Arduino Forum

Using Arduino => General Electronics => Topic started by: Carlcox89 on Jan 22, 2013, 12:53 am

Title: first pcb try
Post by: Carlcox89 on Jan 22, 2013, 12:53 am
Hi, i spend some minutes trying to do my first pcb, basically it's an arduino with a 3.3v regulator so i can connect a nrf24l01 chip.
If it's alright i will buy some ferric chlorid so i can make my first pcb.

Please give any hints, opinion, advice...
Title: Re: first pcb try
Post by: larryd on Jan 22, 2013, 01:05 am
Lots of demos on YouTube.
On your PCB make your Vias the same size as the other pads (if the software allows you to).
I make the IC & Vias pads 80mils, Regulators 120mils, Switches 100mils.
I always elect to make single sided boards with jumpers rather than double sided.
I sometimes add a few transistor/resistor/capacitor pad footprints just in case I want to add a modification later.
Title: Re: first pcb try
Post by: DVDdoug on Jan 22, 2013, 02:03 am
I guess some people are having success, but my plan is...  :D I'm NEVER going to attempt it again! :D

I made some boards many years ago.  It was messy, the boards looked homemade, the drilling was not very accurate, and I don't remember what other problems I had, but it wasnt' much "fun".  It probably took a couple of attemps to get a working board.   

When I went to college, there was a lab where I could get boards made from my supplied artwork.   Since graduating from college, I've built several projects permanently on plug-in "breadboards", and sometimes I use perfboard and hand wire.   In the past I also used some wire-wrap.

If I ever decide to make a custom board again, I'll use a service like ExpressPCB (http://www.expresspcb.com/ExpressPCBHtm/Costs.htm) to get the boards professionally made. 
Title: Re: first pcb try
Post by: MarkT on Jan 22, 2013, 02:14 am

Hi, i spend some minutes trying to do my first pcb, basically it's an arduino with a 3.3v regulator so i can connect a nrf24l01 chip.
If it's alright i will buy some ferric chlorid so i can make my first pcb.

Please give any hints, opinion, advice...


Pin 8, GND, appears not to be connected (or is there a ground plane?)  The ground trace for the crystal load capacitors
seems to be unconnected too.

No 0.1uF ceramic decoupling capacitor(s) on the Vcc and AVcc pins?
Title: Re: first pcb try
Post by: pwillard on Jan 22, 2013, 02:41 am
DVDdoug, your experiences are very personal.  It is my opinion that not everyone needs to take your advice and give up making their own PCB before they even try.

With a little patience and experience you can make perfectly good boards at home.

Example: (http://i1206.photobucket.com/albums/bb442/muaddee/IMAG0132_zpsb351680f.jpg)

1) Making a PCB at home is not fun, for you.  Others may like it as I do.
2) PCBexpress is a sort of good with the bad experience due to proprietary tools.  There are probably much better examples of of good places to get PCB's made...   like maybe ITEAD.

http://imall.iteadstudio.com/open-pcb/pcb-prototyping.html (http://imall.iteadstudio.com/open-pcb/pcb-prototyping.html)

3) I don't run around telling people "Don't eat cabbage because it sucks and smells funny."  I allow people to figure things like that out on their own.
4) They said they were going to buy some ferric chloride... so farming it out does not seem to be in the plans.

Here is how I make mine:
http://pwillard.com/files/DIY%20Single%20Sided%20PCB.pdf (http://pwillard.com/files/DIY%20Single%20Sided%20PCB.pdf)


As others have said... you can't really do double sided PCB's at home without at least getting better experience at single sided... so you want to design your board so that IF you need TOP SIDE traces,  they are all the shortest possible straight lines you can run as "jumper wires".

Designing PCB's is sort of like solving a complex puzzle.  It can be a rewarding experience if you let it become one.  Using surface mount parts is usually done to save space... but since you are using many through hole parts already... It might be easier to just use ALL through hole parts... that way, everything is on the same side... but that is a personal choice... up to you.

One design idea... Avoid using all sorts of angles... pick only a few, like maybe 45 and 90 for all traces.



CARL: I'm assuming you are trying to use a laser printer toner transfer method...  I've done it for a long time you... if you have questions... feel free to ask.

Title: Re: first pcb try
Post by: Docedison on Jan 22, 2013, 09:40 am
@ OP A good "First Attempt" And I did that work from design to turnkey work for nearly 35 years.
@pwillard.. GREAT looking work, home made but not obviously so. There were no location marks on the individual boards for cutting and that was the only real giveaway.
Spot on constructive criticism too.
Bob
Title: Re: first pcb try
Post by: fungus on Jan 22, 2013, 11:15 am

@ OP A good "First Attempt"


And done with Fritzing. That should annoy somebody... :)

Title: Re: first pcb try
Post by: tkbyd on Jan 22, 2013, 11:16 am
Hear, hear, pwillard!

I've had a lot of fun over the years, making my own PCBs.

Now... they may not be brilliant, they may not often use SMT, they may not be "professional"... but they clear up my proto-boards for the NEXT project, and are reliable and robust. (How many times has my CCTV enabling circuit gone down because that wire has come out of the proto-board, AGAIN!?... note to self: Get the PCB for that finished, installed.)

Guidance for, to me, reasonable compromise between hopelessly amateur and hopelessly expensive tools and techniques...

http://www.arunet.co.uk/tkboyd/ele1bp.htm
Title: Re: first pcb try
Post by: jonisonvespaa on Jan 22, 2013, 01:44 pm
hi pwillard

nice boards, have you tinned the copper with something if so what do you use?

just wondering what are the squares in the left board are for? some sort of noise reduction maby ?

also whats the bottom right board for?

cheers
Title: Re: first pcb try
Post by: pwillard on Jan 22, 2013, 04:41 pm
Quote
nice boards, have you tinned the copper with something if so what do you use?


I use COOL-AMP powder.  http://www.cool-amp.com/cool_amp.html (http://www.cool-amp.com/cool_amp.html)

Even just a 2 ounce bottle would last you a very long time.

I also sometimes use MG chemical's "Liquid Tin" that comes in a pre-mixed and ready to use bottle, but I like the results a bit less than what I get with Cool-Amp powder.   Using Cool-Amp does require a bit more work though.

Quote
just wondering what are the squares in the left board are for? some sort of noise reduction maby ?


No, that is my way cope with 2 things... 1) if you have a ground plane, you save on etching time... less to etch away.  2) If I have a large ground plane, my Lexmark printer starts to make a very thin toner layer... which will show as bleed through etching.  The small squares and gaps break up the ground plane but also keep a lot of copper un-etched.

Quote
also whats the bottom right board for?


That is a for my outdoor heated RAIN SENSOR.  It's basically a 2-wire mesh that can detect the conductivity of rain drops.


Note: The board on the LEFT is actually my ATMEGA 8,168,328 programming fixture.
Title: Re: first pcb try
Post by: CrossRoads on Jan 22, 2013, 05:17 pm
Posting a schematic helps for the group review.
For instance, it would make it more obvious that there are no decoupling capacitors on Vcc, Avcc, or Aref.
Gnd pin 8 on the chip does not appear to be connected.
The crystal caps are connected to ground thru the reset switch. etc.
Title: Re: first pcb try
Post by: JoeN on Jan 22, 2013, 06:21 pm

If I ever decide to make a custom board again, I'll use a service like ExpressPCB (http://www.expresspcb.com/ExpressPCBHtm/Costs.htm) to get the boards professionally made.   


The latest DipTrace has an order online option right on the menu that sends the board data to Bay Area Circuits, checks against their design rules, lets you pay from PayPal, etc.  Total convenience, not as cheap as Chinese manufacturers, but you will get it faster and the board I did worked first time and looked great.  3 small boards is usually about $30 or so plus reasonable fast shipping so prototyping out of DipTrace (free 500 pin version available for asking and 300 pin for not asking) is really very straightforward and convenient.
Title: Re: first pcb try
Post by: CrossRoads on Jan 22, 2013, 06:52 pm
Is diptrace the program that is being discussed elsewhere in the forum, it bypasses some of the windows security settings as part of the installation?
Title: Re: first pcb try
Post by: CrossRoads on Jan 22, 2013, 06:58 pm
I used expressPCB for my first board, a simple 20 LED board arranged in 3 sections with 3 transistor drivers, a 4th transistor as a line receiver/signal inverter, and 7805 for 12V to 5V power supply. The signal was the TX from another board going to a promini, as was the 5V. The promini drive the 3 transistors. (A single 7406 would have worked as well, but I had this drawer of 1980's era transistors I wanted to finally use).
When my designs got more complex, I moved to eagle.  The expressPCB rubberbanding leaves something to be desired. Eagle was awkward at first, so many parts options, took some getting used to.
Title: Re: first pcb try
Post by: JoeN on Jan 22, 2013, 07:03 pm

Is diptrace the program that is being discussed elsewhere in the forum, it bypasses some of the windows security settings as part of the installation?


Yes, I think I brought it up on another thread and that comment was made.  But I am not going to stop commenting on it because someone says it bypasses a security feature of Windows during install.  If true, it means their installer sucks, it doesn't mean the software is spyware or anything like that.  Parallax uses DipTrace now for their PCB design work.  Given how popular Eagle is, I would have never tried anything else if it wasn't for their 100x160mm limitation and huge price jump to get beyond it.  DipTrace works well, has no set PCB size limitation (the free version is limited to 300 pins, 500 pins if you ask to be upgraded to this second also-free edition for the price of your email address).  I installed DipTrace on Windows 7 and I didn't have to elevate rights so I am not sure exactly what the installer is doing that is non-kosher but it sure doesn't require more than normal user rights.

http://www.parallax.com/productinfo/diptrace/tabid/922/default.aspx
http://www.diptrace.com/partnership.php  

http://www.youtube.com/watch?v=Wbr0RWb3kkU
Title: Re: first pcb try
Post by: CrossRoads on Jan 22, 2013, 07:37 pm
Quote
3 small boards is usually about $30


That price only seems to be for the

"Engineering Student Special

This is our EE Student Special

You must register with a school/university email address to be able to order this special.

Any orders without a school email address will be rejected."

http://store.bayareacircuits.com/engineering-student-special/

I don't see a way to get 3 boards for $30 elsewhere.

I suppose I could game the system and order thru my college alumni address, and set up another paypal account with the same address- but my ship-to address would be a giveaway as it's in a different state.

The Weekend Warrior looks appealing
http://store.bayareacircuits.com/weekend-warrior-special/
"$125 Gets you

?1 PCB Design
?As many of the design that will fit in 90 square inches"

A 3.4" x 2.25" board is 7.65 in^2
So I could get 10-11 boards for $125 in 7 days with USPS shipping included.

For comparison:
Same 10 boards from iteadstudio (2 layer <10cm x 10cm) are $24.90 + $25-30 for fast DHL shipping.
Title: Re: first pcb try
Post by: JoeN on Jan 22, 2013, 08:27 pm

Quote
3 small boards is usually about $30

I don't see a way to get 3 boards for $30 elsewhere.


It's not the online deal, it's a deal the system gives you when you make the board in DipTrace, check design rules, etc., and submit it directly through DipTrace.  They don't even list it as a deal, but whatever pricing schedule they are using beats the online price always, as far as I have seen so far.  The price depends on the dimensions and particulars for the board.  Here is my invoice.  This is a very small board with a QTFP-100, two PLCC-32 sockets, a crystal, a few resistors and caps, and two connectors (programming - 10 pin and output - 16 pin)

(http://arduino.cc/forum/index.php?action=dlattach;topic=144140.0;attach=34310)

Once you have your design, you just go to File > Order PCBs and you get this dialog:

(http://arduino.cc/forum/index.php?action=dlattach;topic=144140.0;attach=34312)

I sent this to them last Monday afternoon.  They shipped it today.   The last once I did (my first PCB ever) was very nice and worked great.
Title: Re: first pcb try
Post by: JoeN on Jan 22, 2013, 08:38 pm
One other thing, I totally am going to try out iteadstudio.  I recognize they have great prices.  But these are my first boards and they are experimental so getting 3 instead of 10 isn't a big deal for me.  Being able to order out of the program rather than trying to make sure I have sent all the correct files is a big plus to me.  I recognize that am paying for convenience and lack of experience here.
Title: Re: first pcb try
Post by: CrossRoads on Jan 22, 2013, 08:59 pm
For itead:
http://imall.iteadstudio.com/open-pcb/pcb-prototyping/im120418003.html
Go here, scroll down, and click Download.
Download & unzip the files for Eagle.
Put the .dru file in the eagle /DRU folder, and .cam in the /CAM folder.
(.drc file? I don't remember)

When your design is created, and you're satisfied with the error rule check (ERC) on the schematic,
and you're happy with the board design,
use the .dru file for the design rule checks on the .brd file. Fix any errors.
There are usually a bunch of Stop Mask errors, especially if you have any headers. I usually ignore them if I am satisfied with the markings presented.
(You can right-click & SMASH components, then move names around, resize them, etc. If you get too confused, Unsmash & start over with a fresh Smash. Really helpful if you delete a name by accident)

When satisfied, create the gerbers. From the .brd file, its a 2-step process.
(this reads more complex than it is)
File:CAM processor, new message box opens
File:Open:Job:select the itead .cam file
then click Process Job. Bunch of files get created, 13 total.
You can download a free viewer from viewplot.com to check them out.
When satisfied, put the 13 created files (but not your .sch and .brd files) in a zip file, that's you send to itead.

Order PCBs, you'll get a Order #  back.
Send the Order # and your zip file to pcb@iteadstudio.com


(this is all from memory, but its pretty close)
Title: Re: first pcb try
Post by: SirNickity on Jan 22, 2013, 09:18 pm
Somebody in another forum suggested MyRO as a fab house.  Any experience here?  I really, really like the boards I get from ExpressPCB.  I also like the software and the "just do it" built-in ordering.  The price is ridiculous though, so I'm evaluating services that can produce top-notch boards, quickly (I'm impatient), for a little less than an arm and leg.  Being able to route inside the perimeter would be nice, too.

My humble opinion to the OP:  I would highly suggest you use a more capable design app, and clean up the traces a little.  Try and keep as much space as possible between any two traces, and any pads.  There are several of your traces that skirt right up to other elements, when there's plenty of open area that you could be using.

Here's my latest project -- maybe it can provide some inspiration.  Or maybe I just swapping project photos with people.  :-)
Title: Re: first pcb try
Post by: JoeN on Jan 22, 2013, 09:21 pm

Here's my latest project -- maybe it can provide some inspiration.  Or maybe I just swapping project photos with people.  :-)


I like your boards.  You are a lot smarter with additional silkscreen printing and copper pours than I am.  I hope I get to be that good sometime soon.
Title: Re: first pcb try
Post by: rvasque on Jan 22, 2013, 09:32 pm
Quote
Somebody in another forum suggested MyRO as a fab house. 


I've used Myro. Been happy with their boards, I think their quality is better than PCBCart.

I would say Myro has same level of quality as US made boards (PCBFabExpress) -- but without the expensive US pricing.

It's a few dollars more expensive than other China fabs, but not a deal breaker. I'll use them again when it's time to re-order.

Title: Re: first pcb try
Post by: SirNickity on Jan 22, 2013, 09:49 pm
I like your boards.  You are a lot smarter with additional silkscreen printing and copper pours than I am.  I hope I get to be that good sometime soon.


Thanks! :-)  It just takes hours... and hours... of detailed work.  And a willingness to throw a design away and start over when the layout starts taking more effort than it should.  What works for me is to camp out on the couch in front of the TV with my S.O. and poke away on my laptop.  This set took me about a month, working for a few hours a night.  Not every night, but many of them.  I'm kind of OCD though.

I've used Myro. Been happy with their boards, I think their quality is better than PCBCart.


Good to know.  The published prices look almost too good to be true, but that's probably just shock after paying $300 for the last batch. :smiley-eek-blue:  I had to click "Submit" with my eyes closed on that one.
Title: Re: first pcb try
Post by: rvasque on Jan 22, 2013, 09:55 pm
I regularly order $300-$700 worth of boards.  My last order with Myro was $650 (for 100 boards, gold immersion pads and fingers, cutouts, routed shape, it's a big board). Still cheaper vs. US based companies. 

Myro is based from Canada, but their actual PCB fab is in China.
Title: Re: first pcb try
Post by: jerseyguy1996 on Jan 22, 2013, 10:49 pm
I just put in my first order at this place:

http://dorkbotpdx.org/wiki/pcb_order

They are supposed to come back from the fabricator in about a week.  Pretty good deal considering the fast turnaround and tight board specs.  It is also nice that I can just send them my eagle board file and they will take care of creating the gerber files from it.  Cost me about $14 for 3 double sided boards.
Title: Re: first pcb try
Post by: Carlcox89 on Jan 23, 2013, 04:04 pm
Well many thanks for all tips and help.
I dont know why pcb shows without pin 8 connected, since it's connected to gorund in the diagram view :o (maybe fritzing sucks)
I will try to do it single side only and will post diagram and pcb here so you can review it

@pwillard yes i'll use laser printer toner transfer method if i need some help i'll get in touch with you. thanks
Title: Re: first pcb try
Post by: Carlcox89 on Jan 24, 2013, 01:29 am
As you can see in the diagram, pin 8 is connected :o
why didnt fritzing connected it at pcb view ?
thanks
Title: Re: first pcb try
Post by: danb35 on Jan 24, 2013, 01:46 am

Is diptrace the program that is being discussed elsewhere in the forum, it bypasses some of the windows security settings as part of the installation?

They've commented in the EEVBlog forums that this was an inadvertent setting in their installer, and they've uploaded a corrected version.  FWIW.
Title: Re: first pcb try
Post by: CrossRoads on Jan 24, 2013, 01:48 am
You don't have that Gnd connected to the other grounds either.  How do you add a Ground plane?
Title: Re: first pcb try
Post by: Docedison on Jan 24, 2013, 02:09 am
RE Post # 26 Pin 8 is connected to the crystal loading capacitors.. Only there is no visible net label or a ground symbol. While the cad program (Fritzing) might connect the pin labeled ground on the IC to ground, the pin isn't labeled so you got exactly what you put down. If you label that net as ground and do a copper pour it will fix the issue.

Bob
Title: Re: first pcb try
Post by: Carlcox89 on Jan 24, 2013, 02:53 am
I'm trying changing it to single side now :)
question: what's the package for 1uF capacitor (options are from 100mil to 300mil THT electrolytic)
also for 22pf capacitor (options are 100mil and 200mil)

Also, i didnt understood exactly what you mean by labeling net as ground... (my native language is portuguese, so maybe that's the problem of understanding specifical/technical english words)
Title: Re: first pcb try
Post by: SirNickity on Jan 24, 2013, 03:27 am
Package sizes depend on the packages you choose.  I have 100nF caps in both 0.1 and 0.2" lead spacing, for example.  You have to check the datasheet for the part you intend to stuff the board with.

If I had to guess, I would pick 100mil for the 22pF and 1uF electrolytic, since that's about what mine are.  You can always bend the leads if necessary, although that's more difficult for electrolytics due to the typical form factor of the part.
Title: Re: first pcb try
Post by: CrossRoads on Jan 24, 2013, 04:00 am
"If you label that net as ground and do a copper pour it will fix the issue."
Assuming one knows how to do a ground pour in fritzing.   The pin and the caps do not look connected on the board drawing presented earlier.
Title: Re: first pcb try
Post by: Carlcox89 on Jan 24, 2013, 04:09 am
Ok, so i tried (hard) lol this is the result.
would you mind checking if everything's ok ?
Title: Re: first pcb try
Post by: CrossRoads on Jan 24, 2013, 04:17 am
Where are the 0.1uF caps on the VCC and AVCC pins?
Figure out how make a ground plane, ground pour, whatevet fritzing calls it. Top & Bottom layer.
Title: Re: first pcb try
Post by: Carlcox89 on Jan 24, 2013, 04:21 am
Oops, forgot to put those.
Ok, i'm going to do a little research on that.
Title: Re: first pcb try
Post by: Carlcox89 on Jan 24, 2013, 06:12 am
Ok, now it's where i start to freak out LOL
I already connected the crystal load capacitors ground directly to arduino gnd instead of going through the switch.
I added decoupling capacitors, is it like that?  :smiley-roll-sweat: (attached image)

About ground plane/pour, i couldnt find anything that would make me understand what i need to do.

(i've attached fritzing project just in case someone has it installed and is willing to show me how it can be done)
thanks
Title: Re: first pcb try
Post by: Docedison on Jan 24, 2013, 09:33 am
A "Net" is a set of interconnected points like ground. Nets get names from 2 primary places one is the symbols connected. For example a ground symbol is enough to create a net called 'ground'. The second source is the pin numbers assigned to an IC or other part.In the example I pointed out the error was in not editing the net created by interconnecting those 4 symbols, 2 caps a crystal and a processor.
Finally there will from time to time be net names you will create or modify to fix/add/modify circuit connectivity (the netlist).

Bob
Title: Re: first pcb try
Post by: pwillard on Jan 24, 2013, 05:22 pm
Ok, I took a few minutes and did the most painful think I can think of... I used Fritzing.  OK, My opinion of this tool is 1) it fills a need   2) It doesn't do a great job of filling that need  3) it needs to get beyond what I consider DUPLO block stage.   It lets you do bad things.  Ok, lets just say... I am not a fanatic about Fritzing and leave it there...

Step 1, I tried to make sense of you schematic... and realized it was unfinished.  Anyway... I will post what I did to see what it should have looked like.  Schematics are not always about "showing ALL wires" even though that is what you might think.  Using the convenient GND "net" and +5V "net" can greatly simplify a schematic... see my example.   Your drawing, sadly, showed signs of thing being moved and creating "crazy wires".  (Note: Fritzing file still has an error in Schematic... see if you can find and fix it.)

Step 2, I cleaned up your PCB.  Here's some tips... always try a few routing paths not just the first one you see... your first pass might not be ideal. be prepared to "rip up" work.  When doing single sided boards... always strive to keep jumpers to a minimum.

Also note: My "fixes" are not the BEST I can do... I only have so much time on my lunch hour.  I just wanted to show a cleaner PCB layout.  Notice that I use more of the board.  If you are going to have that much "real estate", no sense making all kinds of bendy wires...

Title: Re: first pcb try
Post by: SirNickity on Jan 24, 2013, 08:42 pm
Nice rework.  I'm 100% sure all my remaining complaints are directed toward the tool, not the designer.  ;-)

OP:  Do yourself a huge favor and give some dedicated PCB design packages a shot.  There are a few common ones that get mentioned around here.  Eagle being the most popular, but possibly most complicated, of the free(-ish) ones.  Fritzing is a nice tool to graphically depict a design you have on a real-world breadboard for others to look at, but IMO, not much beyond that.
Title: Re: first pcb try
Post by: CrossRoads on Jan 24, 2013, 09:19 pm
Nice job pwillard. That's way more than I am willing to do with that toy.

Carlcox89, are you planning to use the Analog pins? If so, you should disconnect pins 20 & 21, and connect 20 to a capacitor to Gnd.
The connection to 5V will be made internally if used, or you could use the internal 1.1V reference.
If the pin is hardwired to +5, you lose that option.
Title: Re: first pcb try
Post by: Carlcox89 on Jan 24, 2013, 10:10 pm
Many thanks pwillard for taking your hours ;)
It'll really help me understand what i did right and wrong.

@CrossRoads , i dont intend to use analog pins now, but maybe i need to use them in the future.
So i would have to break the 20&21 pins connection, and connect a capacitor (how much uf ?) to pin 20 (AVCC) to ground ?
thanks
Title: Re: first pcb try
Post by: CrossRoads on Jan 24, 2013, 10:20 pm
Yes on Aref. 0.1uF to Gnd, no other connection.
Title: Re: first pcb try
Post by: Carlcox89 on Jan 24, 2013, 11:11 pm

Yes on Aref. 0.1uF to Gnd, no other connection.

Aref ?
you said "connect 20 to a capacitor to Gnd."
pin 20 is AVCC :o
AREF is 21
So which one should i connect with a capacitor to GND?
Title: Re: first pcb try
Post by: SirNickity on Jan 25, 2013, 12:45 am
Both!
Title: Re: first pcb try
Post by: CrossRoads on Jan 25, 2013, 02:31 am
Vcc needs to connect ACVV, and connect both to +5V. Put a 0.1uF cap on both pins.
Put a 0.1uF cap frpm Aref to Gnd.
Title: Re: first pcb try
Post by: Carlcox89 on Feb 16, 2013, 12:27 am
Is this what you mean ?
Title: Re: first pcb try
Post by: CrossRoads on Feb 16, 2013, 12:46 am
Almost - don't connect Aref to +5, just a cap to Gnd.  It has internal connection to +5, or +3.3, under software control.
Connect pin 7 to 20.
This where a view of the schematic comes in handy.

If you can do a ground pour, or ground fill, or whatever the program you are using calls it, then you can delete the all over the place ground traces and just connect those pins to the ground plane instead. That will make for quieter signals too.

You have room on the board - I would add a diode in parallel with the reset resistor - anode to the reset pin, cathode to +5.  This will keep any spikes that occur from making the chip think its going into High Voltage programming mode (and look liket its just hung up to you). 1N4158 type of diode is sufficient.

Looks like you have 2 regulators? Would recommend caps on the 2nd regulator also. 1uF on input, 0.1uF on the output.

Do you have any plans to add pin names (D0, D1, etc) or part names (C1, C2, etc)? That really helps to make the boards look sharp.
Title: Re: first pcb try
Post by: Carlcox89 on Feb 17, 2013, 02:17 am
I've added capacitors to 2nd regulator and added label names for them.
you mind checking? ;)
Title: Re: first pcb try
Post by: CrossRoads on Feb 17, 2013, 02:25 am
Looks pretty good. Trace for pin 20 is kinda thin compared to the rest.  Maybe indicates it has not been routed yet?
Schematic turned out pretty good.
Still recommend a diode across R4 for reasons described before.  At least put pads in for it if you don't want to install it to start.
Title: Re: first pcb try
Post by: Carlcox89 on Feb 17, 2013, 02:34 am
I was kinda afraid of modifying the schematics because  first i suck at understanding them... but i think i can understand them by now.
About the thin wire, yes i didnt double click so it was a rastnest line instead of being a wire (corrected now)
diode just like that?
Title: Re: first pcb try
Post by: CrossRoads on Feb 17, 2013, 05:47 pm
Looks good.
Title: Re: first pcb try
Post by: Carlcox89 on Feb 17, 2013, 05:56 pm
No obvious mistakes ? Like wrong connections or such ?
i'm ready to try my first pcb etch

You mind also take a look at http://arduino.cc/forum/index.php/topic,149447.0.html
it's related to this pcb i'm making
Title: Re: first pcb try
Post by: CrossRoads on Feb 17, 2013, 06:40 pm
None that I see.
I still recommend a ground pour - that will save on etching material also as you only etch enough to isolate the pads & traces, and not clear out whole big sections of the board.
Title: Re: first pcb try
Post by: Carlcox89 on Feb 17, 2013, 07:19 pm
Is this what you are saying ?
i've choose GND as a ground seed and then did Ground Fill
i cant understand how it works and how i'm gonna etch my pcb like this
Title: Re: first pcb try
Post by: mmcp42 on Feb 17, 2013, 07:26 pm
that doesn't look good
the ground fill bit has worked
but it seems to have nuked all you lovely traces :(
Title: Re: first pcb try
Post by: Carlcox89 on Feb 17, 2013, 07:29 pm
i really dont know how to do this with fritzing, i think i leave it just like it was before... and maybe in the future use another program like eagle
Title: Re: first pcb try
Post by: mmcp42 on Feb 17, 2013, 07:47 pm
I would go for Eagle every time
takes a few extra minutes to get up to speed, but it's like moving from crayons to calligraphy (IMHO)

apart from anything else - there are so many people here who can help you with it
this problem would have been a doddle!
Title: Re: first pcb try
Post by: CrossRoads on Feb 17, 2013, 07:53 pm
That's the idea, but it seems to have the ground on one side of the board and the traces on the other, hence the 2 different colors (yellow-ish gnd, and reddish traces); from the jumpers you showed earlier I figured you were making a single sided board. Try it again with the ground pour on the same side as the traces. What you want is to just have the copper removed from next to the traces and around the pins, you can see where that took place arond the pads already.
Title: Re: first pcb try
Post by: Carlcox89 on Feb 17, 2013, 08:11 pm
Yes the board is single-sided... i really cant do that ground pour with fritzing.
i'm trying moving the wires to the other side of board and doing copper fill to see if this is what you mean.
Title: Re: first pcb try
Post by: Carlcox89 on Feb 17, 2013, 08:26 pm
One last time before i give up :D
Title: Re: first pcb try
Post by: CrossRoads on Feb 17, 2013, 08:30 pm
Ok, copper fill then. Have that and the traces on the same side of the board.
Then you end up like this, where the white is the copper that is removed and the red is the copper that is left.
This is for a surface mount board. You probably want everything on the bottom layer for easier soldering of pins to pads.
Title: Re: first pcb try
Post by: Carlcox89 on Feb 17, 2013, 08:34 pm
I did ground fill instead. see image above
it's that?
Title: Re: first pcb try
Post by: CrossRoads on Feb 17, 2013, 08:54 pm
No, that has a top & bottom layer. You want the ground fill on the same layer as your traces.
Title: Re: first pcb try
Post by: Carlcox89 on Feb 17, 2013, 09:05 pm
i really cant understand this :x
i've tried to export etch_copper_bottom so you can see the bottom only, but i dont think  that's what you mean
Title: Re: first pcb try
Post by: CrossRoads on Feb 17, 2013, 09:44 pm
That's exactly what I mean! That looks pretty good.
Last thing I would recommend is making the 90 degree corners on traces into a couple of 45 degree corners.
This is important in home etching because often the inside corner can be over-etched  leaving the resulting corner trace on the thin side.
Title: Re: first pcb try
Post by: 0AlphaOmega on Feb 17, 2013, 10:35 pm
Some nice attempts. Tinning makes a massive difference to the solderbility.

A little while ago, I came across an article, but can't find it right now. It used a CD printer to print the etch resist and the silk screen layers directly onto the board, pretty nifty. I think they used a simple two-edged jig to ensure registration. They were using a non-FeCl etch too (which is a pain to recycle and stains everything around).
Use good quality PCB drill bits and a drill post (dremel et al make them). If you allow the drill to self-centre, drilling is quite easy and can look good. Self centring requires the pad hole to be quite small). The technique is to visually align the drill/work, then as the drill nears the work, allow the work to move, and the hole in the pad will align with the drill, hold firmly and press through. Obviously works with smaller boards. Use of backing board leaves a good finish.
Title: Re: first pcb try
Post by: kajmaya on Feb 19, 2013, 04:11 pm
I have read this post with great interest. I'm new to the PCB layout and design. For those of you who are drilling your own boards. Where do I find a .08 bit in the USA. What size of bit or bits do I need? Where can I get them? I believe .08 is the correct bit size for most leads.

Thanks

Title: Re: first pcb try
Post by: Carlcox89 on Feb 20, 2013, 03:19 am
@  CrossRoads  thanks for the tip, i'm gonna do that :)
One question, when printing with laser printer, should i print the normal bottom or the mirror one ? I'm confused  :~
Title: Re: first pcb try
Post by: CrossRoads on Feb 20, 2013, 06:45 am
Try it both ways on paper, see which comes out the way you want.
The file you posted above is the traces as if looking "thru" the board. You want the one that is looking from the bottom of the board.
Title: Re: first pcb try
Post by: Henry_Best on Feb 20, 2013, 04:44 pm

For itead:
http://imall.iteadstudio.com/open-pcb/pcb-prototyping/im120418003.html
Order PCBs, you'll get a Order #  back.
Send the Order # and your zip file to pcb@iteadstudio.com



Do board manufacturers through-hole-plate vias or do I have to solder a wire through them myself?
Title: Re: first pcb try
Post by: Leon Heller on Feb 20, 2013, 04:49 pm
All board suppliers provide PTH.
Title: Re: first pcb try
Post by: CrossRoads on Feb 21, 2013, 12:28 am
Yes, itead takes care of the thru hole plating.
Title: Re: first pcb try
Post by: MarkT on Feb 22, 2013, 04:48 pm

I have read this post with great interest. I'm new to the PCB layout and design. For those of you who are drilling your own boards. Where do I find a .08 bit in the USA. What size of bit or bits do I need? Where can I get them? I believe .08 is the correct bit size for most leads.

Thanks




0.08?  Sounds very wrong in mm or in - perhaps you mean 0.8mm?

0.035" or 0.9mm is about right for a range of leads, thin leads and vias can be thinner than this.  eBay has quite a lot
of carbide PCB drills available, but some are ex-industry used drills from the look of things.  For fibre glass carbide bits
are the best.
Title: Re: first pcb try
Post by: AlxDroidDev on Feb 22, 2013, 05:22 pm
I have made several PCBs at home and I've been making them for a long time. Everytime I make one, it is better than the one before, because I find ways to optimize the processes involved: what is the best paper for toner transfer, the adequate temperature and time for the transfer, and so on. I like doing them and I enjoy doing them.

All my boards are single-sided, and I take care in revising the routing made by DipTrace (more on that later). I don't trust its auto-router blindly. A good PCB starts in the PCB layout: I know of the limitations of my process and I take care in specifying trace widths and clearance I can handle (18mil). I avoid jumpers. I revise DipTraces autoroutes and end up changing or correcting at least 50% of them.

For drilling the boards I use a Dremel tool exactly like this: http://toolmonger.com/wp-content/uploads/2007/04/post-dremelworkstation.jpg  (http://toolmonger.com/wp-content/uploads/2007/04/post-dremelworkstation.jpg) I have drill bits in 0.6, 0.8, 1.0 and 1.2mm.

I know my homemade PCBs could look a lot better if I were using photographic transfer methods, a better etching process and so on, but I like to keep it simple and cheap, so I use toner transfer with glossy magazine paper, transfered with a cloth iron and etched with (warm and filtered) ferric chloride. This is very cheap and very fast. For me, designing the board as well as I can is what gives me high sucess rates.

Here are a couple examples of PCBs I've made. Both are links to Facebook albums, but no facebook account is required:

1) Simduino (Simplified Arduino clone): https://www.facebook.com/media/set/?set=a.3248657275029.110252.1824874327&type=1&l=f89646a4f1

2) Arduino shield (with EEPROM + RTC + dig. temp. sensor): https://www.facebook.com/media/set/?set=a.3191611048909.108905.1824874327&type=1&l=a0e77a5b55


About DipTrace: I like it very much. I does everything I need (my needs are pretty basic and simple). Now that I've learned how to create custom components and patterns on it, there is very little I can't do with it.

Only TODAY I sent my first order to iTeadStudio, because the PCBs had to be double-sided and I needed10 of them.

In short, I find designing and making PCBs a great fun and I really enjoy making them.
Title: Re: first pcb try
Post by: Carlcox89 on Mar 02, 2013, 02:37 am
I've one doubt,
according to the schematics
(http://arduino.cc/forum/index.php?action=dlattach;topic=144140.0;attach=36393;image),
will the 5 pin header (in the left) behaviour like this ?
(http://www.vwlowen.co.uk/arduino/stand-alone/circuit.jpg)

because those 5 pins are to connect the CP2102 usb to serial with dtr line, so i can upload sketches without needing to press reset.
Will my schematics behaviour like the second one ?
Title: Re: first pcb try
Post by: swescrew on Apr 21, 2013, 03:48 pm
Hi, I have some questions.

I will try to build a breakout board for micro sd card (I know they exists but I want to build one myself, not ordering).
My plan is to attach a sd socket, tiny transistors and then in the end drill some holes so you could use jumper wires to attach the whole circuit board to your existing project. I will try to stick with surface soldering so the board could be very small and I don't have to drill so much holes.

I was wondering if it's possible to make a pcb that have that small lines? Don't know what the "lines" are called but will the iron chloride remove those or will they stay?

Tldr; How small and precious could you be when using the iron chloride method?
Title: Re: first pcb try
Post by: AlxDroidDev on Apr 22, 2013, 01:25 pm

Hi, I have some questions.

I will try to build a breakout board for micro sd card (I know they exists but I want to build one myself, not ordering).
My plan is to attach a sd socket, tiny transistors and then in the end drill some holes so you could use jumper wires to attach the whole circuit board to your existing project. I will try to stick with surface soldering so the board could be very small and I don't have to drill so much holes.

I was wondering if it's possible to make a pcb that have that small lines? Don't know what the "lines" are called but will the iron chloride remove those or will they stay?

Tldr; How small and precious could you be when using the iron chloride method?


Those lines are called traces.

they can be very, VERY thin, but that are rules to how thin they should be. For digital signals (low voltage, very low current) width isn't much of a factor, but for power signals it is.

Take a look at this "Trace Width Calculator": http://circuitcalculator.com/wordpress/?p=25/

About ferric chloride: it can give very precise results. From my experience, what determines how precise and how thin your traces can be, isn't the etching method, but the trasnfer method. Some transfer methods issue much more precise results than others. I've had good experience with toner transfer, with traces as thin as 8mil, although 99% of the time I keep them wider than 15mil just for safety.



Title: Re: first pcb try
Post by: swescrew on Apr 22, 2013, 06:25 pm
About ferric chloride: it can give very precise results. From my experience, what determines how precise and how thin your traces can be, isn't the etching method, but the trasnfer method. Some transfer methods issue much more precise results than others. I've had good experience with toner transfer, with traces as thin as 8mil, although 99% of the time I keep them wider than 15mil just for safety.

Thank you so much sir for your answer  :)

What do you mean with the "transfer method" and what is a "toner transfer" ?
Thank you again for your informative reply,
best regards!

Edit: Never mind I searched for it on google. But what other transfer methods are their?
Title: Re: first pcb try
Post by: AlxDroidDev on Apr 22, 2013, 07:07 pm

Edit: Never mind I searched for it on google. But what other transfer methods are their?


Ok! So by now you know that a transfer method is how you go from the PCB's CAD (computer aided design), from whatever software package you are using, to have it printed on a blank copper board, ready to be etched by whatever method.

Toner transfer is one amog several transfer methods. I like it because I have a good laser printer and it is one of the cheapest of them all. I usually use glossy magazine paper (I prefer to use some of my wife's magazines because they have very thick and glossy paper, which is better for this purpose). I've also resorted to transparencies. Whatever paper/media you use, the method is still: print with a laser printer, using the darkest settings, and then use a very hot clothing iron to transfer the printed image to a black copper board.

Another method is direct printing. Some people have adapted ink jet printers to print the PCB directly to a blank copper board. This is fast and issues excellent results.

Although there are several other methods, the best method - quality-wise - however, is photo-transfer. It takes the longest and is the most expensive, but it also gives you industrial-quality results, or even better. You can have extremely low tolerances with this method.

There are other methods, like special papers, which are simply a variation of the toner transfer methods, but which are more expensive.