Make: Projects

Adafruit Resistor Helper

Papercraft Resistor Calculator!

Steps

Step #1:

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  • Print out your Resistor Helper in color. It’s sized to fit on one 8.5″ x 11″ sheet.
  • The wheels are paired with small arrows. Cut around the holder and separate your wheel pairs from each other.

Step #2:

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  • Cut out and glue pairs of colored wheels back to back.
  • Liquid glue can make the paper curl a bit, so we recommend drying the wheels under a heavy book (or warm laptop) for about an hour. Or you can use a glue stick!

Step #3:

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Adafruit Resistor Helper

Line up your colored wheels by the letters and numbers – 4a is the first wheel on the 4-band side, for example. Keep track of your pieces because we’re about to cut out the ID numbers!

Step #4:

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  • Use a craft knife to carefully cut out the viewing windows in the holder.
  • Double check your windowed holder against your row of wheels so you still remember where they go.

Step #5:

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  • Now carefully cut out the inner circles on your wheels, placing each one back in line before cutting the next one.
  • Of course you can always refer back to this page if you forget which wheel is which!

Step #6:

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Cut small slits over the red dots on the holder (both sides = 8 cuts). This is where the paper fasteners will anchor each wheel.

Step #7:

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  • Shorten the tabs on four paper fasteners with a pair of clippers.
  • This is optional but we think it looks nicer!

Step #8:

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  • Use a ruler to gently score (but not cut!) the fold line on the holder.
  • The holder folds easily and neatly after scoring.

Step #9:

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  • Pierce a paper fastener through a tab on one side of the holder and through a wheel.
  • You can assemble the Resistor Helper with either side as the “front,” but we think you’ll use the 4-band side more often.

Step #10:

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  • Pierce through the opposite side of the holder and flare out the tabs on the fastener to secure.
  • Repeat with the other three wheels.

Step #11:

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Once you’ve verified you assembled the wheels in the right order, carefully glue together the corners/edges of the holder.

Step #12:

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That’s it! Use and enjoy!

Conclusion

This tutorial also appears on Adafruit and Instructables.

Becky Stern

Becky Stern

Becky Stern (sternlab.org is a DIY guru and director of wearable electronics at Adafruit. She publishes a new project video every week and hosts a live show on YouTube. Formerly Becky was Senior Video Producer for MAKE. Becky lives in Brooklyn, NY and belongs to art groups Free Art & Technology (“release early, often, and with rap music”) and Madagascar Institute (“fear is never boring”).