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Is reverse engineering illegal? Answered

Is reverse engineering illegal? Well, if you then go on to sell your version? For example, in an upcoming instructable I'm modding some electronics, well, without revealing my instructable here's an equivilent example: Lets say I buy a little robot at the store, it has motors and the case and everything. Only problem is, it runs on AA's and you want rechargable batteries. Also, the wireless module for some reason is external and is super ugly and annoying. You crack open everything and you find that the needlessly large circuitboards only have about 20 (somewhat) easy to find components that adds up to like 2 dollars. Following traces, you recreate a schematic from the PCB (already did this, that was fuuunnn :P). Now you reengineer the board (still same schematic) so that it's much more compact, you've added a little charging circuit (and correspond boost circuit, replacing a couple of AA's with a lithium ion), and you made it all fit inside the robot (no wireless module just hanging around outside the robot. Now, essentially the schematic is the same, but you've added stuff like the boost circuit and charging circuit. You've also added a few customizing features that make it more special (adding LEDs, microcontroller, cough cough etc.). Would it be illegal to sell a board/kit (incase other people want the board and can't solder smd to good) for people to modify there own robot (same model etc.). Also, the schematic from the reverse engineering is very similar to an example circuit in the main chip's datasheet, and a few other parts are common sense (like some resistors here and there, LEDs, a few extra filtering caps), so the company's circuit is nearly identical to the datasheet, is this illegal to sell?


if you sell like 10 of those boards, you have 0 chance of being sued now, if you sell thousands of your boards, the chance skyrockets there are many other factors, like how you advertise your product (or if you just sell it to your friends)

Yeah, but...

Even if the replacement board was completely different, that doesn't protect him from lawsuits. As a law prof friend once told me: " You can sue anyone at any time for anything. "

I.E., a company's decision to sue might have nothing to do with the strength of their claim. They could sue even if you created a completely original product. You can hide under a rock... or you can be an entrepreneur, and take a chance.

So, by all means, do the "due diligence"-- more research, look for similar hacking-for-sale examples, speak to a patent attorney, maybe to the manufacturer themselves. But I doubt they'd care, if the circuit mirrors the datasheet.

Plus, selling thousands of replacement boards also means selling thousands of their robots. Sure, some companies are stupid enough to bite the hand that feeds them, but most are smarter...


9 years ago

I like the hypothetical in your post.... ;-).... Lets say I buy a little robot at the store...

...Also, the schematic from the reverse engineering is very similar to an example circuit in the main chip's datasheet...

You've put your finger on it right there. Many in many devices, circuits are straight from the datasheets; that's not a new thing. It's a good indicator that that portion isn't patentable.

A toy's appearance can be "trademarked." Functional differences span a gray area between trademark, patent and the "new kid in town", known as "intellectual property." I'd read up on what constitutes a patent, since patents can be granted on new uses of existing technology. Some "mashups" might count as new uses, for instance.

But to get back to the question: No, a mundane charging circuit probably isn't patentable.

How many millions of battery operated toy robots have been built? Other than appearance, can you identify anything unique? Does it wifi with other robots? Is it a Disney character?

To be sure, don't copy anything exactly; change the look of the robot; in the charging circuit, change the PCB layout and make a few trivial changes to resistor values, add an extra RC filter, etc.

If you make a motorized robot with blinking eyes, no one can argue there isn't plenty of "prior art." If any toy robot patents exist, their toy probably violates the patents as well...


well, there isn't much to change in the circuit, it's mostly 10k resistors, 0.1uf caps, 2 unknown pnp transistors (which I will replace as I see fit, that a big enough change?) and that's pretty much it. Adding onto the robot situation, I'd still be using the robot case, motors, and sensors and everything. Oh, and I'd be radically changing the pcb layout.

Oh, you'll be including the existing robot in a kit? (yep, I see that in your post now.)

I don't see that as a problem, unless it's a trademarked character.

If it's a typical "Pacific rim" import toy, it's unlikely it's trademarked. They might even be willing to sell to you directly. Maybe without the PCB, although that's doubtful unless you're talking real quantities.

Re: the PCB--again, if it's close to the datasheet, just make it even closer...

No epoxy blobs? That's good...

Can you afford to be sued? That's what it comes down too.

You'll have to look up whether or not circuits can be copyrighted, that's the determining factor.