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by perfo
Mon Apr 15, 2019 8:47 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: interface with digital calipers
Replies: 52
Views: 9383

Re: interface with digital calipers

I find it handy to have absolute positions (relative to end stops) and relative positions but with the RPI and big screen you can have as many as you like...
by perfo
Sat Apr 13, 2019 11:42 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: interface with digital calipers
Replies: 52
Views: 9383

Re: interface with digital calipers

I like the look of that.
An RPI with a big monitor and some extra functionality like relative positions etc would finish it off .. Oh and maybe a box or tow but then half my stuff never actually makes it in to a proper housing...
by perfo
Fri Mar 29, 2019 11:55 am
Forum: General programming discussion
Topic: Read Pixel colour from screen.
Replies: 20
Views: 1373

Re: Read Pixel colour from screen.

So could I feed it jpegs with a C script ?
So I'd feed it jpeg 1 then switch my GPIO on then feed it Jpeg 2 then GPIO off etc ?
by perfo
Thu Mar 28, 2019 11:48 am
Forum: General programming discussion
Topic: Read Pixel colour from screen.
Replies: 20
Views: 1373

Re: Read Pixel colour from screen.

Great thanks. another avenue to explore this weekend.
by perfo
Thu Mar 28, 2019 11:01 am
Forum: General programming discussion
Topic: Read Pixel colour from screen.
Replies: 20
Views: 1373

Re: Read Pixel colour from screen.

out of interest , would you know of a player that does the opposite of Mencoder ? That's is I give it jpegs and it plays them as a video ?
by perfo
Thu Mar 28, 2019 11:00 am
Forum: General programming discussion
Topic: Read Pixel colour from screen.
Replies: 20
Views: 1373

Re: Read Pixel colour from screen.

Thanks for the suggestion. I've got a few things to have a bash at this weekend....
by perfo
Wed Mar 27, 2019 1:01 pm
Forum: General programming discussion
Topic: Read Pixel colour from screen.
Replies: 20
Views: 1373

Re: Read Pixel colour from screen.

Ah the ol reliable VLC... I'll give it a bash and see what happens...
Thanks
by perfo
Wed Mar 27, 2019 11:30 am
Forum: General programming discussion
Topic: Read Pixel colour from screen.
Replies: 20
Views: 1373

Re: Read Pixel colour from screen.

Do you know of any players I could try ?
by perfo
Wed Mar 27, 2019 9:32 am
Forum: General programming discussion
Topic: Read Pixel colour from screen.
Replies: 20
Views: 1373

Re: Read Pixel colour from screen.

Thanks for the detailed answer you put some effort I to it and that is appreciated. I did manage to get pixel stuff from the FB but as JamesH points out that was before I found out OmxPlayer didn't use the frame buffer and thus I couldn't make head nor tail out of the info I was managing to get. I b...
by perfo
Sun Mar 24, 2019 8:28 pm
Forum: Automation, sensing and robotics
Topic: Read Data from Pi without WIFI
Replies: 3
Views: 220

Re: Read Data from Pi without WIFI

Thanks for the answers. If I could find an app that already does it over blue tooth for apple and android then that would be a great possibility (though I haven't found one yet). I could write one for android (possibly) but it's far too much faff to publish one for apple stuff. The problem with your...
by perfo
Sun Mar 24, 2019 2:42 am
Forum: Automation, sensing and robotics
Topic: Read Data from Pi without WIFI
Replies: 3
Views: 220

Read Data from Pi without WIFI

Hello All, I'm not quite sure how to word this question so I will start with what I am trying to achieve. The RPI will be happily reading data presented to its GPIO and I want to be able to view this data on a standard phone. The easiest way I can think of is set up the RPI as a web server and creat...
by perfo
Thu Mar 14, 2019 4:56 pm
Forum: General programming discussion
Topic: Read Pixel colour from screen.
Replies: 20
Views: 1373

Re: Read Pixel colour from screen.

Thanks for the tips James... I'm using omxplayer to play a video and trying to grab a pixel from that and so far I wasn't getting much sense. Maybe you've just explained why that is... I have other posts on this forum asking questions as I've tried different ways to achieve my project. My project is...
by perfo
Thu Mar 14, 2019 12:48 pm
Forum: General programming discussion
Topic: Read Pixel colour from screen.
Replies: 20
Views: 1373

Re: Read Pixel colour from screen.

Hello Jamesh I only want to read one pixel per frame no matter what the resolution is. I was hoping with only reading one it may enable it to be speedy enough, I'm not interested in the camera for this application so that's not a problem but what do you mean by the video display is not presented to ...
by perfo
Thu Mar 14, 2019 10:10 am
Forum: General programming discussion
Topic: Read Pixel colour from screen.
Replies: 20
Views: 1373

Re: Read Pixel colour from screen.

Thanks Andyroo.

The thing is I need to do this live so whatever method I use has to be able to process it at least as fast as the frame rate of the video (ie 60 FPS)
by perfo
Thu Mar 14, 2019 8:44 am
Forum: General programming discussion
Topic: Read Pixel colour from screen.
Replies: 20
Views: 1373

Read Pixel colour from screen.

I've put this in the general programming as I'm open to suggestions whether in C or python. I would prefer python as I understand it a lot more but maybe able to work with C if it isn't too complex. So As I stated I want to pick a pixel at (X,Y) being displayed on screen (HDMI output). is the Frame ...
by perfo
Thu Mar 14, 2019 8:35 am
Forum: Graphics, sound and multimedia
Topic: Shutter Glasses
Replies: 5
Views: 534

Re: Shutter Glasses

I'm not getting any tearing though so the frame vs refresh can't be that far out of sync...
Is there any way to force the fps and refresh to be in sync ?
by perfo
Thu Mar 14, 2019 8:33 am
Forum: OpenMAX
Topic: Display image as fast as possible
Replies: 7
Views: 945

Re: Display image as fast as possible

Problem with me is I believed the hype about basic and vba / visual basic being the future when MS decided to include it in there packages. I started with C , fortran , pascal and the usual crew but dropped them 30 years ago.. Not that I was particularly good then but my older brain has difficulty g...
by perfo
Wed Mar 13, 2019 9:32 pm
Forum: OpenMAX
Topic: Display image as fast as possible
Replies: 7
Views: 945

Re: Display image as fast as possible

Nope still no closer.
Is there a way python can render images using the GPU ? Maybe some sort of MMAL interface that hides all the complexities from me ?
by perfo
Wed Mar 13, 2019 7:22 pm
Forum: OpenMAX
Topic: Display image as fast as possible
Replies: 7
Views: 945

Re: Display image as fast as possible

Ah penny dropped about Jpegs.. there isn't a way to present a Jpeg in your example. It has to be de coded in to a memory location first and the memory location sent to the renderer. So Off to read more on how to use a Image_decoder to get the jpeg in the right format. Still none the wiser what to do...
by perfo
Wed Mar 13, 2019 6:27 pm
Forum: OpenMAX
Topic: Display image as fast as possible
Replies: 7
Views: 945

Re: Display image as fast as possible

being Pi specific isn't a prob at all as that's where I'm hoping to do it all. I've been digging around the MMAl business for a few hours and not a lot further on than when I started :-( I had a look at that example you kindly provided but can't work out for the life of me where I'd stick in a Jpeg ...
by perfo
Wed Mar 13, 2019 4:48 pm
Forum: OpenMAX
Topic: Display image as fast as possible
Replies: 7
Views: 945

Re: Display image as fast as possible

Nope, I'm not brought in to any particular way, as long as I can do it.. I'll go away and read up on MMAL. If I'm understanding it right are you saying MMAL doesn't use hardware acceleration and yet still manages 60fps or more ? That's impressive.. Ok off to read , thanks for the tip. I'll report ba...
by perfo
Wed Mar 13, 2019 10:08 am
Forum: Graphics, sound and multimedia
Topic: Shutter Glasses
Replies: 5
Views: 534

Re: Shutter Glasses

Grrr, It doesn't work. Looking at the Vsync on my scope I can see a nice train of pulses. With my code above this gets swapped to a nice square wave with the pulse going on with one Vsync pulse and going off with the next sync pulse. At a 60hz refresh rate these pulses are 16 ms so equal to 60 frame...
by perfo
Wed Mar 13, 2019 9:52 am
Forum: OpenMAX
Topic: Display image as fast as possible
Replies: 7
Views: 945

Display image as fast as possible

I'm trying to display a series of still images as fast as possible. Hoping for 60fps or more. I can use any image format if one is preferable to others (involves less decoding maybe) So a few questions really. Is OpenMAX going to be the way to go ? I may be way off beam here but I'm thinking as omxp...
by perfo
Sun Mar 10, 2019 2:58 am
Forum: Graphics, sound and multimedia
Topic: Shutter Glasses
Replies: 5
Views: 534

Re: Shutter Glasses

Well thanks for all your comments folk :-) I've included what I've found incase it helps someone else. I finally discounted most avenues as they didn't keep in sync or gave other problems . The DPI and HDMI can be set up to mirror one an another and makes it easy to grab the Vsync off the GPIO but t...
by perfo
Wed Mar 06, 2019 3:10 am
Forum: Graphics, sound and multimedia
Topic: Shutter Glasses
Replies: 5
Views: 534

Re: Shutter Glasses

There is a great tut on stop motion film making here https://projects.raspberrypi.org/en/projects/push-button-stop-motion Using the code from there avconv -r 10 -i animation/frame%03d.jpg -qscale 2 animation.h264 to make a file out of my frames and then omxplayer animation.h264 to play it This works...

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