Rotary encoder project

frietpan · 2015-12-05T08:02:33.000Z

After a few days of digging i finally found where the rotary encoder stuff was installed.

/sys/module/rotary_encoder

I still don’t know how I tie it to GPIO 16 and 17 any hints are welcome.

j-maathuis · 2015-12-05T08:04:13.000Z

/me is still awake and a bit bored.

Connecting and starting up the GL-AR150.

Digging a bit into it.

frietpan · 2015-12-05T08:17:27.000Z

Archaeology of the 22nd century… someone dug up a severely hacked AR150 and screamed AAAAAAAAAAAAAAAAAAAAAAaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa WTF???

j-maathuis · 2015-12-05T08:19:05.000Z

/sys/module/rotary_encoder is a directory
I went to /sys/module/rotary_encoder/drivers/platform:rotary-encoder which is a symlink to /sys/bus/platform/drivers/rotary-encoder
This directory contains the directory’s “bind”, “module”, “uevent” and “unbind”.
After some searching on Google I found out we probably have to bind a driver: Manual driver binding and unbinding [LWN.net]
I’ll keep on investigating now, sooner or later.

j-maathuis · 2015-12-05T08:34:35.000Z

Às mentioned above in post http://www.gl-inet.com/forums/topic/rotary-encoder-project/#post-7363 you have to assign something to a key called “rotary-gpio-custom.bus0” (and also bus 1 till 3).

Here is a topic that describes not exactly the same, but about pressing GPIO keys: http://www.avrfreaks.net/forum/gpio-key-device-doesnt-get-installed

I did see something in the topicstart:

I wonder if there should be a directory like it is in /sys/bus/platform/drivers/leds-gpio bind leds-gpio.2 uevent unbind

Maybe this will gice us some clue?

frietpan · 2015-12-05T10:37:11.000Z

just got home,
I think you could be right,

Something in the area of gpio_a.16 and another with gpio_b.17 This needs a few days to find a braincell that’s a bit more digitally minded then the others

rotary-gpio-custom.bus0.gpio_a.16
rotary-gpio-custom.bus0.gpio_a.17

And also for id, steps, axis?

Or am I again thinking in the wrong direction here? (or too far ahead)

frietpan · 2015-12-05T17:11:13.000Z

I think bus1, bus2 and bus3 can be left empty. The driver can handle 4 rotaties I have read somehere

But it’s not clear what values are expected for id, and axis.

Steps is most likely “20” that’s the number of steps of the rotary to make 1 full circle.

I wonder if we can find in the sourcecode what kind of value’s it expects?

frietpan · 2015-12-08T05:19:16.000Z

after a lot of digging i cae across this page: http://lxr.free-electrons.com/source/Documentation/input/rotary-encoder.txt

It looks like this should now be all the info i need… and now i need to look how to enter the correct commands to set these values. That’s for tomorrow…

I need <id>,<steps>,<axis>,<gpioa>,<gpiob>,<inverted>

These are the values that I have in mind:

id = 0
steps = 20,
axis = ABS_X,
gpio_a = 16,
gpio_b = 17,
inverted = 0,

rene · 2015-12-08T08:37:37.000Z

Hey Frietpan first greetings to the netherlands from germany near the border !

You could take a look here: Build Your Own Wifi Radio : 14 Steps (with Pictures) - Instructables this guy is using a openwrt router to make a webradio,using a rotary encoder with a microcontroller. i think it could be done by adding a arduino nano or something else into the router this should be a solution for your problem

also take a look at this: Building a Wifi Radio – Part 8, Adding a Tuning Control | MightyOhm

frietpan · 2015-12-09T04:52:53.000Z

Greetings Rene! Are you in the Aachen area perhaps? (near the Dutch mountains)

Thats a nice project! However, it uses an ‘expensive’ atmel to do the GPIO stuff. It looks less complicated then the route I took. Once this encoder stuff is figured out it should make things more easy. By connecting the encoder directly to the SoC there is no more need to use an extra chip do add a basic selector switch / control knob.

I want to use it as a volume knob / light dimmer and also as a OpenWrt config selector. … yeah too many ideas…

The most practical use would be a config selector for a travel router. By making additional config folders ie /config1, /config, /config3, etc. When you turn the knob then another folder is used. This way you could store an endless number of configurations… Just by connecting a rotary to the GPIO’s But I’m not there yet… Getting close though. I’m now at the point where i have to figure out what kmod-rotary-gpio-custom wants to know exactly.

I have tried a few things but since i’m not comfortable with it yet i hope i don’t mess up anything.

rene · 2015-12-09T05:37:38.000Z

Yes i understand, but i´m not sure if the soc can handle the timings of the LOW/High´s from the encoder… sadly my rotary encoder is on its way from china to germany, will test in about three weeks xD

i´m located Near Borken (near in the Netherlands Winterswijk)

frietpan · 2015-12-09T08:18:11.000Z

Cool,

I also had my doubts, but afterall there is kmod-input-gpio-encoder and kmod-rotary-gpio-custom these drivers seem specifically made for using encoders on GPIO pins. A little bit hard to understand how they work, but it’s all there and they seem to exist for quiet some time for linux. And the AR9331 SoC seems to be modern enough. It would be great if someone with more knowledge would jump in and tell us the secrets but it looks like we are the pioneering pirates. HAR HAR!

Now i also have to build a Radio. Then I can tune in to one of the streams from Culturserver.de

Borken That’s not too far from here. It’s a little up north from Airport Weeze right?

I’m 15 minutes south of Eindhoven.

rene · 2015-12-09T09:35:52.000Z

i´m good thank you, i´ve just ordered a rotary from the uk! http://www.ebay.de/itm/311219577453 looks really nice

Should be arriving in a few days i hope! Yes the Radio Project does looks good sadly i´m not good at building cases!

i´m located in the Ruhrgebiet,Eindhoven is 1 1/2 hour far away from here by car (144km)

frietpan · 2015-12-10T04:50:40.000Z

It even has all the resistors mounted! In my case the pull-up of de SW was not mounted.

Plastic breadboxes and tupperware boxes make low cost enclosures for prototypes.

Ruhrgebiet now I have to download a few Schimanski episodes to get in the mood and make plans for a visit.

rene · 2015-12-10T08:38:12.000Z

Schimanski i´m waaaaaayyy too young for this! (25 years old)

but if u come to the ruhrgebiet we should drink a beer!

hope the rotary encoder arrives soon so i can compile my own openwrt and do a little bit soldering!^^

Will share my results for sure

j-maathuis · 2015-12-10T08:40:24.000Z

That would be great!

frietpan · 2015-12-11T06:14:37.000Z

I severely messed up a few minutes ago, I will re-flash and re-do all the things I did so far.

Schimi…, my age shows. Now I feel really old. HAHA - 44

frietpan · 2015-12-14T07:36:43.000Z

@Rene:

Compiling OpenWrt, i’m not at ease with it all. …Fear of making bricks…

I have read the OpenWrt wiki and on the GLi blog there is also a tutorial, the configuration procedure doesn’t look too difficult, but still it feels like there is a potential to make mistakes that can make bricks. Now if it is possible to flash images from USB then I would give it a try. How do you know that your self compiled image is safe to flash? Do you like to gamble, or do you have tools to repair bricks?

frietpan · 2015-12-23T14:54:05.000Z

@Rene I hope you discovered a few new clues. I have been trying to read up on this but it’s hard to find the right info, and even harder to understand it. (i’m still missing a few basic skills here)

I’m now going to play with Arduino and encoders to see if that can give more insight, though i doubt it will since Arduino is a bit different on this. Still i’m sure i’m going to learn something usefull.

rene · 2015-12-30T02:38:36.000Z

Hi Frietpan!

How are u?

Sorry for the delay in the response, i´ve still waiting for this little thing to arrive

damn christmas holidays