On 30/03/2019 18:49, polygonum_on_google wrote:
Just got back from a little trip in the car. It has speed limit sign recognition built-in. Most of the time, it works pretty well. But today it was going crazy. Missing some signs. Telling me I am over-limit when I go from a 20 zone to a 30 zone and was doing under 20 €“ though it did €œsee€� the sign correctly! Not changing from indicating over-limit even when I dropped speed even further. (At no point was I actually over-limit - according to speedo and me!)

A few miles down the road, back to working entirely properly.

Now I could take all sorts of wild guesses as to the cause, and usually I would. The thing is, it misbehaved in exactly the same way, on the same bit of road, a week or two ago. Not just a straight road but a very windy route that varies from 60 through 30 and 20 several times, back up to 60, then 40 and finally 60 again. At no point in-between has it appeared to misbehave at all. On both occasions I had driver well over 20 miles before getting to this location €“ and about 20 miles after €“ and worked perfectly.

While these devices are merely assistants to the driver, it is no big deal. If they start to actually control speed, this could be quite an issue.

Any ideas what could be causing these issues?

Could be an EMC issue - system being overwhelmed by strong RF etc...


--
Cheers,

John.

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On Tuesday, 2 April 2019 22:31:12 UTC+1, John Rumm wrote:
On 30/03/2019 18:49, polygonum_on_google wrote:
Just got back from a little trip in the car. It has speed limit sign recognition built-in. Most of the time, it works pretty well. But today it was going crazy. Missing some signs. Telling me I am over-limit when I go from a 20 zone to a 30 zone and was doing under 20 €“ though it did €œsee€� the sign correctly! Not changing from indicating over-limit even when I dropped speed even further. (At no point was I actually over-limit - according to speedo and me!)

A few miles down the road, back to working entirely properly.

Now I could take all sorts of wild guesses as to the cause, and usually I would. The thing is, it misbehaved in exactly the same way, on the same bit of road, a week or two ago. Not just a straight road but a very windy route that varies from 60 through 30 and 20 several times, back up to 60, then 40 and finally 60 again. At no point in-between has it appeared to misbehave at all. On both occasions I had driver well over 20 miles before getting to this location €“ and about 20 miles after €“ and worked perfectly.

While these devices are merely assistants to the driver, it is no big deal. If they start to actually control speed, this could be quite an issue.

Any ideas what could be causing these issues?

Could be an EMC issue - system being overwhelmed by strong RF etc...

I can't think of any obvious reasons for there being high RF there. But in the absence of other explanations, it deserves more consideration and investigation.