PCB etching and basic schematic

Thread Starter

ELECTROFLUX

Joined Aug 7, 2015
38
Hello everyone,
i have never ever done a circuit from scratch before, so i would like some advice from someone more experienced, just in case i made some basic mistakes....
I found a nice video on YouTube, and i wanted to recreate it, i will only use a single layer, so there will be lots of zero Ohms resistors placed as "bridges" where the traces cross each others.
On the first screenshot, you can see the original circuit from YouTube, the second picture is my attempt to copy it, will this works???
Many thanks :)

Selectable Latching Relay 1.jpg


PCB.jpg
 

jpanhalt

Joined Jan 18, 2008
8,058
Your circuit and the screen capture from YouTube are not identical. For starters, the number of transistors is different. We don't even know whether the circuit you copied works. Anyone can post whatever garbage they want on You Tube.

John
 

Thread Starter

ELECTROFLUX

Joined Aug 7, 2015
38
Hi Jpanhalt,
i just double checked, i can assure you that the number of transistors matches, but i had a problem to make the whole KiCad schematic, fit my screen in a way that would be readable, i try F11 but doesn't work, i did also look for a way to hide some of the toolbars before taking a screenshot, but i couldn't find that option either, i can take multiple pictures in a way to show the whole thing, because if i reduce the size to fit the available part on my screen, the various components would look too small to be seen.
I believe the guy that posted this project is a "genuine" one, also this particular project, it's not really something "exceptional", as those alleged perpetual motion machinery or things like that, those would surely need to be taken with a pinch of salt, but i don't think this one it's comparable to a scam of any sort, i trust this guy

I also forgot to add, that yes i did modified the position and paths of some components, in a way to reduce drawings, but the end result should be the same? I mean, if i get VCC from one point instead of another, it's still VCC, so it should works anyways?? Please correct me if i am wrong.
 
Last edited:

MaxHeadRoom

Joined Jul 18, 2013
19,145
As to the layout, it is bad form for a 'wire' to cross a component.
Why the connection across a resistor?, if you need to cross another wire, just don't use a Junction.
Also use the circuit common and power +ve to indicate the supply, also with Kicad, you will need to identify these symbols as the circuit power supply.
For a good free screen capture try GreenShot.
Max.
 

AlbertHall

Joined Jun 4, 2014
8,493
We can only see a section of your schematic - we need all of it.

Your circuit and the screen capture from YouTube are not identical. For starters, the number of transistors is different. We don't even know whether the circuit you copied works. Anyone can post whatever garbage they want on You Tube.
The utube picture does not show the finished schematic - it is drawn painfully slowly over squid knows how many videos.
 

Thread Starter

ELECTROFLUX

Joined Aug 7, 2015
38
Thanks for the suggestion MaxHeadRoom, i have never heard of this "GreenShot", i will surely give it a try tomorrow.
As to the zero Ohms resistors on top of the wires, as i wrote, being this a single layer circuit, i couldn't think of anything else to simplify the design, i am not even sure if drawing long traces in order to avoid crossing them would be possible.
I am using "power flags" as suggested by KiCad to identify the power supply, i then added those additional GND and VCC+ notes, to more easily identify which one was what.
 

MaxHeadRoom

Joined Jul 18, 2013
19,145
Thanks for the suggestion MaxHeadRoom, i have never heard of this "GreenShot", i will surely give it a try tomorrow.
As to the zero Ohms resistors on top of the wires, as i wrote, being this a single layer circuit, i couldn't think of anything else to simplify the design, i am not even sure if drawing long traces in order to avoid crossing them would be possible.
I am using "power flags" as suggested by KiCad to identify the power supply, i then added those additional GND and VCC+ notes, to more easily identify which one was what.
If you don't want to run a circuit wire right across a schematic etc, Using a Global Label, reduces the clutter.
BTW, GreenShot is activated by the Print Screen key it is just an app.
Max.
 

jpanhalt

Joined Jan 18, 2008
8,058
We can only see a section of your schematic - we need all of it.
The Youtube picture does not show the finished schematic - it is drawn painfully slowly over squid knows how many videos.
The You Tube didn't run on my machine. All I can see is the first image that shows 6 PNP's and 6 NPN's. The TS image shows 4 of each type. There appears to be something off screen to the right, but my AAC periscope is broken and I can't see it.

John
 

Thread Starter

ELECTROFLUX

Joined Aug 7, 2015
38
We can only see a section of your schematic - we need all of it.
The utube picture does not show the finished schematic - it is drawn painfully slowly over squid knows how many videos.
I will try to sort this out tomorrow if i can, looking for that GreenSpan suggested earlier to achieve it.
On this YouTube video, you can see the whole schematic, the problem is that many times he got his hands covering large parts of it, or does close ups where you can only see a small part of it, this screenshot i used is the one which could offer a view of the whole circuit, but with just a few traces missing (the unlatching from the switches).
The 3 different circuits, are basically a copy of each other, A, B and C looks almost identical, but obviously the unlatching wire would be slightly different, as button A will unlatch B and C, then button B would unlatch A and B when pressed, etc.. i hope it make sense
 

Thread Starter

ELECTROFLUX

Joined Aug 7, 2015
38
Ok guys, thanks for all the replies so far, it's already past midnight on this part of the world and i cannot think so straight anymore, i will try to fix the problem with the screenshot tomorrow, stay tuned in ;)
 

Thread Starter

ELECTROFLUX

Joined Aug 7, 2015
38
Back again :)
I did try to install that Greenshot thing, but once i start it, just shows an error all the time (something quoting "side by side"), reinstalled multiple times but nothing to do, anyway, i found a way to take a whole screenshot by using KiCad, it was named differently ("Plot"), so i couldn't spot it at first sight.
Here it is:

Plot.png
 

Thread Starter

ELECTROFLUX

Joined Aug 7, 2015
38
It looks like you are using NPN transistors where the screen capture shows PNP and vice versa. From the screen capture it appears that A, B and C are identical so you might consider using hierarchical sheets. This allows you to reuse the same circuit for A, B and C.
https://en.wikibooks.org/wiki/Kicad/eeschema/Hierarchical_Sheets
Thanks, i had troubles rotating/mirroring the transistor's symbol, but i added a note on each one to specify the position for emitter/base/collector pins, the note should be correct?
I briefly previously had a glance at this option, but i would need to read more to understand how to use the hierarchical sheets, it looks as a shortcut that can make my job easier, instead of copy and paste with some corrections as i did here
 

Thread Starter

ELECTROFLUX

Joined Aug 7, 2015
38
Do you guys think that this circuit might work, or there is some gross design's error i made?
I know i will have to be careful with the zero Ohms resistor's bridges, probably by keeping the resistors higher and with a wider space between the pins, so there will be more room for the traces underneath.
 

Thread Starter

ELECTROFLUX

Joined Aug 7, 2015
38
Even though it's single sided, you can design it as double sided board. The component side would just consist of traces that are jumpers in disguise.
Hi KeepItSimpleStupid,
do you think these "bridges" can cause some big issues i am not aware of? Maybe overheat or something?
As i will keep them higher and wider, i don't think it might cause a short-circuit, but maybe there is something else i am missing?
 
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