BEZICRON

Description

Inspired from the hair rubber band of my daughter I created a mechanical clock which stretches a flexible elastic borrowed from a flexible pen to make the digits. The arms are moved by cams which stretches the elastic band to make the digits. Each digit approximately measures 50mmx 55 mm. The entire clock is about 300 x 140 x 150mm

Details

The clock consists of 4 modules of digits paired in two units. Each pair is powered by a 20mm geared stepper motor. Each pair has one module driven by the stepper motor and the second module is moved by a carryover mechanism. Both the units are controlled by a control board in the base containing a atmega8 running in the arduino ecosystem.

The single module

The entire assembly of 4 modules

The base

It contains the control board which consists of a Atmega 8 and a pair of a4988 stepper drivers

the complete drawing

Components

1 × Atmega 8 microcontroller

2 × A4988 Power Management ICs / Motion, Motor and Servo Control

3 × A3144 hall sensor

2 × push buttons

Project Logs

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testing a dual module with carryover
ekaggrat singh kalsi • 4 hours ago • 0 comments

next I assemble a dual module to test the carryover mechanism. I worked smoothly as the 20mm geared stepper is a overkill for this purpose. The units motor homes to zero using the hall sensor and then runs clockwise to change the digits. After every one turn it carryovers to the tens module using a carryover gear mechanism.
testing a single module
ekaggrat singh kalsi • 4 hours ago • 0 comments

I built a single module to test the concept. The module was driven by a geared 15mm stepper motor which was controlled by a cnc shield. I quickly realized that the torque need to turn the cams and followers was much more than I anticipated. The 15mm motor ran very hot and overworked. So in the next iteration I used 20mm geared stepper motors