• Techniques

Reverse-Engineering an Old Patent


Reverse Engineering

Reverse Engineering is a form of cheating when used in industry to copy someone's product and produce it as your own.

Reverse Engineering is a tool used to better understand someone else's product or verify that your product is better and different.

Reverse Engineering is an essential tool when you need to design counter measures against things that are causing harm. For example: In WWII, the German's had a coding device that made communications traffic secure. Once this device was Reverse Engineered and understood, codes could be broken at will.

The most important aspect of Reverse Engineering is the ability to return a device to its owner with them having no clue that you looked inside. In fact, if you are clever enough, one does not even need to take it out of the shipping box!

A really important application is restoring vintage systems to new when there are no manuals, schematics or sometimes, parts available to repair a system. Sometimes all you get is a carbonized PCB and expected to make 10 just like it! The primary examples are Nuclear Reactors used in power-stations.

Nuclear Power Station electronics were mostly designed in the 1960's and 70's. Many, if not most of the manufacturing firms are either out of business or were purchased by other companies; in either case, spare parts, expertise and operational data are no longer available.

The Reverse Engineer will need to take what they have and either repair or redesign replacement component from scratch to keep the existing stations safe and operational.

Reverse Engineering par excellence

One of Martin Sala's top skills is gaining understanding of how and why something works, how to enhance, exceed or defeat a design.

By utilizing tools of the trade, or in many cases, inventing new tools, an unknown device (or system) can be analyzed, broken into sub-components and re-constructed. For example, in the design of an ultra-capacitor, does the competitor's design infringe on the design waiting to go into production?


Here one sees the capacitor on the left. The right hand image is a digital x-ray. There is some detail, but the how it is built is not easily discernable.


Now if you take a CT (Computed Axial Tomography) scan, it becomes obvious how this device is built. This image data can be further manipulated to show specific sections of the device, material density, and even spectrographic information (what is it made of?).

Reverse Engineering is a sub-set of Non Destructive Evaluation (NDE) and can be used to figure out how a product is failing, how well is it being produced or just "what does it look like inside?"


This is a slice through half of a Diesel Particulate Filter (DPF) . The filter is made of a ceramic material that allows exhaust gas to flow through the walls, but not microscopic dust particulates. The inlet channel is plugged at the opposite end. The outlet channel is plugged at the inlet end. This forces the gas through the walls, leaving the particles behind. If even one outlet plug is missing the over-all efficiency of the DPF suffers. In the pre Martin Sala days, the only way to check a DPF was to saw it open; if it was good, you just wasted product.

Using a CAT scanner, it is easy to see where the plugs are missing, the quality of plugging and even the integrity of the DPF walls. Martin Sala has designed systems that will automate the process, so as a DPF passes through the scanner, a GO/ NO-GO test can be applied.


A multidisciplinary engineer, where my passion is Hardware Reverse Engineering. Place a piece of equipment in front of me from 1969 with a burned-out crater in the middle and no documentation because its manufacturer is out of business and I will figure out how it worked, redesign with contemporary components and give you two back that are exact form, fit and function.