HardLabs

Metro

maxotar·metro·electrical/metro.kicad_pcb

Metro PCB layout, top view — open source AVR/Arduino board by maxotar

About the Metro PCB

Metro is an open source AVR/Arduino PCB design by maxotar, published on GitHub. It is a 4-layer board measuring 28 × 30 mm, with 29 components from 12 distinct parts.

Its main chip is the ATTINY1616-MN, from the AVR/Arduino family. Other key parts include the MCP73831T-2ACI/OT and DRV2605LDGS. By type, the board carries 9 resistors, 7 diodes, 7 capacitors, 3 ICs and 3 switches.

It belongs with the power & battery designs in this gallery.

From the project

A compact wearable metronome device that provides haptic feedback for keeping time. Perfect for musicians, dancers, and other performers who need portable tempo guidance.

A compact wearable metronome device that provides haptic feedback for keeping time. Perfect for musicians, dancers, and other performers who need portable tempo guidance.

- Project Name: Metro - Type: Wearable Device - Primary Function: Vibrating Metronome - Target MCU: ATtiny1616 - CPU Frequency: 4 MHz - Battery: 302025 LiPo - Charging: Smart ring magnetic pogo pin connector

Main components on the Metro

ATTINY1616-MNMCP73831T-2ACI/OTDRV2605LDGS

Metro bill of materials (BOM)

29 components, 12 distinct parts — part numbers from the project's BOM.

QtyPartRefs
1
ATTINY1616-MN
U1
1
MCP73831T-2ACI/OT
U2
1
DRV2605LDGS
U3
3
EVQ-P7C01P
S1, S2, S3
6
C125107
Red
D1, D2, D3, D4, D5, D6
1
D_Schottky
D7
3
1μF
C1, C4, C7
1
100NF
100nF
C2
3
10μF
C3, C5, C6
6
2K2
2k2
R1, R2, R3, R4, R5, R9
2
4K7
4k7
R6, R7
1
33K
33k
R8

Metro design files

The KiCad project lives in the maxotar/metro repository on GitHub; these links point at the commit this page was built from.

Metro: common questions

What microcontroller does the Metro use?

The Metro is built around the ATTINY1616-MN, from the AVR/Arduino family.

How big is the Metro PCB?

The Metro measures 28 × 30 mm, has 4 copper layers and is 1.0412 mm thick.

How many components are on the Metro?

29 components, from 12 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 Metro design files?

From the maxotar/metro repository on GitHub, which has the KiCad layout, the schematic and the BOM; the links under Design files point to each one.

Can I use the Metro design in my own project?

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

Can I test firmware for the Metro 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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