Reverse engineering schematics from a scanned 2 layer board - Page 1
Forum section: electronics / projects

author: somuchtyler
author_rank: Contributor
timestamp: December 30, 2020, 10:02:22 pm
content: Hey guys, I am trying to reverse engineer the schematics from scanned in images of a board. What would be the best way of deriving schematics from a board like this? I was thinking of doing this through photoshop and just using the magic wand and turning all the same nets the same color. I was just wondering if there is a more eloquent way of doing this?

author: somuchtyler
author_rank: Contributor
timestamp: December 30, 2020, 10:04:20 pm
content: here's how far I got:https://imgur.com/a/y5qqQQX

author: S. Petrukhin
author_rank: Super Contributor
timestamp: December 30, 2020, 10:23:31 pm
content: I think it's easier to take the datasheet on the chip and there will be a ready-made reverse.

author: dietert1
author_rank: Super Contributor
timestamp: December 30, 2020, 10:32:58 pm
content: I remember taking images of top and bottom, mirroring one of them, coloring them (red and blue) and mounting them on top of each other with transparency, all in Paintshop Pro. It becomes something like an X-ray image and will be easier.Regards, Dieter

author: somuchtyler
author_rank: Contributor
timestamp: December 30, 2020, 10:33:23 pm
content: Quote from: S. Petrukhin on December 30, 2020, 10:23:31 pmI can't find the datasheet, but I can find the chip on taobao

author: S. Petrukhin
author_rank: Super Contributor
timestamp: December 30, 2020, 10:42:38 pm
content: Quote from: somuchtyler on December 30, 2020, 10:33:23 pmWhat is the name of this chip?

author: somuchtyler
author_rank: Contributor
timestamp: December 30, 2020, 10:53:00 pm
content: Quote from: S. Petrukhin on December 30, 2020, 10:42:38 pmZQ5621 QFN32

author: S. Petrukhin
author_rank: Super Contributor
timestamp: December 30, 2020, 11:08:24 pm
content: Quote from: somuchtyler on December 30, 2020, 10:53:00 pmUm... really some strange beast...

author: somuchtyler
author_rank: Contributor
timestamp: December 31, 2020, 12:08:56 am
content: ok so does anyone have any suggestions?

author: S. Petrukhin
author_rank: Super Contributor
timestamp: December 31, 2020, 12:45:36 am
content: Quote from: somuchtyler on December 31, 2020, 12:08:56 amIf you need to copy the PCB without restoring the circuit, you can put it as a background on the document layer, adjust the size and circle the tracks. If you need a schematic diagram, then there are few components and the scheme is simple - it is easy enough to restore the trace. But using the rendered PCB, it is easy to see the connections - by highlighting the tracks, they will highlight all the connections.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: December 31, 2020, 02:01:29 am
content: Just open a schematic editor, create a part for the mystery chip, and draw it. This is not a very complex board.

author: somuchtyler
author_rank: Contributor
timestamp: December 31, 2020, 02:02:39 am
content: Quote from: S. Petrukhin on December 31, 2020, 12:45:36 amI was hoping theres some software I can use... I mean I can do it manually in photoshop but I was hoping I could say "hey this is a through hole" so whatever is on the other part of the board is going to belong to the same net

author: Mechatrommer
author_rank: Super Contributor
timestamp: December 31, 2020, 03:52:51 am
content: Quote from: somuchtyler on December 30, 2020, 10:04:20 pmgood job! you've done 80% of the work, now i got your IP already!need to halve the size in photoshop since original sized psd if 25MB, even halved sized its still 6MB, so i just post the reduced jpg version here... i think its just a breakout board of some mcu with built in regulators.

author: S. Petrukhin
author_rank: Super Contributor
timestamp: December 31, 2020, 08:31:38 am
content: Quote from: somuchtyler on December 31, 2020, 02:02:39 amYes, this is exactly what any PCB editor will do: when you draw a board, the selection of any track or via will highlight the entire connected net.