HardLabs

4chord midi

sgreg·4chord-midi·hardware/ATmega328-TQFP32/4chord-midi.kicad_pcb

4chord midi PCB layout, top view — open source AVR/Arduino board by sgreg

About the 4chord midi PCB

4chord midi is an open source AVR/Arduino PCB design by sgreg, published on GitHub. It is a 2-layer board measuring 74.8 × 84.7 mm, with 60 components from 31 distinct parts.

Its main chip is the ATMEGA328P-A, from the AVR/Arduino family. Other key parts include the LD1117S33CTR and NOKIA_5110_LCD. By type, the board carries 18 resistors, 16 capacitors, 7 switches, 4 connectors, 4 diodes and 3 ICs.

It belongs with the audio and keyboards designs in this gallery.

From the project

The 4chord USB MIDI Keyboard

Note: All content was designed using KiCad 4. This should be updated to KiCad 5 eventually. Schematics are additionally provided in PDF and PCB layouts in Gerber format.

- Atmega328-TQFP32: - SMD version - 32pin TQFP ATmega328 - Nokia 5110 clip-in LCD

KiCad didn't have footprints for it, so I created one that is available in my kicad-libs repo, with more information available on its dedicated hackady.io project page.

Main components on the 4chord midi

ATMEGA328P-ALD1117S33CTRNOKIA_5110_LCD

4chord midi bill of materials (BOM)

60 components, 31 distinct parts — part numbers from the project's BOM.

QtyPartRefs
1
ATMEGA328P-A
IC1
1
LD1117S33CTR
U1
1
NOKIA_5110_LCD
Nokia_5110_LCD
U2
1
2N7002
Q1
1
12MHZ
12MHz
X1
1
USB_B
P1
1
Programmer
P2
1
UART
P3
1
UART Power
P4
1
LOGO
G1
1
LOGO
G2
1
qr
G11
1
4chordmidi
G12
1
craplab
G22
1
finland
G31
1
<
SW1
1
Select
SW2
1
>
SW3
1
I
SW4
1
V
SW5
Show 11 more
QtyPartRefs
1
vi
SW6
1
IV
SW7
4
LED
D1, D2, D3, D4
2
10U
10u
C1, C2
12
100N
100n
C3, C4, C5, C8, C9, C10, C11, C12 +4
2
27P
27p
C6, C7
2
68R
R1, R2
1
1K5
1k5
R3
2
1M
R4, R17
8
10K
10k
R5, R6, R7, R8, R9, R10, R11, R18
5
100
R12, R13, R14, R15, R16

4chord midi design files

The KiCad project lives in the sgreg/4chord-midi repository on GitHub; these links point at the commit this page was built from.

4chord midi: common questions

What microcontroller does the 4chord midi use?

The 4chord midi is built around the ATMEGA328P-A, from the AVR/Arduino family.

How big is the 4chord midi PCB?

The 4chord midi measures 74.8 × 84.7 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the 4chord midi?

60 components, from 31 distinct parts, with part numbers taken from the project's own BOM. The full bill of materials is listed on this page.

Where can I download the 4chord midi design files?

From the sgreg/4chord-midi repository on GitHub, which has the KiCad layout and the BOM; the links under Design files point to each one.

Can I use the 4chord midi design in my own project?

The repository has no license, so all rights stay with sgreg. Use it as a reference, and ask the author before reusing the design.

Can I test firmware for the 4chord midi without the hardware?

Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug AVR/Arduino firmware against it before you order a PCB.

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