HardLabs

Hrem

bazhenov·hrem·hardware/hrem.kicad_pcb

Hrem PCB layout, top view — open source AVR/Arduino board by bazhenov

About the Hrem PCB

Hrem is an open source AVR/Arduino PCB design by bazhenov, published on GitHub under the MIT license. It is a 2-layer board measuring 80 × 44.5 mm, with 25 components from 20 distinct parts.

Its main chip is the ATtiny85, from the AVR/Arduino family. Other key parts include the HT7733A and 74LVC1G125. By type, the board carries 6 resistors, 5 capacitors, 4 ICs, 2 connectors, 2 diodes and 1 transistor.

From the project

Hardware design (PCB) and firmware for the simple door latch reminder

This project contains firware code and KiCad schematics/PCB files for simple door latch reminder.

Me and my wife forget to close our flat entrance door from time to time. What will you do about that? :)

This project is simple hardware solution to remind us about open door. It's not the simplest nor most elegant solution, but more like excuse for practicing skills in embedded software development and electrical engineering.

Hrem, from the project README
From the project README

Main components on the Hrem

HT7733AATtiny8574LVC1G125

Hrem bill of materials (BOM)

25 components, 20 distinct parts.

QtyPartRefs
1
HT7733A
U1
1
ATtiny85
U2
2
74LVC1G125
U3, U4
1
MMBT4401-7-F
Q1
1
AVR-ISP
J1
1
Hall_Conn
J2
1
1xAAA
BT1
1
Buzzer
BZ1
1
SW_Push_Dual
SW1
1
TestPoint_Flag
TP1
1
SS14-E3/61T
D1
1
LED
D2
1
100uH
L1
1
47uF
C1
1
22uF
C2
3
100nF
C3, C4, C5
1
10K
R1
1
680R
R2
2
100R
R3, R4
2
0R
R5, R6

Hrem design files

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

Hrem: common questions

What microcontroller does the Hrem use?

The Hrem is built around the ATtiny85, from the AVR/Arduino family.

How big is the Hrem PCB?

The Hrem measures 80 × 44.5 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the Hrem?

25 components, from 20 distinct parts. The full bill of materials is listed on this page.

Where can I download the Hrem design files?

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

Can I use the Hrem design in my own project?

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

Can I test firmware for the Hrem 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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