Reverse engineering is the process of taking something apart to understand how it works in order to duplicate or enhance the object. In electronics, reverse engineering involves taking apart an electronic item to analyze and understand the circuit boards, components, and programming.
kicad is an open source electronics design automation (EDA) software that allows engineers to create schematic diagrams and printed circuit board (PCB) designs. kicad reverse engineering refers to taking apart a device and analyzing the kicad files to understand the schematics, layout, and functionality in order to recreate or modify the design.
Reasons for Reverse Engineering kicad Designs
There are several reasons an engineer may want to reverse engineer a kicad design:
Learn from Others
Analyzing an existing kicad design can help engineers understand schematic design techniques, layout considerations, component selection, etc. This allows them to improve their own skills.
Recreate Discontinued Products
If a product is no longer manufactured but the kicad files are available, reverse engineering allows recreation of the item. This is useful for repairing old electronics or manufacturing new units of a discontinued device.
Improve Existing Products
Engineers can add features, fix problems, reduce size, or lower costs by modifying an existing kicad design through reverse engineering.
Verify and Audit Designs
Reverse engineering is useful for verifying that a device functions as intended based on the schematics. It also allows auditing kicad designs for errors.
Check for Intellectual Property Theft
By comparing a suspicious device to an original kicad design, reverse engineering can identify potential intellectual property violations.
Reverse engineering helps security researchers identify vulnerabilities in hardware devices by understanding how they function from the schematics.
Files Used in kicad Reverse Engineering
kicad stores designs as various file types which provide different information when reverse engineering:
Schematic Files (.sch)
These files contain the schematic diagram with symbols for each component and wiring connections. This provides a clear understanding of the circuit functionality.
PCB Layout Files (.kicad_pcb)
The layout files have details on PCB stackup, layer definitions, component footprints, etc. This assists with analyzing the PCB design.
Netlist Files (.net)
Netlists outline component connectivity in the schematic. Examining the netlist helps identify critical traces and signals.
3D Model Files (.wrl)
The 3D model files are useful for determining component dimensions and placements on the PCB layout.
Fabrication Files (.gbr)
Fabrication files like Gerber files contain information on PCB copper layers, solder masks, silkscreen, etc. This helps with PCB manufacture.
Library Files (.lib)
Component library files provide details on device footprints, symbols, 3D models, etc. This assists with identifying parts.
Processes and Tools Used
Reverse engineering a kicad design involves several processes along with various software tools:
Visually inspecting a printed circuit board provides information on components, layout, markings, etc. Magnification helps identify small markings and parts numbers.
Software like KiCad or Eagle is used to open the schematic files. Analyzing the schematic provides an understanding of circuit functionality.
PCB Layout Analysis
The PCB layout is examined using KiCad or other EDA tools to identify stackup, layer details, component placements, trace routing, etc.
The netlist can be reviewed using text editors or software tools. This reveals connectivity between components and signals.
3D modeling software allows visualization of board and components. This assists in measurement of clearances, distances, etc.
Testing and Probing
Testing devices while probing signals assists with reverse engineering. Oscilloscopes, logic analyzers, and other equipment is used.
Chemical stripping of coatings helps access covered components and PCB layers during analysis.
Challenges with kicad Reverse Engineering
While reverse engineering kicad designs provides valuable information, there are some challenges engineers can face:
- Lack of component identification markings makes parts difficult to recognize.
- Complex multilayer PCBs with minute traces are harder to analyze.
- Proprietary components may have hidden functionality difficult to decipher.
- Encrypted FPGA or microcontroller code stops firmware analysis.
- Inadequate testability makes probing signals problematic.
- Poor documentation provides little assistance during analysis.
Applications and Examples
Here are some examples of how kicad reverse engineering has been utilized:
- Recreating vintage synthesizer circuits from old kicad designs due to lack of availability of original ICs.
- Cloning discontinued DIY open source projects by downloading and analyzing kicad