Combination Keyboard and Mouse
US patent #5,936,555

How it works

Brief overview

Figure 1 shows an overview of the prototype Combimouse.

Figure 1. Overview of system

The left hand unit is a stationary keyboard part.

The right hand unit is a mobile combination keyboard and mouse that can be gripped and moved around on a support surface as is done with a conventional mouse.

Normally the right hand unit is in keyboard mode. To change to mouse mode, the user clenches his/her hand and grips the right hand unit touching the area labelled Contact switch 1. A proximity circuit detects the finger contact, and the unit changes to mouse mode. During mouse mode the cursor is enabled so that movement of the right hand unit on the table/mousemat, causes the cursor to move. In addition, during mouse mode and depending on how the unit is gripped, the keys indicated become the mouse click buttons and the Scrolling keys.

Touching contact switch 2 enables the 2nd Fn keys. So if the user would like to press the Pg up, Pg Dn, Home, Endl keys, the palmrest is gripped, with the small finger touching contact switch 2 and the three middle fingers resting on the Home, Pg dn and End keys ready to press the required key.

(Contact switches 1 and 2 are actually implemented as the same switch, however in terms of functionality it is easier to think of them as two separate switches.)

As a mouse, the right hand unit has a similar mass and centre of gravity to the Microsoft Intellimouse. It has a similar grip to a conventional mouse.


Figure 2. Overview of prototype system

To accommodate left handed users; the left hand unit could also be designed as a mobile unit.

Detailed description of Right hand unit

Figure 3. Right hand unit


Mass 120 grams. Similar to Microsoft Intellimouse(with rolling ball) which is 115grams. The new Logitech Cordless MouseMan optical has a mass of 145 grams while the new Microsoft Wireless Intellimouse Explorer mouse has a mass of 152 grams. Production units will be lighter due to optimum design and state of the art components/materials (eg. Magnesium and light notebook keyboards).
Centre of resistance to horizontal motion relative to user's hand Similar to the Microsoft Intellimouse. (Determined by pushing the side of the unit with a pointed object and determining which position does not cause the unit to rotate).
Ease of movement The prototype requires 25% less force to move than the Microsoft Intellimouse.
Wrist rest. Used to rest the wrist during breaks between typing Same length as Microsoft Natural keyboard. Same slope as Microsoft Natural keyboards. Same effective resting area as Microsoft Natural keyboard.

Factors Contributing to High Mobility

The following factors have contributed to the high mobility of the right hand unit:

  • Low friction sliders.
  • As opposed to mouse rolling ball technology, optical movement detection technology is used, which doesn't contribute significantly to the mass of the unit. The rubber rolling ball in a conventional mouse has a mass of 30g.
  • Light notebook keyboard technology used.
  • Careful mass implementation. Conventional mice designs do not have a low-mass requirement and are inefficient in this respect.
  • Locating the user's hand well forward over the keyboard section during mouse modes, ensuring a favourable centre of gravity with respect to the user's hand.

Mouse modes

There are two ways of gripping the right hand unit during mouse mode. The first is referred to as normal mouse mode (see Figure 4), as this is the way that most people grip a mouse.

Figure 4: Normal Mode
In this mode only two fingers are on the mouse buttons (keys). The thumb grips the left side of the mouse. The small and ring fingers grip the right side of the mouse.

The second method of gripping the mouse is with three fingers are on the mouse buttons (keys). This is shown in Figure 5.

Figure 5: Three-finger Mode

Figure 6 shows the hand in the home position while typing.

Figure 6: Keyboard Mode

Numeric keypad

An integrated numeric keypad is implemented similarly to notebook computers. Due to the ability to move easily between keyboard and mouse modes, numeric entry in spreadsheets is very easy. This is shown in the demonstration video.

Adjustable palm grip

In order to accomodate different size hands it is possible to exchange the palm grip. In addition the palm grip can be slided to various positions to suit the user's hand size.

Communications from RHU to the LHU

For the prototype combination keyboard and mouse communications from the RHU to the LHU is via infra red.

The final design might use a RF link. This may increase the cost of the product and a commercial decision is required. The new Bluetooth technology may be the best solution.