Your Puzzle’s Done When The Electronics Says So

We can race against the clock when assembling jigsaw puzzles online but what about competing against each other in the real world? [HomeMadeGarbage] came up with the simplest of solutions with his jigsaw puzzle timer that stops only when the puzzle’s completely assembled.

Copper strip on back of puzzle
Copper strip on back of puzzle

His simple solution was to attach copper foil tape to the back of the pieces, with overlap. He did this in a serpentine pattern to ensure that all pieces had a strip of the tape. The puzzle he used comes with a special container to assemble it in. At two corners of that container, he put two more pieces of copper foil, to which he soldered wires. Those two act as a switch. Only when the puzzle is completed will those two pieces be connected through the serpentine strip on the back of the puzzle.

Next, he needed a timer. The two wires from the puzzle container go to an Arduino UNO which uses an ILI9325 touch panel TFT display for both the start, stop, and reset buttons, and to show the time elapsed. Press the touch screen when it says START and begin assembling the puzzle. When the last piece is inserted, the serpentine strip of copper tape completes the circuit and only then does the Arduino program stop the timer. As you can see from the video below, the result makes doing the puzzle lots of fun.

Naturally, it takes some work to apply the copper tape and you wouldn’t likely do this for puzzles with a thousand pieces but most online puzzles don’t have many pieces either. It’s the fun of the race that matters, and with people taking turns, you want it to be quick anyway.

If you have a printed photo that you want to turn into a puzzle with suitably sized pieces, then you can use this online program that produces an SVG file to tell your laser cutter how to cut out the puzzle. Or maybe you’d prefer to make a robot to make the puzzle for you? In that case, you can start with [thomasgruwez]’s pick and place jigsaw puzzle aid.

長女ちゃんも奮闘!

A post shared by Home Made Garbage (@homemadegarbage) on

10 thoughts on “Your Puzzle’s Done When The Electronics Says So

  1. Makes it sooooooooo much harder to do with that added copper tape!!!!!!LOLOLOLOLOLOLOLOLOLOL

    OK trolling aside:
    Nice concept and idea in a well constructed… IMHO: Prototype.
    An upgrade would be using glass or conductive transparent polymer pieces under the puzzle pieces with conductive strips of metal-oxides/polymers like seen on LCD screens in strong light (The metal-oxide on glass for LCDs)

    That way, the competitor wouldn’t cheat by feeling or looking at the underbelly of the pieces as they’ll hide their secrets seemingly almost invisible to normal viewing and task-use.

    1. Oh, forgot: Using metal springs on all 4 corners to aid contact between the metal-oxide on two sides and the other two to thwart guessing attempts.

      However, that’ll be something [HomeMadeGarbage] can look to making in the future, resources permitting.

  2. I think comments on this forum should be positive and promote “thinking outside the box”, but this project is riddled with failure. One small loose, damaged, or “bad” connection will cause it to not work when the puzzle is complete. In my opinion, it’s just the wrong application for the wrong project. An Arduino is overkill when a modified Chess timer could be used.

        1. Common Core Math:
          – Standards aren’t high enough in some regions, therefore we’ll force lower standards on the rest of the country.
          – Order of Operations is optional, Infix notation can be substituted at any time to give a different but equally correct answer
          – Draw your rectangles with the larger dimension horizontal or else you fail

          I like the idea of a unified set of educational standards. Those standards shouldn’t be the lowest common denominator (Wikipedia for any Common Core students who see this: https://en.wikipedia.org/wiki/Lowest_common_denominator ), especially if superior regions will be forced DOWN to that standard.

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