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2 layers439 × 141.6 mmAek2 usb, the printed circuit board in 3D

drop-in replacement pcb for the AEK II

Size
439 × 141.6 mm
Copper layers
2
Thickness
1.6 mm
Parts
241
Nets
149
Pads
522
Tracks, vias
1,642, 0
Pours
702
Routed
Yes
KiCad
KiCad 5 (file 20171130)
Created
19 Jul 2020
Updated
12 Nov 2021

Overview

Aek2 usb is an open-source printed circuit board by str-dst, from the str-dst/aek2_usb repository on GitHub. It is a 2-layer board of 439 × 141.6 mm with 241 parts on 149 nets, routed with 1,642 tracks and 0 vias.

It is built around the ATMEGA32A-PU. Its parts include 110 diodes, 7 resistors, 5 capacitors, 2 connectors and 1 IC. It belongs with the AVR (ATmega, ATtiny) boards of this library.

Main components

1

README

README.md

AEK II USB

CC BY-NC-SA 4.0 kofibadge

This project is completed and will not get updated anymore.

QMK compatible drop-in replacement PCB for the Apple Extended Keyboard II

The PCB is built entirely with THT parts to keep a somewhat "vintage" look to it and it uses the fullsize 40-pin DIP package ATmega32A. The controller is placed in the exact same location as the one on the original PCB.

drawing drawing

Partslist

Most of the parts in this list are just examples and they can be replaced with any component with the same specs.
They don't have to be from any specific manufacturer or brand to work on this board.

The USB breakout PCB/Daughterboard is NOT included in this repo. You will have to find one yourself.
Pretty much any kind of breakout board that has usable VCC, GND, D+ and D- pins should work for this.
Example: https://www.adafruit.com/product/1764

CountPartDesignatorOctopart URL
1ATmega32A 40 pin DIP (32L works too)U1Atmega32a-pu
140 pin DIP socket (optional but highly recommended)U1TE Connectivity 1-2199299-5
12x3 pin header 2.54mm (for ISP flashing)AVR1Würth 61200621721
1JST PH 2mm 4pin connector + cableJ1, J2JST S4B-PH-K-S
1USB breakout PCBAdafruit 1833
1500 mA polyfuseF1Bourns MF-R050
26mm momentary push buttonsRESET1, BOOT1TE Connectivity 1825910-6
116 MHz quarz crystalXTAL1Raltron AS-16.000-18
14.7 uF electrolytic capacitorC1Panasonic ECA-1HM4R7I
2100 nF ceramic disk capacitorC2, C3Kemet C315C104M5U5TA
222 pF ceramic disk capacitorC4, C5Kemet C317C220J1G5TA
110 kΩ resistorR4Multicomp MF25 10k
268 Ω resistorR2, R3Multicomp MF25 68R
41.5 kΩ resistorR1, R5, R6, R7Multicomp MF25 1k5
35mm LED (for the lock indicators)LED1, LED2, LED3Vishay TLHG5400
23.6 V zener diode (DO-35 BZX55C3V6)D1, D2ON Semiconductor BZX85C3V6
105universal switching diode (DO-35 1N4148)D3-D107ON Semiconductor 1N4148
Some pictures of the first finished PCB


This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

CC BY-NC-SA 4.0

Parts

241
QtyValueFootprintReferences
105D_Smallcustom_parts:D_DO-35_SOD27_P7.62mm_HorizontalD10, D11, D12, D13, D14, D15, D16, D17, D100, D101, D102, D103, D104, D105, D106, D107 +89
90MX-NoLEDAlps_Only:ALPS-1UMX1, MX2, MX10, MX11, MX12, MX13, MX14, MX15, MX16, MX17, MX18, MX19, MX101, MX103, MX104, MX105 +74
6MX-NoLEDAlps_Only:ALPS-1.5UMX27, MX40, MX67, MX69, MX75, MX77
41.5KResistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_HorizontalR1, R5, R6, R7
3LEDLED_THT:LED_D5.0mmLED1, LED2, LED3
3MX-NoLEDAlps_Only:ALPS-2UMX26, MX100, MX102
20.1uCapacitor_THT:C_Disc_D3.0mm_W2.0mm_P2.50mmC2, C3
222pCapacitor_THT:C_Disc_D6.0mm_W2.5mm_P5.00mmC4, C5
23.6VDiode_THT:D_DO-35_SOD27_P7.62mm_HorizontalD1, D2
268RResistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_HorizontalR2, R3
2Conn_01x04Connector_JST:JST_PH_S4B-PH-K_1x04_P2.00mm_HorizontalJ1, J2
2MX-NoLEDAlps_Only:ALPS-2.25UMX54, MX55
2MX-NoLEDAlps_Only:ALPS-1.25UMX68, MX76
2MountingHole_Padcustom_parts:screw-holeH1, H2
110kResistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_HorizontalR4
14.7uCapacitor_THT:CP_Radial_D5.0mm_P2.50mmC1
1500mAFuse:Fuse_Littelfuse_395SeriesF1
1ATmega32A-PUPackage_DIP:DIP-40_W15.24mm_SocketU1
1AVR-ISP-6Connector_PinHeader_2.54mm:PinHeader_2x03_P2.54mm_HorizontalAVR1
1BootButton_Switch_THT:SW_PUSH_6mmBoot1
1CrystalCrystal:Crystal_HC49-4H_VerticalXTAL1
1LOGOcustom_parts:alps_logoG***
1LOGOcustom_parts:oshwG***
1LOGOcustom_parts:qmkG***
1LOGOcustom_parts:pear_x_elmo_copperG***
1MX-NoLEDAlps_Only:ALPS-2.75UMX66
1MX-NoLEDAlps_Only:ALPS-1.75UMX41
1ResetButton_Switch_THT:SW_PUSH_6mmReset1

Questions

How big is the Aek2 usb PCB?

It measures 439 × 141.6 mm and has 2 copper layers, 1.6 mm thick.

What parts does the Aek2 usb use?

241 parts, built around the ATMEGA32A-PU. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.

Where can I download the Aek2 usb KiCad files?

From the str-dst/aek2_usb repository on GitHub, at the commit this page was made from: the board is aek2_usb.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.

Can I use the Aek2 usb design in my own project?

Its repository states no licence, so its author keeps all rights: ask str-dst before reusing the design.

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