Weather station project requires reset for Ethernet shield to start

on my weather station project, i seem to have an issue where if the power fails, and comes back, it requires that i reset the board for the Ethernet shield to start up. i don't remember the brand or model Ethernet shield, only that it is off-brand, and i think W5200 chipset. i have ordered a new Arduino W5500 chipset Ethernet shield to see if it helps, but in case it doesn't solve the issue...

power supply is a PoE splitter from Adafruit that puts out a hair over 5Vdc, @ 2.5A.
code is here: WeatherStation/WeatherStation.ino at master · travis-farmer/WeatherStation · GitHub

really, i think it is the Ethernet shield, but if somebody else knows where the issue could be from... i am open to suggestion.
not a particularly great remote weather station if i have to go out and hit reset whenever the power fails. :wink: seems to work great otherwise.


forgot to mention, Arduino board is a Mega2560.


I had a Pi that did the same thing with Wifi: fine on power up as long as the house had had electricity for a while, but couldn't ever connect after a power cut. None of my other Pis had a problem and I eventually just swapped the SD card into a new Pi - problem solved.

It might be worth resetting the Arduino A few minutes after the power returns if you don't have ethernet working. An assembler jump to zero perhaps. Or if necessary, McGyver something to press hard reset. Just make sure it's a momentary press & release :grinning:

i will try the assembler jump, followed by the hard-reset idea, and see if it helps. Thanks!


Install an external watchdog, that will reset everything for you.

The reason for that is the Wiznet boots faster than your typical home router. By the time it starts to request IP addresses via DHCP, your home router is probably not done booting yet. You have to account for this. You can have Arduino reboot when it can't connect to the network (instead of an infinite while loop) and it will do that until the rest of your network is ready

the router is on battery backup, and standby generator, so it isn't waiting for the router to boot. it reports hardware not found, so i think it is the ethernet shield. i did manage to find a post on this forum, though i lost the reference to it, where older ethernet shields sometimes do not boot, without a reset for some reason. either way, i have already ordered a replacement NEW Arduino Ethernet 2 shield, so i will see if that improves it.

@wildbill the assembler jump didn't help. i will try the hardware reset if the new shield doesn't help.

if everything fails, i may just add a battery backup system... i may do that either way...


I found a way around this error in this article. I hope it helps you too.

the new Arduino Ethernet 2 shield made all the difference. now it self-starts when power is restored, and establishes connection over the network.

I thank you all for your assistance, and as before, and i will say again, i LOVE Arduino boards!


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