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From:   =?utf-8?Q?Zbyn=C4=9Bk_Kocur?= <zbynek.kocur@fel.cvut.cz>
Message-Id: <7FD0B694-64B5-433D-B451-A0FD4DF32AED@fel.cvut.cz>
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Subject: Re: [PATCH] iio: srf04: fix wrong limitation in distance measuring
Date:   Mon, 9 Sep 2019 08:53:57 +0200
In-Reply-To: <20190907094632.kalkqtkxlfphdx4w@arbad>
Cc:     Jonathan Cameron <jic23@kernel.org>, linux-iio@vger.kernel.org,
        knaack.h@gmx.de, lars@metafoo.de, pmeerw@pmeerw.net,
        linux-kernel@vger.kernel.org
To:     Andreas Klinger <ak@it-klinger.de>
References: <20190623122909.hhzskp6k5vm4wify@arbad>
 <20190626192134.4b7aed3c@archlinux>
 <03D5EE82-D6C7-4A03-9404-45B48F1EF5B6@fel.cvut.cz>
 <20190626204936.2756cefd@archlinux>
 <3372AFA8-5AD0-4044-9718-D3E2B76EDFAE@fel.cvut.cz>
 <20190907094632.kalkqtkxlfphdx4w@arbad>
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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-s=
r04/).

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@fel.cvut.cz
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@it-klinger.de> wrote:
>=20
> Hi Zbynek,
>=20
> do you have any feedback for us?
>=20
> Thank you,
>=20
> Andreas
>=20
>=20
> Zbyn=C4=9Bk Kocur <zbynek.kocur@fel.cvut.cz> schrieb am Mi, 26. Jun =
21:50:
>> Thank you, i will write a feedback after testing.
>>=20
>>=20
>> Zbynek
>> ---
>> email: zbynek.kocur@fel.cvut.cz
>> phone: +420 224 354 054
>> web: http://www.fel.cvut.cz
>> Department of Telecommunications Engineering
>> Faculty of Electrical Engineering
>>=20
>>> On 26 Jun 2019, at 21:49, Jonathan Cameron <jic23@kernel.org> wrote:
>>>=20
>>> No rush, it's a clear fix anyway so we can queue this up
>>> in the rc phase of the next kernel cycle!
>>=20
>=20
> --=20
> Andreas Klinger
> Grabenreith 27
> 84508 Burgkirchen
> +49 8623 919966
> ak@it-klinger.de
> www.it-klinger.de
> www.grabenreith.de


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