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60 second mechanical timer

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  • #16
    I just did a search for timer apps that can run on a computer. Assuming the teacher is using a large display or can set up for a large display there's lots of full screen timer apps out there. I'm sure a little checking would turn up an option which has both digital and analog displays.

    I'm thinking that instead of distracting them with actual numbers it might be better if they can just see a dial moving towards zero or sort of "pie chart" face where the "green" moves around and leave "red" behind until at the end of a minute it's all red and a tone announces the end. No cost at all... provided the teacher has a computer running that the kids can see.
    Chilliwack BC, Canada

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    • #17
      Hi,

      I asked about the sand timers and those don't really work well according to the teachers. Not enough "eye appeal". And digital timers are what is causing issues for the kids.

      Kids these days tell time by digital clocks and watches. And either can't tell time from an analog clock or they really struggle to do so. Nor does a digital clock do a good job at demonstrating just how long a minute is. The younger kids are often fascinated by my old school analog watch with seconds, minutes, and hour hands. And nothing is quite as good to teach "how long is a minute" than watching something move for a minute. And for these kids, something bright and colorful that moves and has an audible ding or buzz when done is the ticket. And the 60 second windup is simple and easy for the teachers to operate without much thought. Nor does it require an outlet to plug into to operate.

      I did score an old Ladybug 60 second timer from the Lunch Ladies at school. It's a bit sticky from hiding in a drawer for 30 years, but it has a nice satisfying ring at the end. Etsy is listing such timers for $30+! I suspect a bit of cleaning and lubrication and it should work just fine again. So I have a start.

      More sunlight and tea got me to remember Alibaba is a thing and has 60 second windup timers for $2.50 a pop. But shipping is a bugbear if you need it sooner than a month. But I think I'm going to order a couple anyway.

      I too was thinking about a quartz clock mechanism this afternoon. But I was unsure if the second hand pinion could handle a couple ounces of weight cantilevered out from it. A 3D printed arm and something like a colorful jet plane, sailboat, or puppy as the target to watch would work very easily. But Georgineer, if you think there is enough power there to handle it, I'm going to order one of those too. They are also very cheap. And easier to source to boot.

      I'm probably going to make the drive into the Big Evil City(tm) this weekend to checkout a store or two that was mentioned to me also. Might get lucky there.

      You guys have been a super help with this. It's often hard to find cheap effective tools to teach with.
      If you think you understand what is going on, you haven't been paying attention.

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      • #18
        Mechanical and kinda bullet proof.
        https://www.ebay.com/itm/Plastic-Two...cAAOSwqNRf~NJL

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        • #19
          For the engaging visual that you want I like @tom_d's idea of a marble chase. You could also use the kind that's a sloping board with nails or pegs, should be able to "calibrate" it by the angle of incline. The latter also has the advantage of putting plexi over it and sealing it so younger kids neither eat or make off with the balls.
          Last edited by gellfex; 04-01-2021, 05:48 PM.
          Location: Jersey City NJ USA

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          • #20
            Originally posted by dalee100 View Post
            ... But Georgineer, if you think there is enough power there to handle it, I'm going to order one of those too. They are also very cheap. And easier to source to boot.

            ...
            I'm only guessing, and I think the movement might struggle with an ounce or two, but who knows until you've tried! That's what makes engineering - and teaching - such fun.

            George B.

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            • #21
              I would think of the hourglass principal with a strong perspex outer tube to make it drop proof.

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              • #22
                How about a hydraulic gadget, something like those used on a bandsaw, but with a spring in place of the arm's weight. It could even be made in the shop, so there's machining content in this approach ;-)
                Location: Newtown, CT USA

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                • #23
                  Originally posted by GadgetBuilder View Post
                  How about a hydraulic gadget, something like those used on a bandsaw, but with a spring in place of the arm's weight. It could even be made in the shop, so there's machining content in this approach ;-)
                  Now there's a thought. You've reminded me of the pneumatic delay switches used in communal halls and stairwells:

                  https://www.screwfix.com/p/elkay-col...questid=544948

                  Robust, reliable, not too expensive, should be accurate enough for Dalee100's purposes, dull as ditchwater but he can add whatever eye-catching detail he wishes to be controlled by the switch. They typically reset with a firm 'thock!' when they time out, which gives audible feedback.

                  Are they available in Minnesota?

                  George B.

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                  • #24
                    Hi,

                    Not locally, but Amazon has one that would work. $14 is a bit more than I might want to invest at this point, but it is definitely a workable solution for another evolution to explore.

                    I have ordered a quartz clock mechanism and a 6VDC 15rpm motor from Amazon. The clock mechanism would be easy if it works. But I have been test printing a gear train for the gear motor. 1rpm ain't hard to hit with three gears and a ring gear to ride a turntable on. The size should be OK also. The accuracy of the gears is good enough for this application. A mini switch and maybe a buzzer from a trashed cell phone is possible.

                    Sadly, the lady bug timer is a bust. A couple of the nylon molded parts are broken inside. That explains the no workie after it wound down a bit.
                    If you think you understand what is going on, you haven't been paying attention.

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