Scroll solutions for the Combimouse

A scroll wheel has been added to the prototype. Previously we considered putting it to the left of the comma key as shown in the sketch below. However we have put it on the right side of the comma key. As of October 2014 it appears to work well but hasn’t been fully tested. To save battery life it is only active during mouse mode. This isn’t ideal as one has to be gripping the unit to activate mouse mode and often during scrolling the unit is lightly gripped. This will be fixed in the future.

The following paragraphs talk about the various scroll solutions considerations prior to June 2103. I have left them in the blog as a reminder.

There is no ideal scrolling solution for the right hand Combimouse part.

On the earlier prototype a Scroll wheel was located on the left part but that is not ideal and will be removed.

Currently the thinking is to implement both the Gesture Scrolling and Click Scrolling methods as described in the first two solutions below. The third solution is likely to also be present.

Gesture scrolling by moving finger along surface of the Comma key

This is the same that is done on the Apple Magic Mouse and some Microsoft mice.

By moving your finger along the surface scrolling will happen.

This hasn’t been implemented yet on the Combimouse, but it is expected to work and is practical to implement even though it is fairly complicated. I did say it is practical to implement - that needs to be confirmed.

There is a disadvantage of this system as it is very sensitive and doesn’t give as much control as a scroll wheel.

The other disadvantage is that it is only available for Mouse Grip 1 and not Mouse Grip 2

Mouse grip 1


Mouse grip 2

Click scrolling

This has been implemented and works well. The disadvantage is that like the Gesture Scrolling method it doesn’t provide fine control.

One advantage is that works for both mouse grip modes.

During mouse mode, if the P or Semi-Colon is pressed and released, the unit goes into scrolling mode. If you move the mouse up or down from this zero position scrolling goes up or down. The further you move from the zero position the faster the scrolling. If you keep the mouse at a position away from the zero position scrolling accelerates quickly. This makes it easy to jump to the top and bottom of documents.

To get out of the scrolling mode, any key is pressed or you got out of mouse mode by stop touching the touch sensor on the right side of the unit.

Alternate Click Scrolling

This method was prototyped but is not practical.

If you were to press a designated key during mouse mode, scrolling would occur by moving the mouse. The problem is you need to keep moving the mouse for scrolling to continue. By the time you are finished scrolling the mouse has moved very far.

Pointing stick

The pointing stick as shown below has been considered. It wouldn’t move the cursor as it normal does - rather it would produce scrolling in the direction it  pushed. I discarded this option - I must confess that I can’t remember why. I think it was due the high power consumption.

One advantage would be that the same pointing stick  could be used with both mouse grip modes. It also doesn’t add significant mass far from the centre of gravity


Thumb Wheel Scrolling

This method has been suggested and is being considered, although it would seem that it probably is not a good solution.

The big advantage is that it is accurate and has good control.

Two scroll wheels located on the mouse grip as shown in the diagram below would be needed. Two scroll wheels would be required - one for each mouse grip mode.

One problem is that there there would not be enough space for the thumb between the Space key and the side of the side when using the top scroll wheel. In addition the height below the keyboard to house the scroll wheels is not sufficient. There is only 7mm available.

Another problem is that the thumb may not be suitable for continuous scrolling and may cause RSI - this is just a gut feeling and may not actually occur.


8 thoughts on “Scroll solutions for the Combimouse

  1. John

    Why put the scroll in the mouse part first of all? The right hand gets too much strain with a usual mouse - moving, clicking scrolling. I myself find a scroll wheel on the left side much easier. For CAD applications you could a second scroll wheel for zooming.

    Actually I prefer clicking with the left hand as well. What I have done for this purpose is to program the keys of a USB Numpad to perform mouse clicks and position it on the left side of the keyboard. Distributing strain more equally to both hands works great for me.

    1. admin Post author

      If you look back at old Combimouse prototypes you will see that the scroll wheel was on the left side. I then decided that it was wrong and the Combimouse had to reproduce as far as possible a standard keyboard and mouse. I found it annoying that I didn’t have a scroll function on the right Combi. It’s interesting that you think that a scroll wheel on the left Combi would be better - I have to think about it but to be honest right now I am not convinced.

      1. John

        It must be tested. But my own experience and logic tell me - the right hand is occupied with too many repetitive physical operations and over-strain ensues.

        1. John

          One more thing - when placing a scroll on the left side, it needs to have a different shape, as the left hand is not in holding a mouse and fingers remain in a different position. A beautiful (= ergonomic ) solution is this model: . This is the most convenient keyboard I have ever used and I am currently typing on it. Additional keys on the left side present incomparable usability.

          And you can always have two scrolls. When people get tired from the right scroll, they would naturally change to the left one.

          1. admin Post author

            I had a look at that keyboard you linked to. How do you find scolling with the left hand? Do you think it would be a good idea to only have scrolling on the left combi? That would make it a lot easier for me - implementing scrolling on the right combi is difficult.

            1. John

              With this large scroll on the horizontal axis I find it very convenient because I can scroll with two finders at a time - which does not strain one particular finger and what’s more important, you do not need to curl your fingers as much in order to scroll. I can also scroll by using my thumbnail while gripping the side of the keyboard with the other fingers.

              As for having an easy to implement scroll function on the right part - you can try to do it simply by keys. I am not speaking about the arrow up and down keys. They are not positioned ergonomically for scrolling. You need to add two additional scroll keys, at a proper position, probably with some distance between them. And in order to make the movement smoother, you’d need special software. Mkey ( have done scroll emulation beautifully.

        2. admin Post author

          Possibly the right hand could be over burdened, but I need to think whether it is an issue. Scrolling is a different action to others. To be honest I am not convinced. I think we are too accustomed to having the scroll function on the mouse and I am trying to keep things as much as possible the same.
          However I haven’t dismissed your suggestion. I will keep on thinking about it.

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