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Confidential Prototype Work

We have shown a lot of detail on the Combimouse website. There is a possibility that someone is copying the Combimouse and so we would like to keep as much design detail confidential.

I have spent 2013 and 2014 updating the prototype so that the Combimouse is ready for production. From about August 2014 I started sharing on Twitter what I am doing from day to day. I would very much like to talk about everything but we feel that we need to keep as much as possible confidential for now.

So you will notice that I don’t discuss details and show photos of the underside of the right Combimouse. I also don’t show details of the Printed Circuit board.

For the left Combimouse this isn’t an issue as it is a basic keyboard. I should start working on it by October 2014 and I will post numerous details and photos.

This is the reason why I am vague on many of my Tweets.


Working on Combimouse Prototype (2013-2014). Status on 18 Aug 2014.

Ari Zagnoev – 18 August 2014

I have been posting a brief monthly status update on the Combimouse website. In this blog I will go into more detail.

My preference is for you to post comments on the Combimouse website instead of commenting here.

Let me know what you think of this blog and if you would like me to discuss any other topics or if you have any other feedback.

Things should start speeding up and we will then be more active on social media. At the moment we only have 32 likes on Facebook. I reckon we deserve more than that. As someone has pointed out we haven’t been very active so maybe we don’t deserve more. Soon  things will pick up and we will become more active, but we need to get the ball rolling. My preference is to post less with a focus on quality and interesting news.

I have been working on the latest Combimouse prototype since 2013. The aim is to make a prototype that is ready for mass production that can be made at a competitive selling price. Also the aim is to use latest technology. Once the bulk of the development is complete we will then approach investors to help us get into manufacturing.

One of the objectives of my current work is to improve the battery life of the Right Combi. Previously it had a battery life of about one week. I estimate that the current prototype has a battery life of at least 3 months. This is with only one AAA battery which just goes to show how technology has improved. When I look at the low current consumption of the various ICs I am astounded. This is without any attempt at optimisation. Later when there is time I will optimise power consumption and I expect to get at least another month or two battery life, but at this stage it is a low priority task.

I have made good progress and I now feel that with the possible exception of the keyboard modules the end is in sight. The keyboard modules consist of the keys, key mechanism and flexible membrane circuit. During this development I haven’t made many any announcements and haven’t being active on social media. Development is such a risky endeavour with many setbacks and frustrations. If I were to tweet about them it would be appear chaotic. Often things don’t work as expected and do strange things – I would say to myself that this thing has it’s own law of physics – but of course once I find the cause of the problem it all makes sense.

I have been working on a limited budget and have done everything myself. This is not optimum and this has resulted in development has taken much longer than I would have hoped for.

I have redesigned the right Combi plastics. It is now a lot more structurally stable and is manufacturable. I am an electronic engineer with no experience in plastics design however I have researched the subject and have received advice from the company in China that will potentially manufacture the Combimouse – more on this later. I still need to run the design through mold flow analysis software to determine if the design is suitable. I will do this once we have funds and can commit and liaise with the manufacturer. In addition when we receive funds an experienced Industrial Designer will design the plastics.

To keep costs down the plastics must be designed bearing in mind Injection Molding requirements (if you are interested here is an article). The Combimouse design is a three way compromise between strength, weight and cost to manufacture. Tooling for injection moulding is very expensive and will be more than US$100K for the Combimouse. However the design will probably will be optimal for injection moulding and there will be no unnecessary incremental tooling costs. For example, for now I don’t envisage any undercuts.

Software development requires that the human readable code must be converted to digital information that can be run on electronic devices. A compiler/linker is the software that does this conversion. The compiler/linker for the Nordic processor is expensive so I haven’t purchased it and have had to make a number of compromises. This won’t affect the final product.

I have updated all the electronics. There was always a risk that something wouldn’t be suitable  or that there would be some incompatibility and interference between sub-systems. As of 18 August 2014 I would say that this risk has been greatly reduced. I now have most things working.

As of 18 August 2014 I have the following:

Dongle – I have had a dongle PCB manufactured that is exactly the same as the reference design from Nordic. It did work but as discussed below I had some problems programming it. I am currently using the development dongle on the development kit.

Left Combi – I have a working circuit board. I have an old plastic housing which should be okay. I haven’t yet integrated the keyboard. I made a mistake in specifying the membrane and so the tail is incorrect and is too short. I might use it but it will mean that I can’t use the real housing. I might have to order a new membrane but I am waiting to see if there are any other problems on the left membrane and possibly problems on the right Combi membrane – I order them together.

Right Combi – I have an old plastic housing (as discussed below I have to make a new one). I have a populated circuit board that likely has no problems (this is a big achievement). I have adapted the reference mouse/keyboard software solution from Nordic and for now everything seems to be okay. The keyboard brake still needs to be tested and I still need to add the keyboard. The  mouse works well.

At the moment the proximity sensor on the right Combi takes about 17 seconds to calibrate when it is first powered up – ie. when a new battery is inserted. I spent some time trying to resolve this and I will probably need to contact the supplier to ask for assistance. It is a nuisance during development because I have to wait. It isn’t really an issue for production Combimouse because it only happens when one changes the battery.

The proximity sensor on the Right Combi at the moment has a relatively slow response time. I haven’t measured it but it probably is something like 100 to 200ms from when the right Combi is gripped to when the mouse starts working. I need to look into that and hopefully I can improve it. I do have some ideas.

There are also at least three other risks

1. I haven’t yet implemented the keyboards. I have found a keyboard manufacturer. This has been difficult. Their keyboard design has some limitations which I need to assess. They have sent me sample keyboards and they have made custom membranes to my specification. I have typed on the sample keyboard and my initial feeling is that they are not very comfortable – they require a high activation force and have an uncomfortably hard end to the key press travel. Soon I will work on the keyboard. The keyboard design from the supplier is suitable for the Combimouse because it can be integrated to give a lightweight solution. I will be using some of their components and will need to work out how to integrate it – there is some uncertainty here but I’m sure I will find a good solution.

2. I have the electronics and software mostly under control. I am now working on the right plastic housing. I will then add the keyboard. I have simulated key presses by shorting out tracks. I expect the the keyboard will interface well with the electronics but there is always a risk.
3. I am using the solution from Nordic. I have adapted their reference solution which is a separate mouse and keyboard. I have obviously had to adapt their solution and combine the keyboard and mouse solution for the Right Combi. For now I have got the basics working and it seems to be okay. Hopefully there will be no problems when I am typing at full speed with both the Left and Right Combis working simultaneously which is not what the reference solution is designed to do. At this stage I don’t know but my gut feeling is that it will be okay.

Besides the above there is still a lot of cleaning up and optimisations to be made. The Combimouse will support user firmware upgrades which reduces the software development risk considerably.

Fortunately I only had to have one revision of the PCBs manufactured by a PCB company. Having PCBs made is relatively expensive. I have had to make numerous hand modifications to these first revision PCBs, but for the most part they aren’t too messy and the current board is very usable. I am very happy that I have not had to have many revisions manufactured. Previously I used to etch PCBs myself but with the move to the new technologies this wasn’t possible because the Nordic radio/microprocessor IC is located on the board. This is a small pitched component and it wouldn’t have been possible to etch the board. In addition – previously I would drill holes and solder through wires for vias. These vias could obviously not be under components and this made the PCB design impossible to be etched myself as the latest version is very compact.

There were a number of times when I could no longer program the microprocessor with the latest draft software. This was a problem for both the dongle and the Right Combi.

For the Right Combi that meant discarding the board and repopulating a new one. I am not sure why I had these problems and this was very frustrating. I have discarded a number of boards after first attempting to remove the IC. I have changed a number of things in my development setup and my latest board appears to be reliable with respect to software changes – although I shouldn’t speak too soon.

This was a real problem with programming the dongle when I could no longer reprogram the microprocessor. Probably the cause of the problem was that I thought I could save some money and I did not buy their adapter. I made my own. Eventually after some time Nordic sent me a free adapter and they also sent me a development dongle which doesn’t require an adapter. They sent me these items because we couldn’t work out what was going wrong. I haven’t use their adapter yet but rather their development Dongle – so some unknown still here but I am thinking that it should be okay.

As I have a lmited budge I am making the plastic housings by hand. I am using ABS plastic sheeting and welding with Methylene Chloride. If I had funding I would probably use CNC machining. That is suitable for one offs. Stereolithography is better if more than one are required. 3D printing is not suitable as I discuss in this blog. On 18 August 2014 – my Right Combi house has distorted because I had not stiffened it up when I made it last year. So I am going to hand make another one – that should only take a few days.

I have moved to Melbourne. Previously I had identified a suitable Chinese manufacturer. The design company is in Perth. I have had over ten years experience with this company. However now that I have moved to Melbourne we may need to identify another company – but then again the Perth company is very good and we may stick with them.

The burden of finances has been an issue for me. We do have a number of shareholders but I am the main shareholder and I have to finance everything. This type of development would normally require a significant investment but I have found ways to do it on a limited budget – the downside of course is that it takes longer.

There was also so much to be done but now that I can see the end in sight I feel a lot more confident. I would say that from now on the issues for completing the prototype, are mostly mechanical which are a lot easier to identify and address. Whereas previously, when the microprocessor/radio and the proximity sensor did strange things it was very difficult as they are difficult to fault find.


Here are some interesting computer input devices that I am aware of. If you know of others please let me know.


KeyMouse Kickstarter

KeyMouse Grip

I think that there are a number of significant disadvantages to the KeyMouse. It is my experience that any minor problem can be tolerated for a couple of hours but after that it becomes annoying. Some of the potential problems I have identified below may appear to be trivial(I may be wrong and they may not even be problems) but in the long run, they become annoying.

I have made a number of assumptions and conclusions. Please let me know if I have got anything wrong.

How well does it work as a mouse and as a keyboard? This of course is crucial but they don’t spend any time talking about this. They only briefly show it being used. I would have liked to see a lot more. The video is impressive but avoids this crucial issue. I may be wrong but I didn’t find any specifications and these are important. I am going to make assumptions which may of course be wrong. Below are some of the problems I see. There are others but I want to be brief.

  1. I captured the photo above from their video. You will notice that the user’s thumb is bent. This is necessary so that the other fingers can reach the various keys. Here is a test you can do. Place your right thumb on the space bar. Keeping the thumb there try reaching the 7 key – it’s impossible even if you bend your thumb. So distance between keys is much less than the standard 19mm and also having to bend the thumb is clearly a problem.
  2. I think that during typing the palm will bump into the palm grip and inadvertently move the KeyMouse around.

Mouse Mode

  1. The user’s palm does not rest on the table and so mousing cannot be accurate.
  2. I assume (and I feel confident about this) that each KeyMouse is at least 200 grams. It would appear that one can get a good grip on the KeyMouse but 200 grams is a lot to move around. Over time this would be an issue.

Keyboard Mode

  1. The keys are vertically aligned and requires a significant learning and familiarisation period. I think this is a showstopper – people are too used to the standard QWERTY layout.
  2. They don’t specify the distance between keys. I assume that it is much less than the standard 19mm and once again is very different from a standard keyboard.
  3. Does the keyboard move around during typing? Even slightly? This may seem trivial but even if it moves slightly it is problem. It took a long time to solve this on Combimouse.  I think some keys are slightly angled and this could make the problem worse.



KeyMice website

This is similar to the Combimouse. They only advertise it for use with Android tablets. I think it has many problems but I have included it because of it’s similarity to Combimouse. Click here for the video.





Mycestro website

Leap Motion

Leap Motion website

Combimouse Funding

This blog discusses how funding for the Combimouse requires a combination of an investment and crowdsourced funding such as Kickstarter.

Investment is required to cover startup costs, including completion of the design, IP costs, emission standards testing, tooling(very expensive) and other costs. Angel List will be used.

When all these startup activities are completed we can then raise funds on Kickstarter. Kickstarter would only cover costs to purchase components for a production run and other costs related to manufacturing including, labour, transport etc.


There is a lot of interest in the Combimouse. The website has been viewed over 200,000 times and a Google search generates about 50,000 results.

In the past we have used Indiegogo for crowdsourced funding. On 27 August 2013, Kickstarter announced that they will be expanding to Australia soon. Research has shown that projects are more likely to succeed on Kickstarter and projects raise about 6 times as that raised on Indiegogo.

We have completed the proof of concept phase and are looking for investors to help us get to the manufacturing phase.

We are looking for an investor to fund startup costs.

We can only go into production once the startup tasks are completed. Startup costs include funding to complete the design, cover emission standards testing(FCC and CE costs US$30K), pay for tooling (tooling is the custom manufacturing equipment to make the plastics and custom keyboard – these costs need to be confirmed but are currently about US$90K) and other startup costs.

Only when the design is complete will we have an accurate manufacturing cost.

We require about US$250K for the startup costs.

This excludes manufacturing costs. Manufacturing costs include cost for purchasing components, labour costs and costs to distribute the product. Manufacturing costs will be raised via Kickstarter.

When the design is complete and we are ready for manufacturing we will have a good estimate as to the manufacturing cost. We will then launch an Indiegogo or Kickstarter crowdsource funding campaign to cover the manufacturing costs for the first production run.

So for the Combimouse project, Kickstarter can only fund production costs.

So Kickstarter is useful in that it significantly reduces the amount that is required from an investor.

Crowdsource fund raising for hardware projects is not suitable for covering development and startup costs as pledges have to be kept low. So pledges should be priced to  cover the manufacturing costs with a small profit. The full profit should not be priced in at this stage as the product has not yet launched and there is some risk to the contributors.

For example, if the pledges are priced with a $30 profit then we would need to get 250,000/30 = 8,300 pledges to cover startup costs. This is probably too much.

According to Kickstarter “To date the most popular pledge amount is $25 and the average pledge is around $70.”

The manufacturing cost is expected to be higher than $70 and and so for a successful campaign it is not realistic to price the pledges much higher than the manufacturing cost.

It is important to wait until we know what the manufactured cost will be before we launch a Kickstarter campaign. This will ensure, that we don’t make the first production to fulfil the Kickstarter pledges at a loss.

The Combimouse Story

It was a Friday night after a long day at work. I’m tired – there’s got to be a better way – I would like to use the keyboard and then just use the mouse. I took my angle grinder out and cut my keyboard in two…..

My name is Ari Zagnoev. I am the inventor of the Combimouse and CEO of Combimouse Pty Ltd.

Ari Zagnoev 250x250

I worked on the Combimouse as a hobby from 1999 to 2012.

January 1999
Combimouse invented.

2003 – Evaluated by Wichita State University
Click here to view the report.

September 2003 – Winner- Australian ITSecrets competition
The Combimouse was selected as a winner in the Australian IT Secrets competition. The award was presented to Combimouse CEO Ari Zagnoev by the Australian Minister for Communications, Information Technology and the Arts, Senator Richard Alston.

Click on the certificate to enlarge.

IT Secrets award

Click on the photo to see me receiving the award from the minister.

ITSecrets photo with Richard Alston


Roger Larcombe, Simon Herron and Susan Merli invest in Combimouse

Mid 2012

I started working full time on the Combimouse

Early 2013 – Design problems overcome

Technology is only now available to make the Combimouse feasible – including thin wall plastics, plastic mould flow analysis software, light weight notebook keyboard technology and ultra low power electronics.

Overcoming design problems has taken time. Especially making it light and mobile as a mouse AND immobile as a keyboard and at the same time making it manufacturable. For details please read the blog Combimouse Design Evolution. The solution of making it immobile as a keyboard was only conceived in early 2013 and has been patented.

April 2013

Funds raised on Indiegogo.

August 2013

Prototype works well and Combimouse can be used fulltime as a replacement for standard keyboard and mouse.




Why not disclose how the Combimouse Keyboard mode brake works?

The Combimouse right part is both a keyboard and a mouse. It has many conflicting requirements.

One of them is that it must not move around during keyboard mode while in mouse mode it must be very mobile.

This conundrum has taken many years to resolve. For a long time I had a solution which didn’t really work well and I tried to convince myself that it was okay. It was always a relief to go back to using a standard keyboard.

Clearly a proper solution was required. In early 2013 I though of a solution and have now patented it.

The solution is to make the right part supported on rubber feet during keyboard mode and supported by low friction sliders during mouse mode. It is automatic and the user doesn’t have to do anything.

One of the requirements for a solution was that it could not add any weight to the top keyboard part.

It works incredibly well.

I have patented it and shown it to a number of people.

I have not talked about it openly because I think that there may be companies who may be considering copying the Combimouse. I have disclosed a lot of other information already which has taken a lot of work and many years of work. For now I would like to keep as much information as possible confidential for as long as possible. I will be disclosing it within the next few months.

This is the reason why I have not shown any photos of the bottom of the right part.

Patents are useful because they offer intellectual protection and so there is incentives for companies to imagine new things. The problem is that big companies simply copy and with their big budgets leave the legal problems for their lawyers to sort out a few years down the road. That is assuming the small company can still afford to sue.

Another interesting thing to consider is that up until now only one person has asked me about this issue. There have been hundreds (possibly even thousands) of articles written about the Combimouse and of the ones I have read, no one has even brought up this issue. So, if I wouldn’t have mentioned it, it wouldn’t have raised any suspicions.

I was prompted to post this blog after “Marni” posted this comment on the Combimouse website “Since ergo’ keyboards attract few reviews, you need to have correspondingly *more* information on your site. Fear of buyers remorse is always present and with radically new products from small companies, that nervousness scales up.I think you have to be pre-emptive: provide as much detail as possible.”

This was a fair comment. My response is that I am not concerned that it will be an issue and for the next few months at least I would like to keep it confidential for the reasons above.

I would say that the product speaks for itself. It it works well then it will be successful. We are currently looking for an independent authoritative organisation to evaluate the Combimouse. If they see any problems they will report on it.


Gaming on the Combimouse

I am not a computer gamer and so I would be happy for you to comment and make suggestions.

I have had a number of conversations and done some research and this is where I see things.

Having a multi-button mouse for gaming I would think is useful.

Apparently MMO (Massively Multiplayer Online) games would be conveniently played on the Combimouse as the player needs to often quickly type out messages.

The Combimouse uses the scissors mechanism for the keys. This is the same technology used on a lot of computers including all notebook computers and Apple keyboards. This results in a very light keyboard

Apparently this is not the best technology for hard core gamers who prefer mechanical keys. According to this article:

“Most gaming keyboards use mechanical switches, which pair each key to its own spring loaded switch. They are designed to provide superior audio and tactile feedback.”

It is not possible to use mechanical keys on the Combimouse because they are too heavy. Weight of the right part Combimouse is critical and mechanical keys simply can’t be used. In addition a Printed Circuit Board would be required, which would also add mass.

Combimouse key layout and variations to support international options

Let us know what you think about this blog in the comments.

Here is the current layout of the Combimouse.

Click on the image to enlarge.

Combi layout

Note that some key positions had to be changed: Cursor keys, Delete, F1 to F12, back slash and forward slash.

There are four blank keys (user 1, user 2, user 3 and user 4) which will be user configurable.

The Mac control, option and command keys will be supported. We still need to confirm that the Combimouse can auto-detect that it is connected to a Mac.

There is a scroll wheel to the right of the M key.

Combi right 730 x

All keys on the Combimouse will be user configurable via a user configurable utility. So we are expecting that we will be able to support many different keyboard layouts.

It may be a problem putting labels on the keys because the mass of the right part is critical and even adding labels adds significantly.

Initially we will sell the standard US QWERTY version as shown above. We will then look into other versions.

One of the problems with many of the other keyboard layouts is the position of the Enter key.

As an example, the UK keyboard is superimposed over the Combimouse right part in the picture below. As you can see, the Enter would be located off the Combimouse. If the Combimouse part were to be made bigger to include the Enter key it would be too big.

“Hoggy” in the comments section has said that “I’m in the UK and I prefer the US layout for the better access to the enter key – I use it far more often than the hash”.

Combimouse over UK keyboard

As a comparison here is drawing of the Combimouse superimposed over the US keyboard. As you can see the Enter key is located on the Combimouse.

Combimouse over US keyboard

Printing the Combimouse plastic using 3D printing is not possible

The Combimouse uses ABS plastic and that is the material that 3D printers can print. The Combimouse Right Unit is a 1mm thick part.

Thin plastic parts is achievable using modern Plastic Injection Molding technology and has only become achievable in the last few years. This is suitable for mass production after a fairly expensive tool making process.

After a number of attempts as described below, I have subsequently found that it is not possible to print the Combimouse Right Unit using 3D printers. For example in this article they say “Even though you could use a minimum wall thickness of 1mm when using White, Strong & Flexible we recommend that you stick to 2mm. We would also never recommend making large portions of your model this thin because this would make it excessively delicate.”

Stereolithography with silicon moulds is an alternative option for runs of up to say 20 pieces. This costs a few thousand dollars.

For quick one offs it is best to make the Combimouse Right Unit by hand. It does take a few days, but with a limited budget and a relatively quick turnaround it is the best option during early prototyping until the design is finalised.

I attempted to print the right plastic using a 3D  printer that I had access to. I attempted to print in two orientations but they both failed. I also had limited access to the printer and so turnaround took very long – up to a week.

This printer has a resolution of 0.5mm whereas better printers can achieve 0.2mm. In addition this printer had a print area of 150mm x 150mm which is too small. So I had to print the part in three separate parts with the intention of joining them together.

So for now I will hand make the prototypes. This has a number of advantages including fast turnaround, low cost, represents what can be achieved in mass production plastic moulding and is good quality.

Initially we tried to print the part lying flat as shown here.

Flat print

However it lifted on the one corner which you can see in the following photo and so we aborted the print.

Flat print - lifted

We then attempted to print the part vertically. This took 8 hours.

Vertical print

When we removed the print from the printer a number of cracks appeared which is shown within the red ellipse in the photo below(the red ellipse is difficult to see – it is on the flat portion at the bottom.

Vertical print - cracked