Flipdots, Without The Electronics

We are used to flipdots, single mechanical pixels that are brightly colored on one side and black on the other, flipped over by a magnetic field. Driving the little electromagnets that make them work is a regular challenge in our community. [Johan] however has a new take on the flipdot, and it’s one we’ve never seen before. Instead of making a magnetic field to flip his dots he’s doing without the electronics entirely, and just using a magnet.

The project is a level indicator for a water tank, which contains a magnet floating in a plastic bottle. This has previously been used to trigger a reed switch that controls the refill pump. To those reed switches he adds a row of flipdots, but these aren’t the commercial dots you might once have seen adorning the front of your local bus. Instead, they’re custom dots made from washers, suspended in pivots by means of a spot weld and mounted in a frame inside a clear tube to keep dirt at bay. As you can see in the video below the break, when the magnet floats past inside the tank it flips them over one way, and on its return journey if flips them back the other. The result is a fully serviceable flipdot display, completely lacking the normal electronics, and we rather like it.

(It may be the first electronic-free flipdot we’ve shown you, but it’s not the first homemade one.)

14 thoughts on “Flipdots, Without The Electronics

  1. Potential minor upgrade… Green Yellow Orange Red paint to indicate “ideal” and not, levels. A florescent half-paint to show each 5″ or 10 gal or etc.

      1. I’ve already got rain Barrels (you need way more than you would think to water a garden) . Was thinking of something like this myself.. But so far not made it to the top of the to-do list, behind the sister project of a decent pumping system for all the barrels – probably using Hozelock type quick disconnects and a battery powered pump arragment – rather slow watering just with gravity pressure of maybe a whole meter and with more than one barrel on different sides of the house portable battery pump that can click onto the existing taps just makes sense.

        Though a fancy automatic irrigation system would be fun too…

  2. Completely ingenious, but before I read how it worked, I assumed it was water powered where each flipped element consists of a balance between a “weight” and a “float”. As the water rose I assumed the flipping was caused by the buoyancy of the floating side overcoming the dry gravity side. Anyway I guess I have a project now.

  3. I’ve worked in the oil and gas industry, and these are commercially available products that have been around for year. They’re usually called something like magnetic level indicators and are used when a clear glass level sight tube would get coated, dirty or oily and become unreadable.

    Only problem is they cost 10x or more what a sight tube costs, otherwise they’d be much more common.

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