Wearable electronics are becoming a more common part of everyday life, but it’s not often that we see wearables that move or change shape on their own. Incoporating electric motors on the body can present challenges even for experienced designers and makers. It can be a complex challenge, and the factors for a good design aren’t well understood.
We decided to develop some simple, versatile parts that attach some of most common types of small motors and actuators to the body. The idea was to make a set of building blocks that can be used to try out ideas, construct more complicated kinetic systems, or just play around!
The Kinetic Wearables Toolkit is a set of 3D printable adaptors for small servomotors, stepper motors and solenoids that can produce several kinds of motion in multiple axes using 3D printed parts with multiple attachment options.
This is our initial release of this toolkit. There is more we can do with cable management, batteries and microcontroller/driver integration, as we get more experience using motors on the body.
You can find detailed models on our github repository. Please let us know how these designs work for you. We’re looking forward to making more moving wearables and adding parts as we go!
Wearable electronics require particular design considerations different from other electronics, such as containment, washability, proxemics, and social acceptability. We wanted to build upon these to suggest design factors for wearable motors and kinetic systems (moving parts attached to motors). We looked at assistive and rehabilitative devices, where safety and weight are major considerations, along with durability, reliability, and portability. The process of developing the Kinetic Wearables Toolkit revealed additional design factors for wearable motors and kinetic systems:
- Push/pull/bump protection of motor/mechanism
- Adjustability of range and orientation of motion
- Stability of attachment to body
- Attachment/integration with electronics and power
- Protection from and dissipation of heat generated bymotors
- Pinching/tangling protection for wearer
- Managing chafing and irritation resulting from repetitive motion
Our initial research focused on the first three of these.
Choice of Actuators
This toolkit uses small motors commonly used in hobbyist and DIY electronics projects that can be driven by Arduino-compatible microcontrollers, and small batteries. Motors generally produce either rotary or linear motion. The two small servo motors used here are the same size, but the continuous servo can be programmed to rotate at a particular speed in either direction, while the 180 degree servo can be programmed to rotate to a particular angle in a limited arc. Stepper motors usually require driver circuity, however this small stepper motor can be driven directly from the I/O pins of an Arduino microcontroller, and can be made to rotate to a particular angle or continuously in either direction. The solenoid is a very simple actuator that quickly moves a plunger a short distance in and out of a coil. Linear motion can also be produced by attaching either servomotor to a linear motion adaptor shown below.
It is possible to mount motors to rigid portions of clothing and accessories (belt buckles, jewellery, hat brims, etc), or to make special-purpose clothing that integrates structural support for motors and associated electronics. However, this toolkit is intended to be versatile, for use with just about any clothing. These adaptors use lapel pins, velcro straps and a type of tab-in-slot mechanism found in suspender clips and garter clips
The following sections introduce the components of the Kinetic Wearables Toolkit.
Servo Flex Tilt Base
This base is 3D printed in a flexible material (Ninjaflex TPU)