10 ms·

>the IoT ecosystem needs to give surprise interference some consideration as well. In the early days of Lockitron we were using the 433MHz bandwidth. We would

>the IoT ecosystem needs to give surprise interference some consideration as well. In the early days of Lockitron we were using the 433MHz bandwidth. We would occasionally experience state wide non-response to our locks despite having full backend network connectivity. Eventually we tracked the problem down to sunspots. Coming from software it was one of the more bizarre things to debug.

robterrell 10y ago
Seriously, sunspots? Would love to see more about this. Did you write it up anywhere?
- paulgerhardt 10y ago
  I mean...there's not much more to the story than that. 2011 was a bit crazy for the Sun [1]. There were two or three x-class flares that jammed transmission for a short period. Multiple customer reports coincided with the February and August events that year. The February flare was caused by sunspot 1158 [2] and the August flare was caused by sunspot 1263 [3]. Deploying those locks across hundreds of locations we saw quite a bit of unusual stuff. Locks would work fine on one side of a building but not the other - the bad side faced the San Francisco bay - deduced it was from all the SF/Oakland Radio traffic. Another location would experience problems during baseball games. (Stadium was next door). Cell tower guys have even crazier stories. One involves my colleague who had a bitcoin mine in his garage. Few dozen graphics cards humming along at ~900MHz knocked out the whole voice uplink for 4 square miles. (He happened to be pretty close to the cell tower and raised the noise floor just enough to make cell phones all but useless.) Working in ISM bands can be brutal, but it will teach you a lot and quickly. [1] http://www.space.com/14060-2011-restless-sun-solar-activity-review.html http://www.space.com/14060-2011-restless-sun-solar-activity-... [2] http://www.space.com/10862-sun-erupts-powerful-solar-flare.html http://www.space.com/10862-sun-erupts-powerful-solar-flare.h... [3] https://www.youtube.com/watch?v=heVeq_anewU https://www.youtube.com/watch?v=heVeq_anewU
- CamperBob2 10y ago
  The "sunspots" explanation doesn't pass the smell test for several reasons. It's the sort of thing you tell a customer to get them to go away and give the problem a chance to resolve itself. More likely, in that part of the spectrum, they were seeing adverse effects from (probably undisclosed) military R&D activities. Might as well have been sunspots, for all they could've done about it.
  - yanowitz 10y ago
    For the less-RF-literate (such as myself), can you please elaborate on the several reasons?
    - brians 10y ago
      Sunspots don't cause appreciable increase in RF background at any frequency at sea level. They cause lots more excitation of the ionosphere, so shortwave radio signals bounce better and further, but nothing up in UHF. But other phenomena correlated with sunspots do cause UHF interference, so while wrong on the details I generally believe the story.
      - CamperBob2 10y ago
        But other phenomena correlated with sunspots do cause UHF interference What would be some examples of such phenomena, bearing in mind that we're talking about very short-range wireless links in a band shared with primary military users? It's not as if conflicts in that band haven't arisen before: http://www.w5yi.org/ama_news_article.php?id=191l http://www.w5yi.org/ama_news_article.php?id=191l Another example: http://www.tdsupplies.com/articles/395_MHz_Military_Radio_Remote_Interference.html http://www.tdsupplies.com/articles/395_MHz_Military_Radio_Re...
        brians 10y ago
        X-ray flares, which get through the ionosphere and mess with VHF and UHF. The collapse of the magnetosphere on the night side following impact of a coronal mass ejection—which not only make a lot of VHF and UHF noise, they have enough power to just break a device.
tzs 10y ago
Another good one is the military. A coworker lives a few miles from the navy base in Bremerton, Washington, and a couple times a year they do some radio testing that completely blocks his garage door opener. His garage only has the one door, and it has no manual override from outside, so when this happens his car is stuck there until the navy finishes testing. This is an area where IOT makes some sense. If you use an unlicensed frequency using the rule that allows use of such frequencies as long as power is very low, you risk some licensed user legally operating with much more power will stomp all over you, as is the case with the navy. If you use IOT, that is much less likely. The frequencies used by WiFi are primarily allocated to other services, and so there is some risk that someone will legally stomp all over your WiFi, that risk is a lot less. First, WiFi bands start at 2.4 GHz and go up from there. At those frequencies range is much more limited than it is at lower frequencies such as those typically used in current garage door openers. So even if someone is doing something high powered on those frequencies, it will likely only wipe out WiFi in a small area, rather than for many miles around. Second, WiFi is widespread enough that those who might interfere probably use WiFi themselves, and so might be inclined to use some other frequencies available to them so as to not wipe out their own WiFi. Similar arguments apply to cellular internet, but more strongly because in the case of cellular, I believe the cellular companies are the users who have priority for those frequencies. This, an IOT garage door opener, connected on your home WiFi, that you can access via your cell phone from your car either via the cell phone using your home access point of over your cellular service, seems like it would possibly be the way to go nowadays (assuming you can secure the damn thing reasonably). In the case specifically of garage door openers, though, I'd also consider doing it optically or ultrasonically, instead of via radio.
- Domenic_S 10y ago
  > so when this happens his car is stuck there until the navy finishes testing. Huh.. he should be able to manually release the door from the inside (that's what the hanging handle [0] is for) and open/close it manually. Or hook up a wired keypad [1] An interesting story regardless! [0] http://precisiondoor.net/uploads/content/garage-door-opener-emergency-release.png http://precisiondoor.net/uploads/content/garage-door-opener-... [1] https://www.amazon.com/Domino-Engineering-KEYLESS-ENTRY-SYSTEM/dp/B0013OBU8S/ref=pd_sim_107_3?ie=UTF8&psc=1&refRID=TY8ZW2SZ8PDWKX4JKVNF https://www.amazon.com/Domino-Engineering-KEYLESS-ENTRY-SYST...
Zardoz84 10y ago
If you use a lower freq band, you could discover the amazing world of the massive effect of sun spots, day/night cycle, mountains and buildings reflexions and the ionosphere effects. PD: My father is a amateur radio operator that on his good times won some prices talking with people on the other side of the world with a relative low power signal.

robterrell 10y ago

Seriously, sunspots? Would love to see more about this. Did you write it up anywhere?

paulgerhardt 10y ago
I mean...there's not much more to the story than that. 2011 was a bit crazy for the Sun [1]. There were two or three x-class flares that jammed transmission for a short period. Multiple customer reports coincided with the February and August events that year. The February flare was caused by sunspot 1158 [2] and the August flare was caused by sunspot 1263 [3]. Deploying those locks across hundreds of locations we saw quite a bit of unusual stuff. Locks would work fine on one side of a building but not the other - the bad side faced the San Francisco bay - deduced it was from all the SF/Oakland Radio traffic. Another location would experience problems during baseball games. (Stadium was next door). Cell tower guys have even crazier stories. One involves my colleague who had a bitcoin mine in his garage. Few dozen graphics cards humming along at ~900MHz knocked out the whole voice uplink for 4 square miles. (He happened to be pretty close to the cell tower and raised the noise floor just enough to make cell phones all but useless.) Working in ISM bands can be brutal, but it will teach you a lot and quickly. [1] http://www.space.com/14060-2011-restless-sun-solar-activity-review.html http://www.space.com/14060-2011-restless-sun-solar-activity-... [2] http://www.space.com/10862-sun-erupts-powerful-solar-flare.html http://www.space.com/10862-sun-erupts-powerful-solar-flare.h... [3] https://www.youtube.com/watch?v=heVeq_anewU https://www.youtube.com/watch?v=heVeq_anewU
CamperBob2 10y ago
The "sunspots" explanation doesn't pass the smell test for several reasons. It's the sort of thing you tell a customer to get them to go away and give the problem a chance to resolve itself. More likely, in that part of the spectrum, they were seeing adverse effects from (probably undisclosed) military R&D activities. Might as well have been sunspots, for all they could've done about it.
- yanowitz 10y ago
  For the less-RF-literate (such as myself), can you please elaborate on the several reasons?
  - brians 10y ago
    Sunspots don't cause appreciable increase in RF background at any frequency at sea level. They cause lots more excitation of the ionosphere, so shortwave radio signals bounce better and further, but nothing up in UHF. But other phenomena correlated with sunspots do cause UHF interference, so while wrong on the details I generally believe the story.
    - CamperBob2 10y ago
      But other phenomena correlated with sunspots do cause UHF interference What would be some examples of such phenomena, bearing in mind that we're talking about very short-range wireless links in a band shared with primary military users? It's not as if conflicts in that band haven't arisen before: http://www.w5yi.org/ama_news_article.php?id=191l http://www.w5yi.org/ama_news_article.php?id=191l Another example: http://www.tdsupplies.com/articles/395_MHz_Military_Radio_Remote_Interference.html http://www.tdsupplies.com/articles/395_MHz_Military_Radio_Re...
      - brians 10y ago
        X-ray flares, which get through the ionosphere and mess with VHF and UHF. The collapse of the magnetosphere on the night side following impact of a coronal mass ejection—which not only make a lot of VHF and UHF noise, they have enough power to just break a device.

tzs 10y ago

Another good one is the military. A coworker lives a few miles from the navy base in Bremerton, Washington, and a couple times a year they do some radio testing that completely blocks his garage door opener. His garage only has the one door, and it has no manual override from outside, so when this happens his car is stuck there until the navy finishes testing. This is an area where IOT makes some sense. If you use an unlicensed frequency using the rule that allows use of such frequencies as long as power is very low, you risk some licensed user legally operating with much more power will stomp all over you, as is the case with the navy. If you use IOT, that is much less likely. The frequencies used by WiFi are primarily allocated to other services, and so there is some risk that someone will legally stomp all over your WiFi, that risk is a lot less. First, WiFi bands start at 2.4 GHz and go up from there. At those frequencies range is much more limited than it is at lower frequencies such as those typically used in current garage door openers. So even if someone is doing something high powered on those frequencies, it will likely only wipe out WiFi in a small area, rather than for many miles around. Second, WiFi is widespread enough that those who might interfere probably use WiFi themselves, and so might be inclined to use some other frequencies available to them so as to not wipe out their own WiFi. Similar arguments apply to cellular internet, but more strongly because in the case of cellular, I believe the cellular companies are the users who have priority for those frequencies. This, an IOT garage door opener, connected on your home WiFi, that you can access via your cell phone from your car either via the cell phone using your home access point of over your cellular service, seems like it would possibly be the way to go nowadays (assuming you can secure the damn thing reasonably). In the case specifically of garage door openers, though, I'd also consider doing it optically or ultrasonically, instead of via radio.

Domenic_S 10y ago
> so when this happens his car is stuck there until the navy finishes testing. Huh.. he should be able to manually release the door from the inside (that's what the hanging handle [0] is for) and open/close it manually. Or hook up a wired keypad [1] An interesting story regardless! [0] http://precisiondoor.net/uploads/content/garage-door-opener-emergency-release.png http://precisiondoor.net/uploads/content/garage-door-opener-... [1] https://www.amazon.com/Domino-Engineering-KEYLESS-ENTRY-SYSTEM/dp/B0013OBU8S/ref=pd_sim_107_3?ie=UTF8&psc=1&refRID=TY8ZW2SZ8PDWKX4JKVNF https://www.amazon.com/Domino-Engineering-KEYLESS-ENTRY-SYST...

Zardoz84 10y ago

If you use a lower freq band, you could discover the amazing world of the massive effect of sun spots, day/night cycle, mountains and buildings reflexions and the ionosphere effects. PD: My father is a amateur radio operator that on his good times won some prices talking with people on the other side of the world with a relative low power signal.