Mechlets: Counter Module

The Counter Module is part of Mechlets, a modular system of mechanical machines that connect together and transfer motion from one module to the next.   This module turns rotary motion into a two-digit mechanical count. Each complete revolution of the input advances—or reverses—the counter by one, depending on the direction of rotation. When paired with the Hand Crank Driver Module, one full turn of the crank equals one count, making it easy to see the relationship between input rotation and the mechanical counting mechanism. The counter displays values from 00 to 99. Continue forward past 99 and it rolls back to 00. Reverse the input direction and the count runs backward. Part of the Mechlets System Unlike most Mechlets, the Counter Module is designed as an end-of-chain module. It accepts mechanical input from another Mechlet, but it does not have an output gear for driving another module.   Connect it to a Mechlets driver—or place it at the end of a connected series—and the incoming rotation is used to operate the counter. If this is your first Mechlet, visit the original Mechlets collection to find: Hand Crank Driver Module Thumb Slider and Thumb Scroller drivers Additional mechanical modules Splitters and connecting modules for building larger arrangements How the Counter Works The blue dial on the front acts as a visible indicator of the incoming rotation. As the input turns, the dial rotates with the mechanism. Each time the blue dial completes one full revolution, the displayed count changes by one: forward rotation → +1 reverse rotation → −1 The first digit counts the ones, while an internal carry mechanism advances the tens digit after every ten counts. This creates the familiar sequence: 00 → 01 → 02 → … → 09 → 10 → … → 99 → 00 Reverse the input and the same mechanism operates in the opposite direction. Watch the Mechanism Work Although the number wheels are enclosed by the display cover, the internal counter mechanism can be viewed from the bottom side of the module.   This lets you see the gears, carry mechanism and indexing components interacting as the counter advances. It provides a good example of how continuous rotary input can be converted into discrete mechanical steps and stored as a visible number. Paired with the Hand Crank Driver, it becomes particularly easy to explore: 1 crank revolution = 1 count That makes the Counter Module useful not only as a display, but also as a hands-on demonstration of mechanical counting, indexing and carry-over. Fully 3D Printed The Counter Module is built entirely around printed mechanical parts and snap-fit assembly: Two-digit 00–99 mechanical counter Forward and reverse counting Visible blue rotation indicator Mechanical ones-to-tens carry mechanism Internal gears visible from the underside Snap-fit retaining clip No screws No glue No bearings, motors or electronics The included assembly guide walks through the input gear, bearing frame, carry mechanism, number wheels, cam, display cover and final testing.   Note: After assembly, rotate the mechanism through several complete counting cycles. This helps smooth out minor print roughness and lets the moving parts seat and operate more freely.