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== PCB == <<TableOfContents>>
= Printed Circuit Board Layout =
I used [[http://fritzing.org/|Fritzing]] to lay out a two-layer !SpiffChorder development board and submitted an order for the prototype to [[http://fab.fritzing.org/|Fritzing Fab]]. The fabrication cost for one unit, including international shipping to the USA, was roughly US$40. I'll post pictures once it arrives in a couple weeks and I have a chance to run tests, but here are some preliminary details:
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The printed circuit version is in progress using [[http://fritzing.org/|Fritzing]], and an order has been placed to [[http://fab.fritzing.org/|Fritzing Fab]] for a prototype to QA. I'll post pictures once it arrives in a couple weeks, but here are some tidbits to tantalize:
 * [[attachment:SpiffChorder.fzz|Fritzing file]]
 * [[attachment:SpiffChorderEtchable.pdf|combined etchable PDF]]
 * [[attachment:SpiffChorderGerber.zip|compressed ZIP archive of Gerber files]]
 * [[attachment:SpiffChorder.fzz|a Fritzing FZZ file containing the PCB layout]]
 * [[attachment:SpiffChorderSchematic.pdf|Fritzing's schematic view (printed to PDF at 450x315mm with no margins)]]
 * [[attachment:SpiffChorderEtchable.pdf|an etchable PDF export from Fritzing (combined using pdfunite from poppler-utils)]]
 * [[attachment:SpiffChorderGerber.zip|a ZIP archive of the Gerber export files for the prototype (sent to me by Fritzing Fab)]]

= Bill of Materials =
So far I'm using the same BoM from [[ManMachine/KeyerPerfboard#Bill of Materials|the perfboard design]], but I'll probably switch up CON1 with Digikey part 609-2845-ND (vertical rather than right-angle) so as not to block the lower-left mounting hole.

= Paper Placement Test =
Here's a paper test using a 1:1 scale printout of the silkscreen and solder mask together:

[[attachment:SpiffChorderPaperTest.jpg|{{attachment:SpiffChorderPaperTestThumb.jpg|SpiffChorder paper test}}]]

= Connector Detail =
The 0.1" pitch right-angle screw terminal blocks I used are just slightly longer than 0.4" each. So as to be able to fit the four for CON3-4 directly adjacent to one another, I lightly sanded the facing sides until they fit snugly but evenly in a piece of perfboard. In an effort to make it easier to solder these evenly on the board, I attached their sides together with a tiny dab of quick-setting adhesive gel (being careful not to get it into the terminals themselves):

{{attachment:ScrewTerminalSanding.jpg|screw terminal sanding}}
{{attachment:ScrewTerminalsGlued.jpg|screw terminals glued}}

= Condensed Board =
For implementation in tighter spaces, I plan to design a stripped-down board omitting CON1, removing lines for M1-3 and UC from CON3 and the associated R15-18, using an 8-pin array (Digikey part MSP10KH-ND) for R8-14, reordering the remaining lines on CON3 to support more direct paths through the PCB, and replacing the GND line from CON4 with VCC like I did on the perfboard layout (since CON3 exposes GND anyway). I may also go with lower-profile parts for C4 and X1 so that skipping the socket for IC1 and the screw terminals for CON2-4 allow the assembly to be about half as thick.

= ATmega32u4 =
Once I get more familiarity with AVR development, I'd like to roll up my sleeves and try my hand at implementing a !SpiffChorder clone on Adafruit's [[http://www.adafruit.com/products/296|Atmega32u4 Breakout Board]].
----
[[ManMachine|back to The Man-Machine...]]

Printed Circuit Board Layout

I used Fritzing to lay out a two-layer SpiffChorder development board and submitted an order for the prototype to Fritzing Fab. The fabrication cost for one unit, including international shipping to the USA, was roughly US$40. I'll post pictures once it arrives in a couple weeks and I have a chance to run tests, but here are some preliminary details:

Bill of Materials

So far I'm using the same BoM from the perfboard design, but I'll probably switch up CON1 with Digikey part 609-2845-ND (vertical rather than right-angle) so as not to block the lower-left mounting hole.

Paper Placement Test

Here's a paper test using a 1:1 scale printout of the silkscreen and solder mask together:

SpiffChorder paper test

Connector Detail

The 0.1" pitch right-angle screw terminal blocks I used are just slightly longer than 0.4" each. So as to be able to fit the four for CON3-4 directly adjacent to one another, I lightly sanded the facing sides until they fit snugly but evenly in a piece of perfboard. In an effort to make it easier to solder these evenly on the board, I attached their sides together with a tiny dab of quick-setting adhesive gel (being careful not to get it into the terminals themselves):

screw terminal sanding screw terminals glued

Condensed Board

For implementation in tighter spaces, I plan to design a stripped-down board omitting CON1, removing lines for M1-3 and UC from CON3 and the associated R15-18, using an 8-pin array (Digikey part MSP10KH-ND) for R8-14, reordering the remaining lines on CON3 to support more direct paths through the PCB, and replacing the GND line from CON4 with VCC like I did on the perfboard layout (since CON3 exposes GND anyway). I may also go with lower-profile parts for C4 and X1 so that skipping the socket for IC1 and the screw terminals for CON2-4 allow the assembly to be about half as thick.

ATmega32u4

Once I get more familiarity with AVR development, I'd like to roll up my sleeves and try my hand at implementing a SpiffChorder clone on Adafruit's Atmega32u4 Breakout Board.


back to The Man-Machine...

CCL: ManMachine/KeyerPCB (last edited 2012-07-02 21:40:29 by fungi)

CC0 To the extent possible under law, the creator of this work has waived all copyright and related or neighboring rights to it.