Last night my ISP was having problems and I lost my network connection. When it returned, all my computers reconnected, except for my two Photons which had been online at the time. Now they’re both doing a pattern of alternating fast and slow green flashing.
Working on the first one, I put it into Listening Mode and ran the Patricle app. I clicked on “+” and it found the Photon. I selected my wi-fi network and it ran through all the steps (configuring credentials, connecting, etc.) ending with “Congrats! You’ve successfully set up your Photon!” I exited the app and then rebooted the Photon.
But now it’s right back to bllinking green. And if I re-run the Particle app, it shows the Photon as Offline. I tried connecting to a different wi-fi network with the same results. Unlike other threads I’ve seen here, this problem isn’t related to a firmware update. Any ideas?
UPDATE
Not five minutes after posting that, after flashing green for 12 hours both Photons suddenly connected to the net. It can’t be anything I did because I only tinkered with the first one. I didn’t do anything to the other one. Perhaps I’ve discovered a new way of resolving connectivity issues - just write about them in the forum.
It’s hard to say. After another 12 hours, all is still normal. It can’t be an issue with the Photons themselves since they both resolved at the same time. But my Internet connection had been up for 12 hours when that happened and all my other machines were connecting normally the whole time.
I checked my stats on OpenDNS and found that my LAN had generated about 60% more requests yesterday than normal, with an order of magnitude greater number of IPv6 requests, which is odd.
So I’m leaning to some sort of DNS lookup problem. I don’t really know how else to trace this after the fact. Next time I can try wiresharking the Photon to see if that shows anything interesting. Just out of curiosity, what domain is the Photon looking for when it phones home?
Photons attempt to resolve device.spark.io, and in system firmware 0.6.0 and later, they will only use the resolved DNS name. In prior versions, there was a hardcoded fallback.
Well I have the latest firmware, so I guess a DNS failure isn’t out of the question. One thing I did notice I forgot to mention, right after it did a cycle of fast green flashing -> slow green flashing, before it went back to fast flashing, I could swear I saw the briefest tiny blink of cyan, like 0.1 seconds worth, as if it connected but then instantly dropped out.