The "sanding the tops of chips" technique is (was?) quite widespread in the
UK when the Commodore Amiga was a popular system and every wannabe hardware
supplier wanted to supply a sound sampler for it.
Ours was a simple system, and it would have been fairly easy to copy, but
our advantage was in our sampling software. We had echo, reverse, reverb,
tone control, speed-up, slow-down, and more features that I have long
forgotten. With the sanded tops we survived un-copied for about 18 months -
more than enough time to recoup our development costs.

-Jim


-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of
William "Chops" Westfield
Sent: 08 June 2008 08:24
To: Microcontroller discussion list - Public.
Subject: Re: [PIC]: How to protect a small circuit from being hacked?


On Jun 7, 2008, at 11:16 PM, Vasile Surducan wrote:
> I have doubts someone will bother to copy the firmware of a simple
> product, it's much easy (and less expensive) to understand the
> functionality of the product and write own firmware.

I knew a guy that made and sold a little PIC-based temperature  
logger.  He went to the trouble of sanding the chips so that would-be  
copiers would have more trouble duplicating the design.  I thought it  
was pretty silly; if I want to copy such a device, I don't need to  
reverse-engineer it; I can just create it from scratch...

BillW

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