Make Your Own Odometer From Scraps

For those out there who would enjoy a quick and interesting weekend project, this odometer made by [PeckLauros] is for you. Featured on Instructables it is made from the simplest of materials including some cardboard, a calculator, wires, glue, hot glue, magnetic drive key, an old CD and a reader, and a rubber band.  The magnets, when attached to the CD work in a calculation to add 0.11m to the calculator when a magnet closes the circuit. [PeckLauros] points out that since it is a homebrewed device, it does have flaws such as adding 0.11m twice when the CD is rotated too slowly.  It is easily fixed by simply running faster.  The video is below the break.


11 thoughts on “Make Your Own Odometer From Scraps

  1. I once used a worn out pedometer for that. Cheap ones begin to skip steps after some time, however, they’re still good as a generic event counter if you provide reliable external contacts.

  2. How would one further this hack to solve the “reed bounce” problem when running slowly?

    One of the ideas I was toying with involves swapping the reed switch for a hall effect sensor, and feeding this to some hysteresis circuitry (an op-amp and some passives). I wonder if it’s possible to utilize a similar setup with the reed switch currently used.

  3. @reklipz

    I would go optical. IR gap photo-sensors are easily found inside old mechanical mice, floppy drives, scanners, printers, and lots of other plentiful (read: free) electronic items. You could even hack up one of those using a pair of LEDs–one emitting and one detecting. You’d probably also need a transistor to “push the button” on the calculator.

  4. Very old trick, I’ve seen that in a science magazine more than 22 years ago! But still a good hack.
    [reklipz] talks about the problems with the reed bounce when riding slowly and I remember having tried it at that time and it didn’t performed well with quick speeds too!
    I did use this trick with success though when I got graduate something like 10 years ago (sic!) using a big AT90S1200 with a software day-timer and one output connected on the ‘=’ key of the calculator, the other contact of the ‘=’ sign beeing the ground. By typing the numbers of days left before graduation minus one and letting the AVR grounding for a short time the ‘=’ sign once everyday I got this “graduation countdown” down working within a few hours! And with almost nothing to buy.

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.