HardLabs

Grinder timer

Clewsy·grinder_timer·hardware/pcb/grinder_timer.kicad_pcb

Grinder timer PCB layout, top view — open source AVR/Arduino board by Clewsy

About the Grinder timer PCB

Grinder timer is an open source AVR/Arduino PCB design by Clewsy, published on GitHub under the MIT license. It is a 2-layer board measuring 75 × 120 mm, with 31 components from 28 distinct parts.

Its main chip is the ATmega328PB-AU, from the AVR/Arduino family. Other key parts include the 5V. By type, the board carries 6 switches, 6 capacitors, 5 connectors, 5 resistors, 2 ICs and 1 transistor.

It belongs with the displays & leds designs in this gallery.

From the project

A programmable timer for a coffee grinder. Mirrored from GitLab.

Modelled and printed a bezel for the OLED to tidy-up the enclosure. Modelled in [freecad][linkwebfreecad], printed on a [Prusa CORE One+][linkwebprusa]. CAD files and photo [here][linkrepobezel].

More information can be found at my [project page][linkclewsgrindertimerrev2].

- Hardware: - [X] Pull-ups on I2C SDA and CLK lines. - [X] Drive relay with a transistor instead of direct from IO. - [X] Add flyback diode protection to relay coil. - [X] Smaller transformer. - [X] Smaller relay. - [X] Switch to SMD where possible. - [X] Two-sided PCB (have it fabricated instead of etching). - [X]…

Main components on the Grinder timer

ATmega328PB-AU5V

Grinder timer bill of materials (BOM)

31 components, 28 distinct parts.

QtyPartRefs
1
ATmega328PB-AU
U1
1
5V
U2
1
NPN
Q1
1
32.768kHz
Y1
1
AVR-ISP-6
J1
1
SERIAL
J2
1
MOTOR
P1
1
NEUTRAL
P2
1
ACTIVE
P3
1
D_Bridge
B1
1
Relay
K1
1
RESET
S0
1
UP
S1
1
DOWN
S2
1
LEFT
S3
1
RIGHT
S4
1
GRIND
S5
1
1P1S
T1
1
OLED
O1
1
4148
D1
Show 8 more
QtyPartRefs
1
470uF
C1
2
0.1uF
C2, C3
1
10uF
C4
1
7pF
C5
1
17pF
C6
2
1.8k
R1, R2
2
10k
R3, R5
1
150
R4

Grinder timer design files

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

Grinder timer: common questions

What microcontroller does the Grinder timer use?

The Grinder timer is built around the ATmega328PB-AU, from the AVR/Arduino family.

How big is the Grinder timer PCB?

The Grinder timer measures 75 × 120 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the Grinder timer?

31 components, from 28 distinct parts. The full bill of materials is listed on this page.

Where can I download the Grinder timer design files?

From the Clewsy/grinder_timer repository on GitHub, which has the KiCad layout; the links under Design files point to each one.

Can I use the Grinder timer design in my own project?

Yes, under the terms of its MIT license, which Clewsy chose for the repository.

Can I test firmware for the Grinder timer 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.

Similar boards