And then KAM Industries, maker of commercial software that serves a similar role, tried asserting their 'patent rights' over doing just that.
When the author of the open source railroad controller asked for additional information about what claims were being infringed, KAM sent him an invoice for $203,000, claiming that the 7000 or so users of his software resulted in damages of at least $29/each.
KAM then sent a request to the author's academic sponsor (unrelated to his independent model railroad work), requesting copies of all his email and other correspondence. To most observers, these actions would seem to be nothing more than dirty tactics meant to rattle Jacobsen into compliance.
Several more threatening letters arrived. Finally, in January of this year, Jacobsen responded by pointing out that he didn't believe the KAM patent would withstand a challenge in court, noting that there was plenty of prior art, including his allegedly infringing software, which was available before KAM filed their patent application. He also pointed out that KAM's lawyers must have known this all along. In February, KAM's lawyers responded by claiming that they know of no invalidating prior art, and that they still viewed Jacobsen's work as infringing on their patent rights.
This is all still ongoing. It isn't clear that KAM will cease harassing Jacobsen, even with the knowledge that their patents are likely illegitimate.
But it is abundantly clear that patents like this hurt the efforts of those trying to make the world a better place by producing tools for others to use (for free in this case). It is equally as clear that even small companies can use their patents as bludgeons against individuals.
The continuing saga (as well as all correspondence to date) can be followed at Jacobsen's website. Let's hope Jacobsen's software doesn't get shuttered by patent interests like RProxy did.
There are a number of useful reforms that could make the patent system a bit less abusive. If you want to do something about this type of absurdity, you can certainly try writing a letter to your Senators and Congressional Representatives. As always, feel free to cut and paste anything from this website when you compose your letter (a letter focusing on your favorite reform is a useful strategy) -- everything at Right to Create is in the public domain.