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Product description: PiWatcher - Raspberry Pi Watchdog
The PiWatcher is a small board that helps to completely shut down or restart the Raspberry Pi to save power, for example. The board can also be programmed to shut down or automatically restart the Raspberry Pi every few minutes or every few hours. PiWatcher is a programmable Watchdog chip for the Raspberry Pi. The board has a miniature clock switch that allows for manual control. It is also equipped with anLED. PiWatcher is powered by5 volts through themicroUSBsocket.
What is a Watchdog?
Awatchdogis a device or a program, or usually anelectroniccircuit, thatdetects a malfunction of the systemand tries to fix it without human intervention. It prevents more serious failures. It is installed in systems which often work without human operation, and their uninterrupted operation is very important. It allows to eliminate the negative effects of unforeseen actions.
Mounting PiWatcher to Raspberry Pi
The PiWatcher board is mounted on the first six GPIO pins of the Raspberry. It needs to be connected to themicroUSBpower supply. Based on instructions received via I2C, the PiWatcher can:
- Shut down (or restart) the Raspberry Pi if it stops responding for more than "X" seconds
- Shut down and restart the Raspberry Pi after a few seconds, minutes or hours, e.g. for repetitive tasks
The kit does not include theRaspberry Piminicomputer or the power cord.
Power management solution for Raspberry Pi
PiWatcher is designed to solve 2 power management problems on Raspberry Pi.
- If you shut down the Raspberry Pi via software, such as by issuing a shutdown or stop command, the Raspberry stops working but does not shut down completely. Instead, it goes into an idle state where it continues to drawbetween 30 mA and 50 mA, sometimes more, depending on the peripherals connected. A minicomputer consuming electricity all the time may become a problem in battery-powered systems. That's why it's a good idea then to use the PiWatcher device, which can be programmed to completely cut off power to the Raspberry Pi after a certain delay of inactivity.
- The second power management issue relates to the ability to restore the minicomputer after situations where the Raspberry Pi crashes. In theory, this shouldn't happen, but a Raspberry Pi that has been running for too long can "crash" due to software or hardware failures, for example, or even environmental factors such as high ambient temperatures. In some cases, the best approach to solving this problem is to simply turn the Raspberry Pi off and on again, allowing the application to continue and/or send an alert.
In addition, the PiWatcher can be programmed to operate with some delay,from a few seconds to about 36 hours, before restarting the minicomputer after being turned off. The PiWatcher has anLED light. When the Raspberry Pi is on, the LED lights up continuously, and when it is off, the LED blinks slowly.
The PiWatcher is equipped with a tact switch. When the Raspberry Pi minicomputer is running:
- A long press (for 5 seconds) on the button will completely turn off the Raspberry Pi
- A short press (for half a second) of the button sends a software signal that can be used for user-defined purposes.
Once the Raspberry Pi has shut down, a short press of the button will restart the Raspberry.
Pinouts on the PiWatcher board
Contents of kit
- PiWatcher - Raspberry Pi Watchdog
- Female strip 2 x 3 for soldering
Elements included in the kit.
PiWatcher is compatible with:
- Raspberry Pi ZeroandRaspberry Pi Zero W
- RaspberryPi 4(Note:not compatible with official USB C power supply)
- Raspberry Pi 3B
- Raspberry Pi 2B
- Raspberry Pi model B, with additional I2C configuration
This product is not compatible with the official USB C power supply when using Raspberry Pi 4.
How to use PiWatcher
PiWatcher is fully controlled using a command line tool called PiWatcher, which is very easy to use. For more information, including instructions on how to download the software, please see the full documentation in the useful links.
Warning:PiWatcher may not work properly if the Raspberry Pi minicomputer is connected to some power-hungry peripherals, such as an SSD hard drive, or with peripherals that have a separate power supply