WatchDog Timers – Building Reliable Systems – New Instructable –
SwitchDoc Labs is pleased to announce a new Instructable for using WatchDog Timers in Raspberry Pi and Arduino based 
projects. It ends with a discussion of external watchdog timers like the SwitchDoc Labs Dual WatchDog Timer.
What is in this Instructable?
Step 1 – Introduction to WatchDog Timers
Step 2 – How to Set Up the Raspberry Pi Internal WatchDog Timer
Step 3 – How to Set Up the Arduino Internal WatchDog Timer
Step 4 – Internal Versus External WatchDog Timers / Issues with Internal Timers
Step 5 – Adding an External WatchDog Timer to your Project
Step 6 – Suggestions for Educators and Conclusion
In this Instructable you will learn how:
- What are WatchDog Timers and Why they are Cool
- How To use the Raspberry Pi Internal Watchdog Timer
- How to use the Arduino Internal WatchDog Timer
- Compare and Contrast Internal Versus External WatchDog Timers
- How to use an External WatchDog Timer
- Suggestions for Student Experiments with WatchDog Timers
What is a WatchDog Timer?
In small computers, you give your device the chance to recover from faults by using what is called a WatchDog Timer (WDT). A WDT is an electronic timer that is used to detect and recover from computer malfunctions. If the computer fails to reset the timer (also called “patting the dog”) on the WDT before the WDT timer expires, the WDT signal is used to initiate either corrective actions or simply to reboot the computer.
The SwitchDoc Labs Dual WatchDog Timer is designed to make small computer such as the Arduino and Raspberry Pi more reliable by detecting and recovering from computer or software malfunctions. It has two WatchDog Timers that can be used independently or together to reset non-responsive computers. It directly can drive the Arduino Reset line, the Raspberry Pi B/B+ reset line or a to a relay to reset a Raspberry Pi.
