Resistor Color Code Clock




Introduction: Resistor Color Code Clock

About: Always looking for things to improve, repair, improvise, or modify. Studied mechanical engineering and physics at Stanford with a focus on robotics and international development. Some favorite topics are el...

Call me a huge nerd, but I recently decided it was necessary to memorize the color codes used to designate the values of different resistors.  I've also recently become interested in making (relatively) large scale representations of electronic components, either in a semi-functional or purely artistic way.

A wall clock seemed a perfect fit to learn colors - it's something you might look at a number of times per day, it has roughly the right number of digits/colors, and it's generally useful anyway.  So I set out designing and after cycling through a couple other designs, I settled on using acrylic parts - beige for the resistor cores, gray for the inner and outer "wires" - glued together with electrical tape wrapped around.  It's certainly possible to make it into one big piece of acrylic and painting the cores, but this seemed like more of a challenge and a bit more fun.  The clock is 10" in diameter, a good medium sized clock.

Now there's a great new way to learn the color codes and eliminate the need for a google search every time I'm working with resistors!

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Step 1: Supplies

  1. 11 x 11 x 1/8" ivory acrylic (TAP Plastics)
  2. 11 x 11 x 1/8" dark gray acrylic (TAP Plastics)
  3. Clock movement (Amazon)
  4. Rainbow electric tape (Amazon) - need black, brown, red, orange, yellow, green, blue, violet, gray, & white
  5. 1 AA battery (wherever)
  1. Laser cutter
  2. Acrylic glue (TAP Plastics)
  3. Hypo applicator (TAP Plastics)

Step 2: Cut Acrylic

Download the .dwg files here, throw the acrylic in the cutter, and get to it!

I had some trouble with file formats and compatibility, so here's what I ended up doing.  I created the design in Inventor Fusion, which conveniently does not export into any files that CorelDraw 11 was able (or willing) to import.  So I ended up exporting from Inventor Fusion as .stp, importing that into Inventor, and exporting as a .dwg.  Problem is, CorelDraw 11 also refuses to read those.  So then I imported the .dwg's that I just exported back into Inventor and exported them as .pdf's.  CorelDraw 11 was able to read those, thankfully.  However, the .dwg's were exported as white, so I had to correctly scale and change the color to black (and thickness to hairline).

Hopefully it'll all work smoothly for you!

The "ResistorCenters" file contains all 12 "resistor" cores, the square outline I thought I'd use as a frame around the clock movement but ended up breaking to use as the reinforcing struts, and an outer ring that could be used on the clock but was used more for scaling the file in CorelDraw than anything else.

The "Wires" file contains the outer rim, three hubs with slightly different length arms (to make sure the interfaces with the cores are flush), and a few small rings you can use on the clock face-movement interface if you want.

Once you've finished cutting, carefully remove the masking from all the parts to reveal the beauty that lies below.

Step 3: Apply Tape to "resistor" Centers

I considered a couple different ways of assigning colors to each clock number.  At first I assumed I'd do three bands of colored tape with one for the tolerance, just like real resistors.  Then I thought maybe I could simplify it and make it look more elegant by sticking to the bare minimum - one strip of tape that signifies the only important digit for 1-9 and two for 10-12.  I decided to go with the latter.

Grab the ivory acrylic resistor cores and all the rolls of electrical tape.  For 1-9, apply a single strip of tape once around the part, making sure that one of the sides doesn't have any evidence of the ends of the tape strip.  For 10-12, cut the tape down the middle to make pairs of half-width colors - this way the clock will look more uniform overall.  I placed them so that on 10-12 there's a space between the two strips - especially important for 11 (Brown-Brown) to distinguish it from 1.  Also for 10-12, I chose to orient the colors so you read the number going radially outward, so Brown is on the inside, with Black/Brown/Red on the outside.

The number-color correlation is below:
  1. Brown
  2. Red
  3. Orange
  4. Yellow
  5. Green
  6. Blue
  7. Violet
  8. Gray
  9. White
  10. Brown-Black
  11. Brown-Brown
  12. Brown-Red

Step 4: Glue Parts Together

For this step, grab your acrylic cement, the hypo applicator, the just-taped resistor cores, the outer rim, and the inner hub(s).

First, use a funnel to pour the acrylic cement into the hypo applicator or, as noahw pointed out to me, you can simply suck the cement straight into the hypo applicator.  For a good tutorial on this step and gluing acrylic overall, check out TAP's tutorial here.

In the following steps, it doesn't matter exactly which colors/numbers you use, but the order (i.e. the successive resistors and their relation to one another) worked for me.  I just didn't want to go clockwise only to find that things didn't fit nicely as I got farther around; instead, I did opposite sides in succession.  There are many permutations of the order I chose - do what you think! Be patient with this step - acrylic sets fairly fast but not instantaneously.  Also keep in mind that the cement essentially melts any acrylic it touches, so be careful with have scrap pieces underneath.  It's good to keep the parts you're connecting off of any surface at the interface - this eliminates any chance that your parts will stick to something accidentally.  Finally, you may want to glue your cores upside down - then, if you have a couple stray drops, you haven't ruined the front face of your clock.  If you do it upside-down, be careful with where you put 3 and 9 (and all others, for that matter) - if it's upside-down, it'll be mirrored!
  1. Lay down the outer rim and put the inner hub somewhere near the center.
  2. Place the 12 resistor (brown side toward the center) between outer and inner gray pieces.  Press the resistor and the outer rim together, and apply cement to the interface.  Hold for a couple minutes.
  3. Press the center hub against the other end of the resistor and apply cement to the interface. Hold for a couple minutes.
  4. Repeat steps 2 & 3 in the following order: 6 (blue), 3 (orange), 9 (white), 1 (brown), 7 (violet), 5 (green), 11 (brown-brown), 8 (gray), 2 (red), 10 (brown-black), 4 (yellow)
Note: make sure on the two digit numbers that you stay consistent - either make brown facing the center on all of them or the opposite way.

Once you've finished with the gluing above, you may want to add supporting struts to add to the strength of the interfaces.  I did this for a little extra toughness and definitely for peace of mind.  These are shown in the last few photos. Note: make sure you glue these on the back!

Step 5: Attach Clock Movement

The clock movement comes in 5 pieces plus the hands:
  1. Main body/movement
  2. Hanger
  3. Rubber gasket
  4. Brass washer
  5. Mounting nut
  6. Hour hand
  7. Minute hand
  8. Second hand+open nut OR cap nut
As shown in the photographs, the list above is not only the parts's also more or less the assembly progression.  Just put the assembly you just glued together between the rubber gasket and the brass washer, and the rest is pretty self-explanatory!

Step 6: Hang It Up!

Over time, I have no doubt this clock will help anyone to memorize the colors in resistor codes.  Hang it up above your workbench, get rid of all those clocks with real numbers, and let the colors permeate your mind!

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    16 Discussions


    4 years ago

    OHM my god! (see what I did there) That is awesome!


    4 years ago

    I tip my hat to you! this is the ultimate elctronics geek clock. This is simply a MUST DO project.


    5 years ago on Introduction

    This is an cool idea! Thin I must make one for my small workshop !!

    hey im wanting to make this for my brother for a Christmas gift but i don't have a laser cutter is there any way you can make a file you could open in word or something like that please get back to me asap


    Reply 5 years ago on Introduction

    There are free dwg file viewers available, but they may not print out to paper. I suggest purchasing( your going to have to buy clockworks anyway) a new white faced clock at Walmart or some dollar store, and borrow color markers from some kid if you don't have any


    7 years ago on Introduction

    Join the resistance! "OOOHHHHMMMMM!"


    7 years ago on Introduction

    Great idea! I made mine with "cheaper materials".

    SAM_4384 copy.JPG

    7 years ago on Introduction

    Brilliant. I've been using the colour code for over 50 years but it never ocurred to me to do something like this. Great idea!


    7 years ago

    Just love it!


    7 years ago

    awesome! I love this ! great idea.