This Arduino sketch pings external servers over the Internet to check if your Internet connection is up or down. If it's down, a relay attached to the Arduino reboots your router, cablemodem or any other CPE you're using, by cutting it's power supply for a second. Notice this is only useful for equipments that doesn't auto-reconnect to the Internet when they loose connection.
- Any Arduino-like capable board. Tested on Arduino Uno (official & clone) and Arduino Mega (clone).
- An Ethernet Shield using the W5100 chip, or any other compatible with the Ethernet library
- One relay, activated with LOW digital input
- Ethernet and ICMPPing libraries; PubSubClient optional for MQTT support (MQTT not implemented yet)
- Multiple external server definition
- False positive tolerance
- Highly customizable
- Complete debug over Serial
- Two LED debug (OK/FAIL system), can use a bi-color LED
- MQTT debug, web interface & SD card support (coming soon)
Arduino will pick a random server from the list of servers provided, but won't ping the same server twice in a row, avoiding false positives (when your Internet connection is UP but the server is down). If it can't ping the server, will add +1 to an "error" counter. When this counter reaches a certain ammount of errors (4 by default), CPE will reboot. This counter will be reset when CPE is rebooted, or after another ping is successful.
CPE Vcc or GND from power supply should be connected between Normally Closed and Common pins of the relay, so it will be ON by default, when relay is OFF. On the sketch, relay pin is LOW for relay ON, and HIGH for relay OFF. When Arduino reboots the CPE, will turn on the relay for a second and turn if off again, so will cut off power from CPE rebooting it. After rebooting the CPE, the system will wait for 2 minutes before resuming pings, giving enough time for CPE to reboot and reconnect to the Internet.
Some network equipment (routers, switches...) doesn't work well with the W5100 Ethernet Shield, not working at all, or making a bit longer to establish link with it. On this last case, when using static IP on the Arduino, false positives will happen, since Arduino will get a static IP but won't be connected yet to the LAN. Using DHCP doesn't show this problem, since it has to get an IP from the DHCP server before starting pings.