WiFi Flashing Green every 21 days or so

My cores seem to go south with flashing green every 21 days or so. I typically don’t see this happen but I’m running long term tests and it’s happened 3 times. Rebooting the core does not correct the problem. It happens around the same time on all of my cores.

Rebooting the WiFi access point corrects the problem. After a AP reboot the cores recover on their own and resume normal operation.

Does anyone have any ideas as to what I should look for?

@mtnscott, sounds like an AP side issue and not a Core DHCP lease issue cause rebooting the Cores does not fix it. The Core will flash green until it gets an IP (I believe) so for the AP not to lease an IP it is either:
a) The AP is relaying the DHCP request and the AP’s own lease with the router has expired (explaining why an AP reboot fixes things) or,
b) The AP IP lease to the Core has expired and for some reason it is not renewing it, even after you reboot the Core.

Any thoughts? :smile:

My DHCP Lease time is set to 1440 or 24 hours.

What’s strange is that the core has an IP already. It’s been running continuously for 21 days. Hmmm… It smells like a core issue, as none of the other computers / iPhones / DirectTV / iPads / Macs / Windows PC’s … have any issue with the AP.

I wonder if the core has a limit to the number of IP renews? I can try reducing my DHCP lease time to say 1 hour and see if they go green after 21ish hours… Not sure what other settings could affect this. My AP is a Cisco (LinkSys) EA4500. @bko - any ideas?

@mtnscott, so the Core goes “offline” after 21 days even though it is not powered off at any time? However, if it is a Core issue, why does it not grab a new lease when you reboot it? Instead, you have to reboot the AP! I am trying to figure out the relationship.

Hi @mtnscott

When the core is flashing green and can’t connect, are the other devices still connected on 2.4GHz? One way to make sure is to set the 5GHz SSID to be different from the 2.4GHz SSID.


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Excellent question! I will change the SSID for the 5GHz band and get back with you (in 21 days :slight_smile: )

What’s really strange is that the first time this happened I rebooted a core, when that did not work I reflashed the core, then after that did not work I reset the core to factory defaults - set the WiFi creds and still it did not work. So I took a look at the other cores and realized all of them were having the same problem (flashing green) I rebooted the AP and they all came back to life!!

They can sit in the bad state for days. I wonder if there is something that the AP is hanging on to that prevents the cores from obtaining a refreshed IP?

@peekay123 I am just as confused on the relationship.

I’ll change the 5GHz SSID, and reduce the DHCP lease time and report back.


any progress on this? My issue may be similar…
Developed code and everything seemed to be working in fine (running in semi-automatic mode) can post code upon request. I had them working at my house, my friends houses, and work. All of a sudden they don’t connect at my house… They flash green.

I have not reset my router yet, as I thought I would see if there is anything else you figured out or want me to try before I reset my router and see what happens.

@jerome I’m not confident I understand the problem. After it happened last time I did two things.

  1. I changed the DHCP lease time to 60 minutes on my router
  2. I changed the SSID on the 5GHz band to be different from the 2.4GHz band.

I have not had the flashing green occur again. It’s been 26 days so hopefully that had addressed the problem. My goal with the DHCP Lease time was to force the issue to occur sooner, but maybe that has helped address the issue. Unfortunately I can’t remember what it was prior. It may have been 24 hours.

Hope this helps, I’d be curious if the lease time addresses your problem.

I have a Cisco EA4500 router.

thanks for the reply @mtnscott,
You earlier post says “1440 or 24 hours” so your memory is good :smile:

I am setting up an experiment to run tonight after I get home… something like this

  1. take prototypes and try to connect via Spark app, TI SmartConfig app, and usb, testing connectivity between each try.
  2. take new spark core out of the box (I have a few untouched purchased about 4 weeks ago) and do the same.
  3. cycle power on the router, and repeat steps one and two
  4. Post and see if anyone has any insight.
  5. Wait and see if it happens again… I think I would try to repeat the issue (as in not change my lease times) to see if the problem re-occurs.

If you have anything else to try let me know

I think the number one thing on the list of things to try should be change the SSID of the 5GHz part of the router so that the cores cannot try to connect to it. If the 2.4GHz and 5GHz bands have different SSIDs I think you will have a lot fewer problems.

When I experienced this problem before I did the following to a core that was flashing green -

  1. reboot it - no effect
  2. reflash it - no effect
  3. reset it to factory firmware, set WiFi credentials and flash it with my firmware - no effect

The only way to get it online again was to reboot the router. So clearly the problem was something to do with the interaction between the router and core.

After this happened the first time and I tried to remedy it on the core side and eventually just rebooted the router, the next time it happened I left the cores alone and just rebooted the router, the cores reconnected and resume normal activity on their own.

    • Since your cores are not connected to WiFi, indicated by flashing green, nothing will work that depends on the network.
    • this will probably work as your router has never seen the new cores before.
    • I expect this will correct the issue for now.
    • this will be interesting, please post back.

@bko my router doesn’t have 5GHz

@mtnscott thanks for your expectations. for #2 (new cores). The weird thing is I think they one that is acting badly only got unboxed 2 weeks ago. so I will be interested to test this and not rely on memory.