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Topic: DIY LCD Shield (Read 2730 times) previous topic - next topic

liudr

I have not done any etching yet. My workshop is just my entire desk top plus a cabinet. I don't like chemicals either. If you have eagle PCB questions, I can help. I've done over a dozen boards with eagle and they all work :)

inboxjason

I'll try and dive into Eagle this weekend, one thing I found making that shield was that there is o decent stripboard layout software.
Do you send your Eagle files off to be professionally made? How do you know that they'll work? Can Eagle simulate the curcuit?
Sorry for all the questions!

liudr

I check and recheck and let my wife press the submit button  :smiley-sweat:

I don't think eagle can simulate the circuit but I get help from the forum when I have problem or want someone help me check again. sparkfun has quite a few eagle tutorials and I started from there. To order boards, you can go to batchpcb.com or dorkbot pdx. It takes 3-3.5 weeks for me but it's worth the waiting.

inboxjason

I've had a little go at Eagle, and it is intuitive although a steep learning curve!
Heres the schematic for the lcd shield, it looks very messy to me - any suggestions?
I live in the UK so not too sure what BatchPCBs shipping policy is. Don't want to get stung with customs charges on top of shipping.

floresta

#19
May 13, 2011, 07:05 pm Last Edit: May 13, 2011, 07:18 pm by floresta Reason: 1
Quote
any suggestions?
I don't see any provisions for a current limiting resistor for the LCD backlight.  You might also want to consider provisions for software control of the backlight, either simple on/off or possibly PWM.

Keep in mind that you do not have to use any specific Arduino pins for your LCD.  You might want to investigate which pins are required for any other devices that you may wish to use with your LCD (TWI, PWM, External Interrupts, etc.) and choose different pins for your LCD.  If none of this is a consideration then you may wish to choose pins that make the pc board layout simpler.

By the way this is not really a schematic diagram, it more closely resembles a wiring diagram.  A true schematic diagram is designed to clearly show the signal flow, usually left to right, without regard to the actual physical pin locations on the individual devices.  A wiring diagram is designed with a physical pin arrangement similar to that of the actual devices and is more appropriate for pc board design (which is why Eagle uses this setup).


Don

brucethehoon

It's worth noting that without a current limiting resistor for your lcd backlight, there is a 90% chance that it will have a much shorter life.  There are a very few LCDs that use internal resistors, but I've only seen ONE.   

Some places to start with PCB etching and Arduino:

Here's a complete Eagle file with an Arduino shield footprint;
http://macetech.com/blog/node/92

Here's another, but all proto'd out:
http://www.arduino.cc/playground/Tutorials/Protoshield

I personally use the photo etching process:
http://www.youtube.com/watch?v=tWnfnt2rNO0

Other people swear by the toner transfer method:
http://www.youtube.com/watch?v=wKEe3otWstM

I get my photo boards here:
http://www.mdfly.com/index.php?main_page=product_info&cPath=65_66&products_id=721
(note: that's a pretty big board)

I will say that I've been able to get some pretty absurdly thin traces out of the photo method.    I made a board about a month ago that had 15 TSSOP-16 packages on it and it worked like a charm first time.   I know you can do that with toner - just saying I've been having good results.

The chemicals are dodgy.   Mind the warnings.   The ferric chloride DOES stain (as my old stainless{HA!} steel sink will attest).  The photo developer WILL give you a second head ala Zaphod Beeblebrox.  NO...  actually it just gives you death if ingested.

Wear a mask and if you can't do it in a well ventilated area: don't do it.

Be safe out there boys and girls!






liudr

RE the schematic, I'm pretty sure Vss is gnd and Vdd is 5V. You Swapped then. :D

inboxjason

@ Liudr - I'm an idiot, I did swap them. I'll get this right eventually!

@Brucethehoon - Thank you for the tutorials, this looks like the route I'll eventually be going down. I've got to get my head around Eagle first...

@Floresta - It seems obvious to swap the pins on the shield to make it neater, but this didn't occurr to me - I was too busy trying to get it all layed out correctly! What you're saying makes sense. Like the suggestion of software controlled backlight - would a PWM pin allow fades?

Think yet another redo is needed. I'm learning a lot on this thread, thanks everyone!

liudr

http://arduino.cc/forum/index.php/board,22.0.html

If you want to find out where to send your design for prototyping, just post here. Lots of people on the forum are in UK. They'll give you some pointers.

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