Low actuation force asetniop input device

Keys4all’s first prototype is a keyboard designed for people with little strength and freedom of movement in their hands. This input device will probably also be very suitable for people suffering from repetitive strain injury or RSI.

Description

The keyboard will have 10 keys, 1 for every finger, two for the left thumb. Under the right thumb will be a trackball to replace the mouse. If thumb mobility is an issue, mouse functionality can be handled by the other keys. The hand will be in a natural position, keys being placed according to the form of the hand, not the other way around. The key actuation force will be very low and keys will be activated by bending the fingers instead of pushing.

Asetniop

Asetniop is a keyboard layout, just like qwerty and the lesser known azerty. With asetniop typing there is no need to change the position of your fingers, you form letters by pressing multiple keys at once. A sort of chord typing if you will.

Hardware

This input device will be using a Teensy 3.0 micro controller. Teensy is connected to the computer via a usb cable. Because the driver software will be on the micro controller this input device will work with any software or operating system. As key switches we will use the VX5-1A2 microswitches which have an actuation force as low as 0.25 Newton. They also have high quality tactile feedback. However these microswitches can’t be used in situations where they can be exposed to high force or impact, this would damage them.

The case of the prototype will be made of polymorph so adaptions can easily be made. In the future we hope to make use of a 3D printer for the cases.

Software

We will be using our own custom drivers that process the (simultaneous) key presses within the micro controller and send the correct characters to the operating system, because of this the keyboard will be operating system independent and suitable for use with all software. Typing will also be considerably faster and more accurate compared to asetniop drivers seated in the operating system.

The code is relatively easy to adapt. An alpha version can be obtained at github.

Cost

  • Microswitches (Omron VX5-1A2): €2.24 * 10 = €22.40
  • Teensy 3.0 with pins: €17.22
  • Breadboard: €3.12
  • Polymorph: 500g = €15
  • Wire: €14
  • Material for fastening (screws, etc.): €10
  • Faston terminals (6.3x8mm, insulated): €0.20 x 30 = €6.00
  • Trackball: €10

Total: € 97.74 (excluding taxes and shipping cost)

We hope to bring this price down to €80.00 by bulk stock acquisition. This is only possible with the help of donations as we don’t have the funds to buy large quantities of supplies at this time.

The price will also be lowered when we can make use of microswitches with a higher actuation force.

Alternatives

The only commercially available alternative that comes close with the layout and actuation force is the datahand. This does however require use of your legs (mode switching). You will also have to move your fingers more because the datahand uses 5 keys per finger. As for the price, it’s an astounding $995 (excluding shipping). There used to be a cheaper non professional version, but it’s no longer listed at their website.

Update: the datahand has been discontinued. It’s now only available through second hand purchase, this has driven the price up considerably.

Plans

As an extra we would like to implement the steno functionality of asetniop. This would have to be a separate ‘premium’ software version though, as it is intellectual property of asetniop and we want to keep our code as free as possible.

Status

The driver software and design of the prototype are practically finished. What we’re waiting for at this time is funding for material. If you’d like to contribute, there’s a donate button to the right of this article. The goal amount is higher than that of the cost of a single keyboard because building a prototype involves making mistakes.

Do it yourself

If you want to build your own keyboard we have some help for you. The source code for the driver is available at the github link under software. The building plans and a manual will be published here once the prototype is done. We will also be offering DIY kits by that time.

Commercial exploitation

The software and blueprints will be released with a permissive open source license, though we haven’t decided on which one exactly. Almost anything will be allowed as long as it stays open source. So if you produce a keyboard based on our design you have to provide the source code to your customers. We also require you to mention Keys4all or the Humanity4all foundation and Pointesa LLC (asetniop).

We encourage commercial exploitation our our design as we want to reach as many people as possible with our input devices. Feel free to contact us if you have plans in that direction, we might be able to offer you a spot on our website.