the 5-band colour code for the resistor you need.

The trouble is how to display the colours in the egg-carton cups. I can come up with a few ideas - all flawed:

  • RGB LEDs - but how do you display black and brown?
  • LCD - but where do you get a 2X2cm LCD?
  • Color wheel driven by servo/stepper - but how do you make it fit?

Can you think of any ideas that will work?


Why don't you draw the colors on a piece of cardboard or similar material and use the LEDs to indicate which color is needed. You only need to show the first 3 bands since they are for the resistor value, the others are for tolerance and reliability. Thus you would probably need a total of 30 leds, 10 for each of the first 3 bands. But the LEDs could be cheap red ones since they are only being used as indicators. If you want them to occupy a small area, place them in a circular pattern.

  • \$\begingroup\$ That's a good idea, but possibly not small enough. Nice concept though! \$\endgroup\$
    – felixphew
    Dec 14 '13 at 3:55
  • \$\begingroup\$ EDIT: I tried it, and it fits (just). Still seems a bit squashy, but a clever solution, so I ^1 'd it \$\endgroup\$
    – felixphew
    Dec 14 '13 at 4:18
  • \$\begingroup\$ I like your solution, but I would like some other ideas. Could you possibly ask anyone else to take a look at the question? \$\endgroup\$
    – felixphew
    Dec 29 '13 at 4:54

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.