<> = Perfboard Design = In an effort not to limit my capabilities with the keyer's software, I wanted to make sure whatever prototype I eventually built could double as a development board. To that end, I implemented all optional components of the !SpiffChorder circuit (programming header, LEDs, pull-up resistors and screw terminals for all 8 chord keys and 3 modifier keys). I tried to keep the layout as compact as possible while still working on single-sided pad-per-hole perfboard, using entirely right-angle traces so as not to make stray contact with corners of square pads. It fits in a 17x21-hole grid including a ground bus all the way around the perimeter. Here's a top-down view showing the logical supply, ground and signal paths colored for easy identification, the front showing just silkscreen markings and jumpers, and one with the traces on the back (mirrored for easier visual reference). [[attachment:SpiffChorderPerfboardCircuit.png|{{attachment:SpiffChorderPerfboardCircuitThumb.png|SpiffChorder perfboard circuit}}]] [[attachment:SpiffChorderPerfboardLayoutFront.png|{{attachment:SpiffChorderPerfboardLayoutFrontThumb.png|SpiffChorder perfboard front}}]] [[attachment:SpiffChorderPerfboardLayoutBack.png|{{attachment:SpiffChorderPerfboardLayoutBackThumb.png|SpiffChorder perfboard back}}]] [[attachment:SpiffChorderPerfboardFront.jpg|{{attachment:SpiffChorderPerfboardFrontThumb.jpg|SpiffChorder perfboard front}}]] [[attachment:SpiffChorderPerfboardBack.jpg|{{attachment:SpiffChorderPerfboardBackThumb.jpg|SpiffChorder perfboard back}}]] I initially sketched the layout on graph paper and transferred it into [[https://live.gnome.org/Dia|Dia]] by hand. [[attachment:spiffchorder.dia|Here's the multi-layer original from which the above graphics were exported.]] Installing all those tiny traces without accidentally shorting any together was painfully time-consuming, so I recommend you use my [[../KeyerPCB|printed circuit board]] instead if you can. = Bill of Materials = This is a revised version of the !SpiffChorder Digikey bill of materials including all the parts I used for this board. If you're lazy like me you may just want to load [[https://ordering.digikey.com/registereduser/bombillofmaterials.aspx?path=1&exist=1&id=68483|the copy I've published on Digikey's site]], or if that's not working import [[attachment:SpiffChorderPerfboardDigikey.csv|the CSV I saved]]. ||'''index'''||'''quantity'''||'''part number'''||'''description'''||'''customer reference'''|| ||1||2||490-3709-ND||CAP CER 22PF 50V 5% RADIAL||C1-2|| ||2||2||399-4328-ND||CAP CER 0.1UF 100V 10% RADIAL||C3/5|| ||3||1||493-1767-ND||CAP ALUM 10UF 16V 20% RADIAL||C4|| ||4||1||609-2846-ND||CONN HEADER 6POS DUAL R/A PCB||CON1|| ||5||5||A98335-ND||TERM BLOCK 4POS SIDE ENT 2.54MM||CON2-4|| ||6||1||96018-ND||TOOL SCREWDRIVER SLOTTED 1.8MM||screwdriver for CON2-4|| ||7||2||1N5227BDICT-ND||DIODE ZENER 3.6V 500MW DO-35||D1-2|| ||8||1||ATMEGA168-20PU-ND||IC AVR MCU 16K 20MHZ 28DIP||IC1|| ||9||1||ED90054-ND||IC SOCKET 28PIN MS TIN/TIN .300||socket for IC1|| ||10||1||OD222JE-ND||RESISTOR 2.2K OHM .25W CARB COMP||R1|| ||11||1||OD472JE-ND||RESISTOR 4.7K OHM .25W CARB COMP||R2|| ||12||2||OD820JE-ND||RESISTOR 82 OHM .25W CARB COMP||R3-4|| ||13||3||OD102JE-ND||RESISTOR 1.0K OHM .25W CARB COMP||R5-7|| ||14||1||CSC10KW-ND||RES ARRAY 10K OHM 8 RES 9-SIP||R8-15|| ||15||3||OD103JE-ND||RESISTOR 10K OHM .25W CARB COMP||R16-18|| ||16||1||XC1380-ND||CRYSTAL 12.000 MHZ 18PF CYL||X1|| ||17||7||CH196-ND||SWITCH PUSH SPST-NO 0.01A 12V||key switches|| ||18||1||67-1062-ND||LED 3MM 5V SHORT LENS GREEN DIFF||near thumb lamp|| ||19||1||67-1080-ND||LED 3MM 5V SHORT LENS YEL DIFF||center thumb lamp|| ||20||1||67-1068-ND||LED 3MM 5V SHORT LENS RED DIFF||far thumb lamp|| ||21||1||V2025-ND||BOARD 2-SIDE PPH 2.0X3.0||project board|| = Connector Details = The perfboard design assumes a keyed through-hole 2x3 right-angle shrouded header of the correct size for the USBtinyISP AVR Programmer (CON1), and 5x 0.1" pitch through-hole 4-line right-angle screw terminals (these take a 1.8mm jeweler's screwdriver) to connect leads for all the switches, LEDs and USB (CON2-4). {{attachment:RightAngleShroudedHeader.jpg|right-angle shrouded header}} {{attachment:RightAngleScrewTerminals.jpg|right-angle screw terminals}} = Resistor Details = You'll notice this layout uses an 8-resistor array instead of Greg Priest-Dorman's 9x (to save on space). I also show couple of 3-resistor arrays (R5-7, R16-18)... Digikey has no such beast, but I bussed individual resistors mounted vertically by soldering the common leads together above the board (only passing one of the three through the board). ---- [[../|back to The Man-Machine...]]