Date: Fri, 22 Aug 2014 00:43:45 -0300 From: Evandro Nunes <evandronunes12@gmail.com> To: Rui Paulo <rpaulo@felyko.com>, freebsd-arm@freebsd.org Subject: Re: HC-SR04 and FreeBSD Message-ID: <CAG4HiT4EbX=Lar_o8YZc5B51Yao1-B=Ebck0vQajyzoZwesWwQ@mail.gmail.com> In-Reply-To: <EA5A973C-960A-4B0F-A690-8AA9BF66244A@felyko.com> References: <CAG4HiT6wwbmSA_KWsgHOqdeZVOCUsdhRxDhMubvkG1tEwVH5Sw@mail.gmail.com> <5D802942-2D0F-4324-8212-C2871EEB6327@FreeBSD.org> <CAG4HiT6fiqVXMoqcJra1Yh8aFVbOcezP8rRqst6WC8aHuaF_rA@mail.gmail.com> <01562FB1-32C6-45AF-AB77-5BB80526E18C@FreeBSD.org> <CAG4HiT4kKz18iauXfuF0Dpv-USghunssUvwkTF7bDx_gE_VS2w@mail.gmail.com> <CCD5AEE5-798D-4EAC-BAE7-A086DE55B5D2@FreeBSD.org> <CAG4HiT6YUBCxXrK_KyRW6zTthPa-wDe=A9=CmMHQf-Gh54s7QA@mail.gmail.com> <EA5A973C-960A-4B0F-A690-8AA9BF66244A@felyko.com>
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On Thu, Aug 21, 2014 at 4:13 PM, Rui Paulo <rpaulo@felyko.com> wrote: > You can use an led instead of a multimeter. The point I'm trying to make > is to make sure the gpio number really corresponds to that port number. > still no success, but just an update... ok I added two led: pin 02: 0 gpio_2<IN> ===> echo (orange LED) pin 03: 0 gpio_3<OUT> ===> trigger (blue LED) pin 49: 0 gpio_49<IN> ===> previous echo and I have the two simple loops below. when I run loop1, BLUE LED blinks every second; when I run loop2 while loop1 stills run, ORANGE LED won't blink, and loop2 value still shows 0 value if I "gpioctl -c 2 OUT ; gpioctl -t 2", ORANGE LED will light, confirming LED is OK; thoses leds will light with 2-5v input... however I have no idea if the sonar output will range 2-5 or if it will be below 2 (i tried adding my hand very close and far away from the sensor but led was never lit) so I'd better use a multimeter for sure... loop1: while true ; do gpioctl -t 3; sleep .200; gpioctl -t 3 #gpioctl 3 sleep 1 done loop2: while true ; do gpioctl 2 sleep .500 done > > -- > Rui Paulo > > On 21 Aug 2014, at 11:44, Evandro Nunes <evandronunes12@gmail.com> wrote: > > On Thu, Aug 21, 2014 at 1:24 PM, Rui Paulo <rpaulo@freebsd.org> wrote: > >> On Aug 20, 2014, at 22:34, Evandro Nunes <evandronunes12@gmail.com> >> wrote: >> >> > On Thu, Aug 21, 2014 at 2:05 AM, Rui Paulo <rpaulo@freebsd.org> wrote: >> > On Aug 20, 2014, at 21:52, Evandro Nunes <evandronunes12@gmail.com> >> wrote: >> > >> > > On Thu, Aug 21, 2014 at 1:51 AM, Rui Paulo <rpaulo@freebsd.org> >> wrote: >> > > On Aug 20, 2014, at 21:48, Evandro Nunes <evandronunes12@gmail.com> >> wrote: >> > > >> > > > hello, >> > > > >> > > > ive got a ultrasonic sensor model HC-SR04 and a beaglebone black as >> well as >> > > > a cubieboard2, both running FreeBSD 11 built from crochet and wiki >> > > > instructions >> > > > >> > > > thanks to the help from loos@ I could manage to use a 5v relay >> with BBB >> > > > now, how can I read data from HC-SR04 sensor? do we have any library >> > > > available? or do we have any GPIO utility to do that? >> > > > btw how can I read values from GPIO pins when they are set to input? >> > > >> > > I wrote a library to handle GPIO on FreeBSD: >> > > >> > > https://bitbucket.org/rpaulo/libgpio >> > > >> > > very good :-) I will play with that >> > > >> > > You can also use the gpioctl utility in FreeBSD to read values. >> > > >> > > how? can you point me to any further reading, blog entry, or examples? >> > >> > There's a man page, but "gpioctl -c <PIN> IN" will set the pin in input >> mode. Then, "gpioctl <PIN>" will read the value. >> > >> > so this way I should read something from HC-SR04 echo pin on BBB? >> > I am using another gpio pin in output mode as a trigger, according to >> what I've read, 3.3v is OK as a trigger for this sonar >> > >> > but when I read the GPIO pin in input mode just as you mentioned, I >> always get a 0 value... >> > I am using BBB's P9_1 and P9_5 for +5v and ground, P9_21 as a trigger >> and P9_23 as echo; set GPIO 3 (P9_21) as output and GPIO 49 (P9_23) as input >> > I made a loop to read GPIO 49 every 100ms and another loop to trigger >> (gpioctl -t 3; sleep .100; gpioctl -t 3) every 2 seconds. >> > >> > what I am doing wrong? feeding 3.3v for 0.1 seconds as a trigger >> should't cause something to echo? >> >> Don't you have a multimeter? Have you measured the voltage on the output >> pin when you switch it to 0 and then back to 1? >> > > no, I don't have a working multimeter, mine is dead. I will buy another > one and test it as suggested, yes you are right, although I dont have an > idea on what value it should be expected > > but for curiosity, will gpioctl 49 show values anyhow equivalent to what a > multimeter would display? or I should not expect anything similar? > sorry for that question if this is too dummy, yes I completely lack on > GPIO basics, it's my first experience rss > > > > > >> -- >> Rui Paulo >> >> >> >> >
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