Re: [PATCH] iio: srf04: fix wrong limitation in distance measuring

From: ZbynÄk Kocur
Date: Mon Sep 09 2019 - 03:07:54 EST


Hi Andreas,

I'm so sorry for the delay. I was working on another project now, and I wasn't entirely devoted to this. I looked at it at the weekend and the modified code is working. I have only tested OpenWRT in build - r10204-38b22b1, kernel 4.14.125. I do not expect complications on other platforms.

I tried it on several sensors. I was primarily interested in JSN-SR04T (https://www.makerguides.com/jsn-sr04t-arduino-tutorial/). I have also verified other designs (https://randomnerdtutorials.com/complete-guide-for-ultrasonic-sensor-hc-sr04/).

It generally works. Relatively accurate for the area up to 2.5 m. However, if the distance is longer, it starts to fizz, depending on the sensor design. It is a property of used HW and its construction.

I do not know how to do this in the development of drivers, whether it makes sense to put a filter directly into the driver or at least pull the maximum distance parameter as a variable?

Anyway, the change made works.

Zbynek
---
email: zbynek.kocur@xxxxxxxxxxx
phone: +420 224 354 054
web: http://www.fel.cvut.cz
Department of Telecommunications Engineering
Faculty of Electrical Engineering

> On 7 Sep 2019, at 11:46, Andreas Klinger <ak@xxxxxxxxxxxxx> wrote:
>
> Hi Zbynek,
>
> do you have any feedback for us?
>
> Thank you,
>
> Andreas
>
>
> ZbynÄk Kocur <zbynek.kocur@xxxxxxxxxxx> schrieb am Mi, 26. Jun 21:50:
>> Thank you, i will write a feedback after testing.
>>
>>
>> Zbynek
>> ---
>> email: zbynek.kocur@xxxxxxxxxxx
>> phone: +420 224 354 054
>> web: http://www.fel.cvut.cz
>> Department of Telecommunications Engineering
>> Faculty of Electrical Engineering
>>
>>> On 26 Jun 2019, at 21:49, Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
>>>
>>> No rush, it's a clear fix anyway so we can queue this up
>>> in the rc phase of the next kernel cycle!
>>
>
> --
> Andreas Klinger
> Grabenreith 27
> 84508 Burgkirchen
> +49 8623 919966
> ak@xxxxxxxxxxxxx
> www.it-klinger.de
> www.grabenreith.de

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