https://bues.ch/cgit/pbwake.git/
Pbwake is a small USB stick to prevent power banks from shutting off the outputs and falling into deep sleep mode.
Pbwake uses tiny load pulses to simulate a real load on the power bank outputs. The lengths of the load pulse active (high) and inactive (low) phases are pseudo random within configurable bounds.
Pbwake is in a low power state during the inactive (low) phases. Therefore it doesn't waste too much power and guarantees high battery life of the power bank.
Power banks this has been tested with are:
- Anker PowerCore 20100 model A1271.
- No-name power bank 2200 mAh / 11 Wh with integrated flashlight LED.
Pbwake supports the following microcontrollers:
- ATTiny-13
- ATTiny-25
- ATTiny-45
- ATTiny-85
- ATMega-328P
Schematics: schematics/pbwake-attiny/pbwake.pdf
The hardware may be built manually on a simple prototype board.
Board front side:
Board back side:
The release archives of pbwake contain prebuilt .hex files for all supported microcontrollers in the hex directory. These hex files can be flashed directly to the microcontroller with a any tool of your choice (e.g. Atmel Studio or avrdude).
The corresponding fuse settings can be found in the file fuses.txt in the same directory.
The firmware build needs the following tool chain:
- Unix-like operating system
- GNU make
- AVR GCC
- AVR Binutils
- avrdude
Run the following commands to build the firmware:
cd firmware
make DEV=t85Please specify the target microcontroller using the DEV variable as shown above.
Valid values are:
| Microcontroller | make option |
|---|---|
| ATTiny 13 | DEV=t13 |
| ATTiny 25 | DEV=t25 |
| ATTiny 45 | DEV=t45 |
| ATTiny 85 | DEV=t85 |
| ATMega 328P | DEV=m328p |
Additional build options that can be passed to make:
| make option | default | description |
|---|---|---|
| CONF_HIGH_MIN_MS | 4 | Minimum length of high-phase (in milliseconds). |
| CONF_HIGH_MAX_MS | 6 | Maximum length of high-phase (in milliseconds). |
| CONF_LOW_MIN_MS | 40000 | Minimum length of low-phase (in milliseconds). |
| CONF_LOW_MAX_MS | 55000 | Maximum length of low-phase (in milliseconds). |
Run the following commands to flash the firmware to the target microcontroller:
cd firmware
make DEV=t85 print_fuses
make DEV=t85 write_fuses
make DEV=t85 write_memOr alternatively use any other of the available AVR flashing tools to program the .hex file and fuses.
Copyright (c) 2020 Michael Buesch <m@bues.ch>
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.