Applied Fabrication · CMU 2014

StampMouse

An ergonomic mouse for low-precision clicking — the entire case is the button.

Abstract

Anyone can suffer from hand ailments that hinder one’s ability to perform grapple and touch-based tasks. Moreover, those conditions may complicate tasks requiring great precision.

StampMouse is a special ergonomic mouse in which the mouse click button is attached to the bottom of the cavity. Mouse movement functions normally. However, mouse click has been adapted for a low-precision context: a user need only exert a downward force anywhere on the mouse to trigger a click. This action resembles the operation of a stamp, in which the construct rests on a flat surface, but the primary action occurs when the device is pressed into the surface.

This work was the final project for the Applied Fabrication course.

2D diagram of the StampMouse concept showing the dome case, internal click mechanism, and optical sensor — StampMouse concept diagram. The case snaps onto a base housing the click mechanism — pressing anywhere on the dome triggers it.

The Problem

Commercial ergonomic mice reduce wrist strain — but they still require precise finger placement to click. For users with conditions like tendinitis, arthritis, or other injuries affecting fine motor control, even pressing a small button can be painful or unreliable.

StampMouse eliminates the precision requirement entirely: the entire top surface of the mouse is the button. Press anywhere downward — like using a stamp — to click. The action requires no finger precision, only a palmar downward motion.

Design

The interaction model was settled early: stamp-press anywhere on the case to click, normal optical sensor for movement. The form factor followed from that — a dome that fits naturally under the palm, with the click mechanism attached to the base rather than the top surface.

Whiteboard sketches showing different mouse form factor concepts and the stamp-click mechanism — Early design session. We worked out how the case, the internal circuit board, and the stamp mechanism would fit together before touching any modeling software.

3D Modeling & Printing

Dimensions were based on a disassembled optical mouse circuit board — we extracted the PCB and designed the housing around it.

123D Design 3D model of the StampMouse outer case showing dome form factor — Mouse case modeled in 123D Design. The case snaps down onto the base, triggering the click mechanism at the bottom.

All 3D printed components laid out alongside the extracted circuit board — Printed components and the salvaged circuit board before assembly.

Components were printed and assembled. Initial dimensions were off — some trimming and coordination between components was needed before parts fit properly. The final prototype also revealed the mouse was slightly oversized for smaller hands, and click sensitivity caused the cursor to drift on press — both candidates for a next iteration.

Role

Project manager and 3D modeler. Responsible for the outer case geometry in 123D Design, coordinating component sizing across the team, and user testing.