Device Details

Overview

The Finger Lift Switch is an assistive switch that is activated by lifting a resting finger upwards. The switch activation distance is approximately 5 mm and the required operating force is 2 to 5 grams, depending on balance screw adjustment.

Usage

Connect the cable to an assistive device with a 3.5 mm input jack. The user’s lifting fingertip should be placed under the finger lift pad, resting on a lower surface or splint.

When the user raises their lifting finger, the finger lift lever will rotate and activate the switch. The switch will de-activate when the user lowers their lifting finger back to the resting surface.

Cost

The cost of components for a single switch is approximately $11 CAD. However, obtaining the minimum quantities  for a single build will bring the materials costs to $66 CAD.

 

Build Instructions

The Finger Lift Switch consists of 3D printed parts and electronic components. The Assembly Guide is available at the GitHub repository.

Skills Required

  • 3D Printing
  • Soldering
  • Assembling screws

Time Required

3D Printing Time: 1hr 30m

Assembly Time: 30m

Tools

  • Soldering Iron (fine tip)
  • 60/40 rosin core electrical solder
  • Medium size Phillips screwdriver (type #1)
  • Side cutters
  • Wire strippers
  • Super glue (gel type is best)
  • Hot melt glue gun (low temp type)
  • Permanent felt marker (fine tip)
  • Needle nose pliers
  • Sturdy metal tweezers
  • Multimeter (with continuity reading capability)

 

Components

  • 1X Ball Bearing: Type MR85ZZ (8 mm OD 5 mm ID)
  • 2X 5 mm x 1 mm Magnets (Neodymium)
  • 1X Reed Switch (Glass) Contact Normally Open (N/O) Magnetic Induction Switch (2 mm × 14 mm)
  • 2X M3 x 8 mm Stainless Steel screws (Base & Base Cap screws)
  • 1X M3 x 10 mm Stainless Steel screw (Counterweight screw)
  • 1X M3 x 12 mm Stainless Steel screw (Bearing Screw)
  • 1X M3 x 16 mm Stainless Steel screw (Balance screw)
  • 5X M3 Stainless Steel Nut
  • 1X 1/4-20 (Imperial size) Nut
  • 1X 5-foot mono audio cable with 3.5 mm male phono plug

 

3D Printing

  • 1X Finger Lift Lever (3D)
  • 1X Balance Screw Holder (3D)
  • 1X Counterweight Nut Holder (3D)
  • 1X Bearing Base (3D)
  • 1X Bearing Base Cap (3D)
  • 1X Reed Switch Plate (3D)

Design

This design was created using OpenSCAD.

Attribution

Designed by Makers Making Change (Derrick Andrews) in conjunction with Sunnyhill