A Clock From An Electricity Meter

Electric utilities across the world have been transitioning their meters from the induction analog style with a distinctive spinning disc to digital “smart” meters which aren’t as aesthetically pleasing but do have a lot of benefits for utilities and customers alike. For one, meter readers don’t need to visit each meter every month because they are all networked together and can download usage data remotely. For another, it means a lot of analog meters are now available for projects such as this clock from [Monta].

The analog meters worked by passing any electricity used through a small induction motor which spun at a rate proportional to the amount of energy passing through it. This small motor spun a set of dials via gearing in order to keep track of the energy usage in the home or business. To run the clock, [Monta] connected a stepper motor with a custom transmission to those dials for the clock face because it wasn’t possible to spin the induction motor fast enough to drive the dials. An Arduino controls that stepper motor, but can’t simply drive the system in a linear fashion because it needs to skip a large portion of the “minutes” dials every hour. A similar problem arises for the “hours” dials, but a little bit of extra code solves this problem as well.

Once the actual clock is finished, [Monta] put some finishing touches on it such as backlighting in the glass cover and a second motor to spin the induction motor wheel to make the meter look like it’s running. It’s a well-polished build that makes excellent use of some antique hardware, much like one of his other builds we’ve seen which draws its power from a Stirling engine.

4 thoughts on “A Clock From An Electricity Meter

  1. I was hoping to see a Duncan meter made in Lafayette In. They were used in many states. One of those as a clock would be a hit here. The forward and backwards nature of the gearing and display makes it hard to read.

    1. The tens dial is almost all the way from 5 to 6, and the units dial is almost all the way round to zero. I reckon that’s meant to be interpreted as “59” (almost 60), but you’re right, it’s a little counter-intuitive.

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.