Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [reverse-engineering]

The process of taking a completed system and determining details of its design by analysing it; may have legal limitations or ramifications in different jurisdictions.

354 questions
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How does this circuit work? 48VDC relay and 1.2VDC battery from 230VAC

In order to repair a programmable timer plug, I'm doing some "reverse engineering" on it, it's not for the cost (about $5) but more for learning and recycle thought. I draw the scheme but can't figure out how it is working. With only some…
ROUGEXIII
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Patented hardware architectures

I have seen patented hardware designs at the level of generic digital block such as shift registers, flip-flops and adders. If a chip maker were to include such a design deep within an ASIC, how can patent holders uncover copyright infringement? Do…
Ang Zhi Ping
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How hard is it to reverse-engineer a two-way protocol for a beginner with a logic analyzer?

I recently bought a Tacx Flow trainer, which has a handlebar computer, with a 6channel RJ-11 cable between the trainer and the handlebar computer. The computer reads pedal frequency, power and speed, and is also able to adjust the trainer's brake --…
meastp
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What is this circuit in motion detectors?

I have used several off-the-shelf mains voltage motion detectors over the last couple of months. Different makes and models. This kind of thing: Often I have the issue that when they are off, they are not really off, i.e. the relay output still…
AndreKR
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Connect to "gold plate" connectors of existing PCB

I got a Bluetooth heating thermostat that I want to modify. The board has an ATmega 169PA, and I identified JTAG and ISP "connectors". They all look like those five round golden plates in the upper right of picture. Their distance is about 2.54 mm…
matge
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Earth Grounded 12V DC System

I'm very confused about this design i've come across in the field. A data acquisition system is powered by a 12V ACDC power brick. But then inside of the chassis is a DC-DC converter, also isolated, where the output GND is tied to the chassis, and…
BobaJFET
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Reverse engineering alarm keypad protocol

I'm trying to reverse engineer the protocol that an old home alarm system uses to communicate with the keypads. Connected via 4 wires: GND 13.2V DATA CLOCK I've managed to connect the wires to a logic analyser. Here's a snapshot of a periodic data…
Muxa
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Missing Component Pieces from a PCB

This PCB is from a old Sharp 1999 TV I have been reverse engineering lately; also sorry for any bad images. I have noticed that there are some "missing" components in the holes of: D4002, D4003, D4001, D4004, and C4002. Are there certain…
Sigma6RPU
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Missing Connector Pieces

There are missing connector pieces in this PCB that I was working on and I swear that there was no connector there in the first place, so I ruled out me going insane.I circled the connectors in gray. Are these connector pieces for something else…
Sigma6RPU
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Best materials to prevent reverse engineering of PCBA components?

I have an overmolded PCBA on a cable with passive components only. Some of the components are hard to identify, but I'm still concerned about the possibility of competitors trying to reverse engineer it. What are the best materials I can put on the…
user9272
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Reverse-engineering camera flash charger

I am trying to understand how exactly the voltage from a 1.5 V battery gets connected to a 1000+ V capacitor inside these disposable cameras. Is there a specific chip designed to act as a voltage amplifier and diode or do capacitors act as a sponge…
Firobug
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What could this IC be? Trying to reverse engineer a board

Studied EE, haven't used it in 10 years, so pretty rusty. Part 1: the board and how it's connected I'm looking at a very simple current controller that drives 3 different current levels based on a switch. Here's what the board looks like on the…
reedvoid
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Reverse Engineering: TTL/LVTTL signal direction

I just ordered my first scope (a Rigol DS1054Z) and have been thinking about some interesting experiments/learning projects to perform with it. Thus far most of my experience has been in building circuits/MCU + FPGA programming. One thing I'd like…
Nevermnd
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Switching circuit for changing HIGH- / LOW-level-trigger

On my smart home controlling PCB I want to add some relays. As I want to be flexible with signaling I want to add a jumper to be able to switch between HIGH and LOW level triggering the relay (3V3 from a RPi). Since I have no idea how to change the…
alve89
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Need help in populating omitted USB interface component values on an infrared cam

Having this Qunali IR cam which has a USB connector left out at the assembly and comms only via LAN. Probed Data lines, and I got 0.9V fluctuated readings. It seems to send something out there. So was wondering if anyone could lead me to what…
Gunay Anach
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