Clocking in
So how does one convert a scale to a clock. It should be quite simple. Squeeze a motor in somewhere between the tray and the hand. I might even be able to use the “pushing down” of the tray to activate a button. That should be enough for a working clock.
Materials
If I wanted to make a “normal” clock. One with 12 hours. I could probably have used a ready made module. But where’s the fun in that? I tried to run one at half speed, but it wasn’t reliable enough. I don’t know if it was because of my hacking or the quality (or lack thereof) of the module, but the ones I tried ran either too fast or slow. I found a good video about how to use such a clock mechanism as a time reference, though. Do check it out, if you are using that route.
But I had this nagging thought, that daylight savings aren’t going anywhere, so why not automate the clock, so I don’t have to be aware of the disturbance in time?
As the brain behind that, I used an ESP8266. Somehow it seems that I always have one of those laying around. But any MCU with wifi capability could be used. Then I needed a motor. A servo, or otherwise one with an absolute indicator would have been nice. But I haven’t found any cheap ones that can do 360°. Then I remembered that there exists some cheap stepper motors.
Cheap as chips and actually with a lot of backlash. I’ll guess it is because of the gears in them. There might be a big difference from motor to motor, I haven’t tested. But lets see if it can still be used for a clock. Back at uni, we made a gripper attachment for a six-axis robot arm. That gripper used one of these motors to drive the jaws, and it was far more reliable and sturdy than what is fair for the price. I should still have some laying around in a box somewhere from that time. You always buy those 5-for-something deals too, right?
Found them, and “driver”/transistor boards too!
The board is a transistor array and LEDs. One for each wire to the motor. Handy for seeing what’s going on, or testing without connecting the motor.
Then it only needs to be shown where point 0 is, and the rest should be easy. But a helping hand from a human would be necessary. So that button function is coming into play. I have some heavy duty push buttons laying around too. They look a bit like comic sized version of regular round push buttons.
Trying so show the scale with the normal sized push button.
They are completely overkill in regards to wear, but its travel distance fits the travel distance of the tray quite nicely. With that, the materials should be sorted. At least the big parts. As you can see is it a simple build. At least hardware wise.
Now I just need the metaphorical (or maybe literal) hot glue and gaffe to cobble it all into a clock. The plans and diagrams will come in the next post.