Author Topic: First PCB for a beginner, where to start?  (Read 4085 times)

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Offline JLynchTopic starter

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First PCB for a beginner, where to start?
« on: July 26, 2021, 01:36:38 pm »
Hello, looking to make my first PCB and not sure where to start. I’d appreciate any guidance on what might be the best PCB design package for a beginner.

I’ve have things hobbled together on a breadboard and while things are pretty much working many questions remain including how to properly layout the circuit, selecting components the PCB manufacture has available and what’s the best software to use.

Thanks.
 

Offline MarkF

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Re: First PCB for a beginner, where to start?
« Reply #1 on: July 26, 2021, 02:57:10 pm »
What operating system are you using?

For Windows, I have found that DipTrace is very intuitive to me.

Download 'Freeware' here.

You can enter your circuit into the 'Schematic Editor' and then from the File menu 'Convert to PCB' to layout your PCB.
Or you can just insert components directly into an empty PCB from the 'PCB Layout Editor'.  The PCB Layout Editor can also display a 3D-View of your PCB so you can get an overview of space usage.  (I get extra 3D models from 3D ContentCentral.  You will need to create an account, which is also free.)

The 'free' version can do two layer PCBs and 300 pins.  I was able to layout my first PCB in one afternoon.


A lot of people on the forum like KiCAD.  I've never been a big fan of it.
These are the two most popular free software tools.


 

Offline TheAmmoniacal

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Re: First PCB for a beginner, where to start?
« Reply #2 on: July 26, 2021, 03:18:28 pm »
EasyEDA is quite nice for getting started, also Fritzing if you can find a free download now (they want 8 euros now).

DipTrace is quite intuitive if you're on Windows and more powerful than the two mentioned above.
 

Offline JLynchTopic starter

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Re: First PCB for a beginner, where to start?
« Reply #3 on: July 26, 2021, 04:24:16 pm »
Thanks for the suggestions, and have both Windows 8.1 and Windows 10 available.

I'll give them a try and see how things go, thanks again.
 

Offline tooki

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Re: First PCB for a beginner, where to start?
« Reply #4 on: July 26, 2021, 04:52:06 pm »
Another vote for EasyEDA. It's surprisingly capable and speedy for a web-based tool (an offline version is also available), and it really is easy to use.
 

Offline JLynchTopic starter

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Re: First PCB for a beginner, where to start?
« Reply #5 on: July 26, 2021, 06:14:58 pm »
I created an account in EasyEDA and started to layout my design and it does seem to be quite easy to use. However being new to all of this I’ve sort of run into another stumbling block.

My circuit is quite simple with only a handful a main components. Power comes from a USB type-B connector going to a 3.3v regulator. Then there’s a Bluetooth module and an H-Bridge driving a brushed DC micro motor.

When prototyping and stuffing components into my breadboard I find myself making use of these tiny little pre-built modules instead of individual chips. Now that I’m looking to build a PCB I need to ditch these modules along with all there supporting components - caps, resisters, diodes and whatever.

In prototyping I used a DRV8833 H-Bridge module, picture below, and it has a couple supporting components on the board - caps and resistors and such. What I don’t see is any back EMF protection for the motors.

Reading the DRV8833 datasheet it talks about a lot of protection but nothing specific to EMF.

“Internal shutdown functions with a fault output pin are provided for overcurrent protection, short-circuit
protection, undervoltage lockout, and overtemperature.”

I’m not sure if the overcurrent protection mentioned in the datasheet includes back EMF or not, does anyone know if I need to add flyback diodes in my circuit when using the DRV8833.

Also included a simplified block diagram of my circuit and once I’ve got the circuit drawn in  EasyEDA I’ll share that as well.
 

Offline tooki

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Re: First PCB for a beginner, where to start?
« Reply #6 on: July 26, 2021, 06:36:56 pm »
The little Chinese modules tend to have the most absolute bare-bones implementation that will work, not one compliant with manufacturer recommendations. (So they may not be as resilient or reliable as they could be.)

That IC happens to be a TI part, and TI is great about having EVMs (evaluation modules) for which they also provide the schematics, and reference designs (for products) that show the parts integrated as systems with other parts, for which they provide schematics and often PCB design files, etc. Take a look at the EVM for the part and do what it does, or if the part data sheet has a recommended PCB layout, follow it (as it will often have real-world values).

In the case of the DRV8833, the datasheet doesn't mention back EMF diodes, nor does the EMV schematic include them (and the EMVs tend to be balls-to-the-wall designs to let you push the component to its limits, so they include everything up to the kitchen sink), so I'd say it conclusively does not need them.
 

Offline JLynchTopic starter

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Re: First PCB for a beginner, where to start?
« Reply #7 on: July 26, 2021, 08:50:35 pm »
Tooki, thanks for the help with the EMF question and also for the great advise on TI’s evaluation modules. Nothing beats being able to see examples of chips used in real circuits from the manufacturer.
 

Offline james_s

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Re: First PCB for a beginner, where to start?
« Reply #8 on: July 26, 2021, 09:34:07 pm »
KiCad is pretty much the standard these days for the hobby and pro-sumer market, it's free and quite powerful. There is a bit of a learning curve but it isn't that hard, most EDAs use more or less the same workflow. Draw the schematic, create a netlist, lay out the PCB.
 

Offline JLynchTopic starter

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Re: First PCB for a beginner, where to start?
« Reply #9 on: July 27, 2021, 01:52:16 am »
While drawing schematics in EasyEDA seems quite straightforward I’ve found selecting components rather confusing, perhaps I’m going about it the wrong way.

I’m looking for a complete solution where I can send out my design and have completed PCB’s returned with all it’s components soldered in place yet a vast majority of parts I’ve searched for in the EasyEDA library seem to be out of stock or unavailable for JLCPCB production.

Is there a way to use / configure the parts library to only show what’s in stock and available?
 

Offline themadhippy

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Re: First PCB for a beginner, where to start?
« Reply #10 on: July 27, 2021, 02:02:16 am »
Quote
When prototyping and stuffing components into my breadboard I find myself making use of these tiny little pre-built modules instead of individual chips. Now that I’m looking to build a PCB I need to ditch these modules
Or treat the module as a component and make a  footprint  for it and use suitable headers to join your pcb to the module.
 
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Offline james_s

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Re: First PCB for a beginner, where to start?
« Reply #11 on: July 27, 2021, 05:20:41 am »
There are a lot of component shortages going on right now, you're likely to have a lot more problems with parts being out of stock than would be normal.
 
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Offline tooki

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Re: First PCB for a beginner, where to start?
« Reply #12 on: July 27, 2021, 03:35:40 pm »
While drawing schematics in EasyEDA seems quite straightforward I’ve found selecting components rather confusing, perhaps I’m going about it the wrong way.
It has the double-edged sword of user-created component symbols/footprints. On the one hand, it often makes it a lot quicker to find what you need, especially for the components favored by hobbyists. The downside is that the symbols/footprints may not be well drawn. (Though errors  happen on manufacturer-provided in symbols/footprints, too.)

I strongly suggest learning to make your own footprints, as it's often faster than hunting down the right one and carefully verifying its correctness. EasyEDA's symbols will be fine for jellybean parts, though, and their SMD footprints are well-made and follow a careful naming system, so even if you have to make your own symbol, for most things you can use an existing footprint.
 

Online jpanhalt

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Re: First PCB for a beginner, where to start?
« Reply #13 on: July 27, 2021, 03:49:46 pm »
Here are two sources of footprints:

https://www.snapeda.com/
https://www.ultralibrarian.com/

I believe EasyEDA can import from several of the other programs named.

BTW: I have used one of those programs to get an idea on occasion, but always use either the Eagle footprint or draw my own.  In Eagle, one can set the grid to facilitate getting things in the right place.   I assume Easy EDA has the same capability.
 

Offline fourfathom

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Re: First PCB for a beginner, where to start?
« Reply #14 on: July 27, 2021, 04:08:56 pm »
In Eagle, one can set the grid to facilitate getting things in the right place.   I assume Easy EDA has the same capability.

You can also set the grid and measurement units in KiCad -- both for component footprint creation and for board layout.  In fact, you can switch back and forth as you like during the process.
We'll search out every place a sick, twisted, solitary misfit might run to! -- I'll start with Radio Shack.
 

Online jpanhalt

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Re: First PCB for a beginner, where to start?
« Reply #15 on: July 27, 2021, 04:22:47 pm »
Likewise on Eagle.  It's a little cumbersome using dropdowns, but I set up hotkeys to facilitate it --  named "Toggle Grid" (F6) and "Grid Setting" (F5) on my keyboard.
 

Offline james_s

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Re: First PCB for a beginner, where to start?
« Reply #16 on: July 28, 2021, 01:10:02 am »
Unless you already know Eagle and use it, there's no point in learning it IMHO, ever since going subscription it is effectively dead, the hobbyist/maker community abandoned it en-masse.
 
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Offline admiralk

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Re: First PCB for a beginner, where to start?
« Reply #17 on: July 28, 2021, 02:00:18 am »
I strongly suggest learning to make your own footprints, as it's often faster than hunting down the right one and carefully verifying its correctness.

It might seem a pain at first, but after making a couple you will stop looking past the datasheet for new measurements. The same can be said for components. The pins on ICs always need to be in a different place every time I use them in a schematic. Sometimes even for the same IC in the same schematic.
 

Offline perieanuo

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Re: First PCB for a beginner, where to start?
« Reply #18 on: July 28, 2021, 06:00:58 am »
diptrace is fine, they give also non-bussines licenses if you ask them, eagle is fine too (on library side, you can find anything for beginner-level components for eagle and altium for example)
kicad etaetera, those are toys. i even manufactured 2-sided boards with eagle pro license, for quick projects altium is overkill to learn, but if you wanna go pro, start with something simple like i mentioned, then move to altium
 

Offline tooki

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Re: First PCB for a beginner, where to start?
« Reply #19 on: July 28, 2021, 07:42:32 pm »
It might seem a pain at first, but after making a couple you will stop looking past the datasheet for new measurements.
I don’t understand what you mean.

The same can be said for components. The pins on ICs always need to be in a different place every time I use them in a schematic. Sometimes even for the same IC in the same schematic.
Huh? You redraw IC symbols for each schematic?
 

Offline admiralk

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Re: First PCB for a beginner, where to start?
« Reply #20 on: July 29, 2021, 11:29:10 pm »
Well you have standard packages, so you do not have to make new footprints for everything. Datasheets give a recommended footprint and once you have done a couple, it is usually quicker to just get the measurements from the datasheet than it is to find one that is correct, and works in whatever program you are using.

It just takes a couple seconds to redraw a symbol. Just move the pins where you want them and adjust the outline, if needed. For example, in the attachment, I flipped the top and bottom pins on one of he 74LS373 so I could stack them and not have wires running all over the place. It is much neater to move a couple pins than have wires crossing.
 

Offline tooki

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Re: First PCB for a beginner, where to start?
« Reply #21 on: July 30, 2021, 03:12:29 pm »
Well you have standard packages, so you do not have to make new footprints for everything. Datasheets give a recommended footprint and once you have done a couple, it is usually quicker to just get the measurements from the datasheet than it is to find one that is correct, and works in whatever program you are using.
Well yes, but the thing that confuses me is you saying “…looking past the datasheet for measurements.” Getting footprints elsewhere is one thing, but I don’t know where else other than the datasheet one would search for measurements.
 

Online jpanhalt

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Re: First PCB for a beginner, where to start?
« Reply #22 on: July 30, 2021, 03:27:21 pm »
Well yes, but the thing that confuses me is you saying “…looking past the datasheet for measurements.” Getting footprints elsewhere is one thing, but I don’t know where else other than the datasheet one would search for measurements.

The whole phrase is, "you will stop looking past the datasheet for new measurements."  That means to me, stop at the datesheet and don't look elsewhere for measurements. 

I might add that some manufacturers, e.g, Microchip, put their recommended footprints in a standalone catalog, https://www.microchip.com/en-us/support/package-drawings.

 

Offline tooki

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Re: First PCB for a beginner, where to start?
« Reply #23 on: July 30, 2021, 04:43:21 pm »
Well yes, but the thing that confuses me is you saying “…looking past the datasheet for measurements.” Getting footprints elsewhere is one thing, but I don’t know where else other than the datasheet one would search for measurements.

The whole phrase is, "you will stop looking past the datasheet for new measurements."  That means to me, stop at the datesheet and don't look elsewhere for measurements. 
Yes, I understand the words, but I’m puzzled at what the alternative to the datasheet (or official manufacturer document like the one you mention) would be. To me, using the datasheet for measurements is obvious, so you need to spell out for me what the alternative to be avoided is, because I can’t think of any.
 

Offline fourfathom

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Re: First PCB for a beginner, where to start?
« Reply #24 on: July 30, 2021, 08:47:23 pm »
To me, using the datasheet for measurements is obvious, so you need to spell out for me what the alternative to be avoided is, because I can’t think of any.

Alternatives:
The KiCad libraries, SnapEDA.com, Ultralibrary.com, mouser.com/electronic-cad-symbols-models/, etc, etc.

If I use one of these sources I still need to check the dimensions.  I do build my own footprints from time to time, using the datasheet measurements.
We'll search out every place a sick, twisted, solitary misfit might run to! -- I'll start with Radio Shack.
 


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