Source Code

The primary inherent advantage of an Open Source unit, which is also modular and designed to use common, widely available parts, is that it can be economically maintained over the long term.   All components used are easy to replace and can always be sourced, in the near or distant future, from many different suppliers. 

Because the parts can be sourced from suppliers other than the original manufacturer/designers, the incentive to engage in planned obsolescence is broken.  

Additionally, there is no need for the company to stay around for the very long term in order for the unit to continue operation very long term.  70% of companies in the business of home improvement products are out of business within 10 years, and 50% are gone within only 3 years. 

Long warranties are therefore useless anyway.

It is important that building elements be effectively maintainable over the long term to get a good return on investment.  Buildings are a long-term proposition.

If a unit lasts 30 years instead of 5 years, that means it's average cost of operation is 1/6th as much, per year (even less, if you  factor in interest).  This has a major impact on return on investment.  The OpenERV has only one wearing part, the bearings, and they can be replaced easily.  Therefore, there is almost no natural limit to how long it can last, because anything that wears out or is damaged can always be replaced.

The use of additive manufacturing and open source components is no philosophical matter.  In order for components to be easily obtained by many suppliers, they are both necessary.  No machine of this kind can be produced without a few custom mechanical parts.  The only practical way to make such custom parts widely available from someone other than the original manufacturer is to use common additive manufacturing processes and publish the digital manufacturing files.

Additive manufacturing tends to be important in open source hardware. 

 This is because even if you have the design of a conventional component, you can't practically make it because it costs $50,000 to make the mold or set up the assembly line to make the component.  So you are still stuck buying it from some company that has invested that capital.  Additive manufacturing can, for the first time in history, change this.  Not only is the tooling cost (the cost to make at least one of a unique part) very low, but the actual machines are relatively cheap.  

Fortunately, for electronics, the ecosystem for components has a lot of good commodity parts that are widely available, and there are a lot of companies that stock them and can make you a custom board surprisingly cheaply straight from the design files.

Some aspects of the source code are not ready yet, and publishing partially completed stuff has no real value in this particular context.  But, it will be here:

The STL files (zip file) for the beta are ready now.  (unfortunately Github does not support files of significant sizes).

Micropython source code packages (you can also get this directly off of the Raspberry Pi Pico built into a unit): Not ready yet to a useful degree.

Electrical schematic (there is a copy in the manual, too): Not ready yet and in any case there is no rush since it's only useful for maintenance and there are no units out there.

There will be a list of replacement parts and their part numbers etc. in the manual.


The TW4 is open source, with all files and the firmware licensed under the CC BY-NC-SA 4.0, which allows non-commercial use without a license.  If you want to make and sell them, talk to us first.  The source code is provided for the purpose of enabling maintenance and as part of the strategy to eliminate the incentive for planned obsolescence, not to enable cloning of complete devices.  If you would like to print your own unit for personal use, we can come to an agreement, but I would recommend the kit, I plan on making kits.