1. OCAU Merchandise now available! Check out our 20th Anniversary Mugs, Classic Logo Shirts and much more! Discussion here.
    Dismiss Notice

Help required - need to replicate a circuit

Discussion in 'Electronics & Electrics' started by vs355, Mar 25, 2020.

  1. vs355

    vs355 Member

    Joined:
    Apr 28, 2006
    Messages:
    25
    I have a couple of circuits that I need to replicate (primarily 1). As an electrician, I have a limited electronics knowledge, other than identifing some components and assembling boards/circuits.

    So - the primary circuit I want to replicate consists of a bunch of resistors, capacitors, a couple of transistors - and a 16F688-1 microcontroller (all SMD - as space is critical). The tough thing about this project, is that I cannot get the exact information as to what the circuit needs to output. As such - with that microcontroller - is it possible to read the code that has been written, and reverse engineer it from that.
    Just to appease any concerns about copying somebody else's work. The main issue is that the company that previously produced these - closed their doors 2 years ago. As such, these simply cannot be purchased - or the information found.
    Sorry for being a little vague on details, if anyone believes they can assist in this, please PM me, and I can provide some more info (and am willing to pay for help on the project).
    Thanks
     
  2. Technics

    Technics Member

    Joined:
    Apr 29, 2002
    Messages:
    2,024
    Location:
    Brisbane, AU
    Reversing and replicating the circuit is usually trivial at that level of complexity.

    It is possible if the code protection has not been enabled. If it has been enabled (and it often, but not always is on commercial products) then you can't just read the firmware. There have been various ways to bypass this protection discovered on some PICs (using methods like programming voltage glitches and selectively erasing the protect bit on decapped chips I.e https://www.bunniestudios.com/blog/?page_id=40) but as far as I'm aware that device is not particularly susceptible to those methods. So you would need to see if code protection is enabled.

    This is unlikely to extinguish the copyright on the work. It's likely someone still technically owns that asset. It's hard to know from the information provided but it may be easier to simply recreate the functionality of the device from scratch.
     
  3. OP
    OP
    vs355

    vs355 Member

    Joined:
    Apr 28, 2006
    Messages:
    25
    Thanks for the reply
    Ideally if i knew what the output required was (or the input to the device) - then it could be rebuilt from scratch (using the same or other components). These are not something built in any qty - so not exactly commercial, but as you say - you would assume the code is read protected. (slim chance it isnt)
    How would i go about trying to read the chip to see if it was protected?
    Copyright - I get what you mean, but when i spoke with someone about that, he said there is precedence around that sort of thing, but to avoid any issues - if you can read the code/understand what/how its doing it - then you can redo it in another way (basically what you are saying). When its to be replicated, it will be packaged differently anyway.
     
  4. ShadowBurger

    ShadowBurger Member

    Joined:
    Feb 19, 2008
    Messages:
    1,986
    Location:
    Melbourne
    Curious to hear what it is. Could a replacement be designed simply by knowing what it's supposed to do?
     
    ArmoureD likes this.
  5. Technics

    Technics Member

    Joined:
    Apr 29, 2002
    Messages:
    2,024
    Location:
    Brisbane, AU
    You would just need to try reading the chip with a PIC programmer. There are a lot of different ones around. There might be an ICSP header on the PCB for factory programming or it could require removing the chip. Then use the software for the programmer to try and read the chip. It will either tell you it's protected or (i think) it may just read back zeros for PICs.

    I'm not an IP lawyer and I'm assuming that whoever you spoke to isn't either. It seems to be that at best it could be considered an orphaned work. That doesn't mean it's free to reproduce. You could still be open to a claim from the copyright holder at a later date. You would probably need to be able to demonstrate that you acted in good-faith and made an effort to contact the rights holder. This would be possible via company records for the place that closed down (directors etc.). That aside, I don't have a personal axe to grind here and understand where you are coming from. It's not like you are causing a great deal of actual harm by copying an abandoned product. It's more to make you aware of potential consequences of copying the work for your own sake.
     
  6. theSeekerr

    theSeekerr Member

    Joined:
    Jan 19, 2010
    Messages:
    3,339
    Location:
    Broadview SA
    There is some precedent for "clean room" implementations being legit - basically having one person turn existing code into a complete specification of what the system does, then having another engineer, who has never seen the original implementation, implement that specification. But that's a lot of work.

    If the system is fairly simple in purpose you may be able to define a specification from just the states of the I/O pins of the microcontroller, in which case you're in the clear copyright-wise.

    EDIT: Copyright of electronics is a complicated thing.
    You can't copyright a circuit.
    You can copyright a schematic, but that doesn't prevent someone else reproducing that schematic as a circuit, it prevents them reproducing it as a schematic.
    You can copyright a PCB layout, but again, that only prevents reproduction of that layout (and very similar layouts), not functionally equivalent layouts of the same circuit.
    Code and its derived works (assembly, binaries) are absolutely covered under copyright, but you can't copyright an algorithm.

    You can patent a circuit, or a device that implements an algorithm, so long as it is novel. For a lot of trivial circuits this is unlikely to be the case.
     
    Last edited: Mar 25, 2020
  7. OP
    OP
    vs355

    vs355 Member

    Joined:
    Apr 28, 2006
    Messages:
    25
    Technics - all good - I appreciate your comments, and 100% with you about the copying.
    PM inbound
     
  8. merlin13

    merlin13 Member

    Joined:
    Apr 12, 2003
    Messages:
    2,015
    Location:
    back in BrizVegas
    So you're also going to have to pass on a lot (!) more info that just what the outputs are supposed to be doing.

    Like exactly what are these circuits actually supposed to be controlling - are they running door openers, industrial breakfast cereal box stuffers, rocket motors?...

    And under what conditions - are they also automatic/autonomous or operator controlled, driving machinery in hazardous zones and/or controlling dangerous hardware etc?
     
    ArmoureD likes this.
  9. ArmoureD

    ArmoureD Member

    Joined:
    Sep 12, 2002
    Messages:
    725
    Location:
    Earth
    It may help us if you could tell us what this top secret device actually does, or is supposed to do?
     
  10. OP
    OP
    vs355

    vs355 Member

    Joined:
    Apr 28, 2006
    Messages:
    25
    Quick update - Technics (being a complete legend), is helping me through the project. Fear not - its not the next 'top secret' device to destroy the world................
     
  11. ir0nhide

    ir0nhide Member

    Joined:
    Oct 24, 2003
    Messages:
    4,433
    Location:
    Adelaide
    So what is it then?
     

Share This Page

Advertisement: