Hmm interesting… I’ve also been busy working on this years robot, but I’ve gotten to the point where I can’t really test my robot any farther then it has gotten because I don’t have enough supplies at home. If I find the time, I’ll try it out! Thanks for sharing it!
I’m not interested in the challenge but I love the idea of a vex clock!
So far I found out that the hour hand needs to rotate 2 times a day, the minute hand needs to rotate 24 times a day. If the free speed of a 393 motor is 100 rpm’s, then thats 6000 rotations an hour, and 144000 per day.
When it comes to time you will have some issues because the motors don’t spin that fast over load.
I would recommend basing your number off of 50 rpm or something similar and then lower the power to get that speed.
Actually 60 rpm and then the second hand can be at a 1:60 gear ratio and so on.
At 100rpm for the hour hand it’s 72,000:1 (torque). To get to the ballpark of that, you need an 8-stage compound gear reduction:
7:1 x 7:1 x 7:1 x 7:1 x 7:1 x 3:1 x 1.4:1 = 70,589.4. From there, you need some tiny, minute adjustments. Tabor is right, it would probably be a lot easier to aid your efforts by setting the motor to a lower value.
Imagine using that on a drive! Using 4" wheels, your robot would move ~12.56 inches in 1 day.