3D Printing Improves Passive Pixel Water Gauge

Here at Hackaday, we feature all kinds of projects, and we love them all the same. But some projects are a little easier to love than others, especially those that get the job done in as simple a way as possible, with nothing extra to get in the way. This completely electronics-free water gauge is a great example of doing exactly as much as needs to get done, and not a bit more.

If this project looks a bit familiar, it’s because we featured [Johan]’s previous version of “Pixel Pole” a few years back. Then as now, the goal of the build is to provide a highly visible level gauge for a large water tank that’s part of an irrigation system. The basic idea was to provide a way of switching a pump on when the tank needed filling, and off when full. [Johan] accomplished this with a magnetic float inside the tank and reed switches at the proper levels outside the tank, and then placed a series of magnetic flip dots along the path of the float to provide a visual gauge of the water level. The whole thing was pretty clever and worked well enough.

But the old metal flip dots were getting corroded, so improvements were in order. The new flip dots are 3D printed, high-visibility green on one side and black on the other. The only metal parts are the neodymium magnet pressed into a slot in the disc and a sewing pin for the axle. The housing for each flip dot is also printed, with each module snapping to the next so you can create displays of arbitrary height. The video below shows printing, assembly, and the display in action.

[Johan]’s improvements are pretty significant, especially in assembly; spot-welding was a pretty cool method to use in the first version, but printing and snapping parts together scales a lot better. And this version seems like it’ll be much happier out in the elements too.

9 thoughts on “3D Printing Improves Passive Pixel Water Gauge

      1. There do also exist heaters/deicers for water tanks. Thermostatically controlled usually so they kick on/off depending on the temperature to keep the water from freezing. Can get them at any feed store around here (Minnesota) in at least a few sizes.

    1. Add salt to water and it won’t freeze much (or alcohol, depends on your need). If you need clean water anyway, it’s very likely it’s for gardening and you won’t use it when it freeze, so you can simply empty it.

  1. This is WAY overkill for no good reason that I can think of. I have a large water storage tank that captures rain runoff. At the bottom is an outlet with a T-fitting. One side of the T-fitting has the valve for releasing the water. The other side of the T-fitting goes to a clear tube that runs up the side of the tank. The water level is plainly visible. If I wanted to make it more obvious I could put a colored float in the tube.

    1. Ah, well, there I can help you. For starters the best kind of kill IS overkill, of course.
      In fact, a clear tube, with or without a floating indicator was considered, and even mentioned as an option in the predecessor to this project (https://hackaday.io/project/172388). The main problem is algae growth, which will taint the water, and eventually obscure, possibly even foul the tube. And this is very real – I even have to shield the water pipe running into the refrigerator (for the ice maker) from light, because of algae growth. Do not ask me how I know this.
      Because yes, to address the concern raised by others, I have not even considered the possibility of freezing. That is not going to happen here. We have many problems but freezing ain’t one of them.

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