“7 segment clock
This project was inspired by another similar project that I saw a few years back. I mostly rebuilt it completely and challenged myself to print it as small as possible on a standard 3d printer using a standard nozzle. The size was determined by the smallest screw hole that was possible. The clock consists of 4 modules which work in a pair to display the time. The mechanism is quite simple using a set of cams and followers. The stepper motor turns one module and the second one is driven by a carry over mechanism. The right side pair displays the minutes and the left side displays the hours.
The clock consists of 7 segments which are driven by seven cams. The cam push the followers which in turn lift the segments at the right moment to display the digit needed. The modules work in pairs. The entire clock is driven by a attiny 84 and two a4988 stepper drivers. The first module is driven by a 15mm geared stepper motor which turns it every 1 minute. After a full circle of the module the second module is driven by a carryover gear. The third module is again driven by a stepper motor which turns every one hour and then carry overs to the forth module at 10 and 12 o clock.”