I am in the preliminary stages of designing a radical keyboard.
Like the DataHand, the user's hand will not move, only the fingers will move a very small distance.
And like the DataHand, the keyboard layout will have 4 layers.
User input will be finger angles formed by knuckles.
I am considering two different ways to implement a physical keyboard that can sense the knuckle angles.
The next two sections describe the two physical keyboards:
Please tell me of potential problems I may have overlooked.
I would much rather know about problems now, than after building it.
Sensor GloveHere is an example of a glove with sensors:
Fabric bend sensors are located above each knuckle with bend accuracy and repeatability at +/- 1.5 degrees.
Haptic feedback is built into the glove. More details at:
https://www.bebopsensors.com/bebop-sensors-announces-forte-data-glove-arvr-applications-environments-gaming/https://www.youtube.com/watch?v=fM1UTwnIn6QA sensor on each knuckle would drive the keyboard firmware.
The finger joints are named:
- the metacarpophalangeal (MP) joint
- the interphalangeal (IP) joint
The ring finger in this diagram has the two joints labeled:
Thus there are 4 virtual keys per finger, which are pressed by:
- extending MP joint
- flexing MP joint
- extending IP joint
- flexing IP joint
I did not find a sensor glove in production.
I have requested a Data Glove and development kit from BeBop Sensors but have not heard back from them.
Do you know of a glove with accurate sensors on the MP and IP joints?
Finger CageIf a suitable sensor glove is not available, I could make a "finger cage".
A finger cage mounts buttons around the user's fingers.
A user inserts their fingers into the cage and the buttons sense the user's finger-joint movements indirectly.
The ring finger in the above diagram is annotated with 4 schematic buttons.
This is where the buttons would be mounted in the finger cage:
- 3 buttons around the fingertip similar to the DataHand finger well, but without the side buttons
- 1 button on top is labeled "knuckle button" in the diagram
A finger cage would have 4 such buttons on each finger.
Here is how the buttons would sense joint movement:
- Moving the MP joint presses the "knuckle button" or "tip button"
- Moving the IP joint presses the "nail button" or "pad button"
The prototype finger-cage buttons would be OMRON VX-01-1A2 limit switches, which have good tactile snap and a maximum operating force of only 0.25N {25 gf}.
Fingers would press directly on the red plunger (no keycaps):
The "knuckle button" is an untested idea as far as I know (please tell me if you know of such a thing).
The finger cage has some disadvantages compared to a glove. A user:
- can not simply lift fingers off the keyboard when not typing (e.g. pause to think), must hold fingers in the neutral position or pull out
- must be careful not to accidentally hit a button when moving fingers in and out of the cage
- needs to use mouse-move keys similar to DataHand (a glove would use hand gestures instead of a mouse)
Do you think a finger cage with knuckle buttons could be a practical keyboard?
Thank you.