Photon flashing Green

Delivered a beta version of a product that I am developing to a stakeholder this week.

  • In the lab, the Photon worked seamlessly and had been running over 500 hours with no hard errors.
  • At the stakeholder’s house, I was able to get onto the Photon with a phone using photonsetup.html and entered the wifi credentials (i.e. ssid and pw). ssid and pw were correct - they were verified many times over.
  • When the Photon reboots, it flashes green and can not get onto the wifi network.
  • Erased the stored wifi settings and no help there
  • Was able to add other devices (phones and tablets) to the wifi network without error so I doubt DHCP nor restricted addresses are the culprits
  • Stakeholder is using a Comcast/XFINITY Arris modem
  • Cannot go monkeying about with the modem settings (and should not) since the Photon should be rather plug-n-play

==> Any ideas of the next steps to follow? Does not look good if I have to spend many hours trying to debug the problem at his house or having to change modem configurations

==> Has anyone else had issues trying to get a Photon onto a Comcast modem?

==> Rather embarrassing and lousy first impression

Is it using WEP encryption? If so, there’s a special procedure that needs to be followed, you can’t just enter the text or hex WEP key. It’s described here:


I have connected quite a few Photons to my Xfinity/Arris box (TG1682G) with no issues. I’ve never seen what you’re experiencing here in my labooooratory. I’ve used all of the various ways to provision them – html page, serial, mobile device.

One thing to check is the Arrix box’s firewall setting. The Photon uses port 5683 for outbound CoAP communications, and I note that the Maximum firewall setting does not allow that outbound port. (I have to admit that I have the firewall set to “Minumum”, and rely on the firewalls on my laptops.) I know it’s not desirable to have to modify firewall settings (the Arrix box is shockingly absent of granular control over inbound/outbound ports, unless I’m missing something), but 5683 is a bit unusual and that’s probably why the max setting blocks it.



For a presentation it may always be good to have a known good WiFi AP with you (e.g. mobile hotspot or phone tether) as a fallback.
Just imagine the AP owner hasn’t got a guest network and won’t want to share his WiFi private credentials or in corporate environment would need to go through several instances to get the network opened for “unknown” devices.

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