Need some advice on releasing information...


Hello everyone,

As some of you know, I have sold a few expanded HP48G calculators. What I would like to do is release the information I have on the upgrades, and in particular, on how to open the HP48 without causing it damage. Of course, I had already posted an earlier version with some photos, and it was in fact based on a method that already existed on However, the methods were not precise, so it was not too difficult to recognize the calculator as having been opened. Over time, I have improved upon the technique and am now able to open and close an HP48 in such a way that, and unless you know exactly what to look for, you will likely not be able to discern an unopened HP48 from an opened one. This improved method is well documented.

I have also written a memory upgrade guide that fixes a number of mistakes found in existing memory upgrade guides. There is also no known guide for memory upgrades using a single 512KB chip and using all of its memory banks. Nor is there a guide for upgrades of 1MB or larger. I have written instructions for these upgrades as well.

With this information, pretty much anyone can fix their own HP48 or make memory upgrades to it if they are willing to invest some time and patience.

So now to the problem...

When I sell my HP48 calculators, I do my best to disclose any and all pertinent information about the calculator, especially if it has been modified. However, I cannot speak for anyone else. And what I want to avoid is the situation where someone does a poor job fixing the problems of a unit and pass of his unit as a working unit, only to have an unknowing buyer purchase it and have it break down some short time later. I am trying to imply that the information I have will revolutionize the HP48 industry. However, up to this point, any information on servicing HP48 calculators can be best described as sparse.

At the same time, I like to share information as others can benefit from it.

So... any advice?


I am not a lawyer, of course, so this advice is from a hobbyist perspective, with an eye toward commercial applications. That warning being given, I would note that the dollar amounts involved per unit, and the low numbers of units in the 48g eBay pool make it cost ineffective to actually sue someone based on any license you might devise. So "the trick" you'd like your license to "do" would be to dissuade someone who didn't have the requisite skill from marketing an inferior product based on your work. But unfortunately, licenses like the GPL are based on copyright. The protection of copyright extends to the expression in a work, like the style of poetry, and doesn't cover inventions or methods. Patents are designed to protect those things. Short of a patent on your repair method, again a cost-prohibitive step, there's no way to actually guarantee you would have the legal force to stop someone. There is also no guarantee you would get a patent if you applied for one.

So I would go ahead and put license language in that prohibits commercial use of your idea without talking to you first. The hope would be that the shoddy operator would be dissuaded by that. However, nothing will stop someone who is either too stupid to take note of the license, or else too smart to know that the license is meaningless, from doing whatever they liked with your work. But both types would also have to be too callous to care about your concerns, and slipshod craftsmen as well. That's a lot of "ands" strung together. So, like I said, I'd just stick the language in and hope for the best.



The Crative Commons licenses may be of interest:

Edited: 2 May 2006, 5:15 p.m.


I don't think Han is trying to protect any intellectual property he may (or not) have in the techniques he has documented. He's concerned that his techniques may be used to conceal incompetent modification of a calculator from a buyer who might not detect that the calculator has been opened.

Han you cannot take responsibility for how people use the fruits of your labours. That some may use it to advantage themselves at the expense of others does not diminish its value to those who would use it scrupulously. If your information is available to all, you give neither the buyer or the seller an advantage. The fact that one party may not use your information is hardly your problem.



I understood what he wanted. IP in some form is the only way he could possibly control the fruits of his labor, for whatever reason. Since the available IP protection mechanisms are either inappropriate or cost-ineffective, my advice boils down to your clearer, simpler statement. 8)


I would like to thank everyone who responded. Perhaps the best course of action is to place some sort of license on the document and hope that readers will "do the right thing" when it comes to servicing and selling HP48 calculators. And of course, hopefully buyers can also educate themselves about HP48 calculators in general.

I think I will also make some additions (to help out buyers) in the form of tips on how to detect that an HP48 has been serviced (or at least opened).

Thanks again!


[begin shameless plug]

I have a couple more expanded units that will go on eBay in the future, along with a complete set of photos documenting the entire upgrade process. Also to be included is an upgrade guide which will include information on opening and closing the HP48 so that it is almost indestinguishable from an untouched HP48. The guide also fixes some errors found in existing guides, and will delve into the process of 1MB and higher-capacity upgrades. Just for fun, these units will be in a no-reserve bid format as opposed to a fixed price format.

[end shameless plug]

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