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by SteveA
Sun Feb 21, 2021 5:10 pm
Forum: Beginners
Topic: Adjust Screen Brightness programmatically x11 for HDMI and not LCD screens
Replies: 13
Views: 1350

Re: Adjust Screen Brightness programmatically x11 for HDMI monitors and not the small LCD panels

Please see the The Raspberry Pi notes/handbook/specs which can be downloaded. They explain the difference between a) HDMI/DVI monitors (such as used on standard PCs and can typically be 17" to 60" in size - these are the ones I use and can use a 1 or 2m video cable to drive them) and b) LC...
by SteveA
Sat Feb 20, 2021 7:22 pm
Forum: Beginners
Topic: Adjust Screen Brightness programmatically x11 for HDMI and not LCD screens
Replies: 13
Views: 1350

Re: Adjust Screen Brightness programmatically x11 for HDMI and not LCD screens

The monitors are plugged in via the 2 mini HDMI connectors on the RPI
by SteveA
Sat Feb 20, 2021 4:56 pm
Forum: Beginners
Topic: Adjust Screen Brightness programmatically x11 for HDMI and not LCD screens
Replies: 13
Views: 1350

Re: Adjust Screen Brightness programmatically x11 for HDMI and not LCD screens

Thanks, I had looked and tried xrandr and it appears to only work for attached LCD screens (panels) and not for HDMI plugged in monitors (single or dual). If anyone sees an update to be able to use xrandr on HDMI attached monitors then please share for future use. I have used the technique I describ...
by SteveA
Sun Jan 03, 2021 3:33 pm
Forum: Beginners
Topic: Adjust Screen Brightness programmatically x11 for HDMI and not LCD screens
Replies: 13
Views: 1350

Re: Adjust Screen Brightness programmatically x11 for HDMI and not LCD screens

rather than beating your head against an intractable problem. Sorry to have to reply again to correct your misunderstanding. I am not trying to alter the back light of an attached HDMI monitor (which can be DVI or even a TV screen, all of which could be LED, OLED, Plasma types, etc). To repeat, I n...
by SteveA
Sat Jan 02, 2021 1:35 pm
Forum: Beginners
Topic: Adjust Screen Brightness programmatically x11 for HDMI and not LCD screens
Replies: 13
Views: 1350

Re: Adjust Screen Brightness programmatically x11 for HDMI and not LCD screens

@Gfunkbus76 - I have had some success. I had looked at the pishad and because of the bad experience of having to spent 6 months rewriting a system when OpenVG was removed, I took the view of keeping it solely x11 as per my original question. In the lower levels of placing the pixels on the screen (i...
by SteveA
Sat Jan 02, 2021 12:29 pm
Forum: Beginners
Topic: Adjust Screen Brightness programmatically x11 for HDMI and not LCD screens
Replies: 13
Views: 1350

Re: Adjust Screen Brightness programmatically x11 for HDMI and not LCD screens

Thank you W H Heydt for your response which works for only attached LCD screens (which use the small port LCD screen port) and it does not work for the HDMI/DVI plug in monitors (of which I use 2.) May I please refer you to my original question which specifically says 'Adjust Screen Brightness progr...
by SteveA
Sat Aug 22, 2020 4:31 pm
Forum: Raspberry Pi OS
Topic: Buster update to Linux 5.4.51 v71+ Mon Aug 10 2020 - stops SPI
Replies: 1
Views: 977

Re: Buster update to Linux 5.4.51 v71+ Mon Aug 10 2020 - stops SPI

Sorted: The new OS update does not like defining the same (my spare unused) pin for both CE0 and CE1, whereas the previous Buster versions allowed it. I previously only used 1 pin so as not to take up GPIO, which could be used for other things. The cure is to define cs0 to a spare pin and cs1 to ano...
by SteveA
Fri Aug 21, 2020 9:53 am
Forum: Raspberry Pi OS
Topic: Buster update to Linux 5.4.51 v71+ Mon Aug 10 2020 - stops SPI
Replies: 1
Views: 977

Buster update to Linux 5.4.51 v71+ Mon Aug 10 2020 - stops SPI

I use RPI4 running Buster with my project, which is programmed in C, and everything has been working fine, eg SPI and I2C interface boards sending/receiving data. I have regularly updated the OS using the standard: sudo apt-get update sudo apt-get upgrade sudo apt-get dist-upgrade sudo apt-get autor...
by SteveA
Mon Nov 25, 2019 11:19 am
Forum: Beginners
Topic: Adjust Screen Brightness programmatically x11 for HDMI and not LCD screens
Replies: 13
Views: 1350

Adjust Screen Brightness programmatically x11 for HDMI and not LCD screens

I need to alter the screen brightness when a particular scientific project is run in a dark room/lab. The room is initially bright then turned dark when using such as UV, etc, and so the screen needs to be dimmed to match, so as still to be able to read the text/graphics. If the screen is not dimmed...
by SteveA
Wed Sep 18, 2019 3:39 pm
Forum: OpenVG
Topic: RPi 4 OpenVG Support?
Replies: 22
Views: 9609

Re: RPi 4 OpenVG Support?

I have just seen this post and have come across the same problem after buying a couple of RPI4 to start replacing the older RPI units in equipment. I use a derivative of A J Starks OpenVG library (runs over openvg) and unfortunately all projects have now come to a complete standstill. All applicatio...
by SteveA
Fri Sep 14, 2018 12:44 pm
Forum: Beginners
Topic: SAMBA - how to create multiple users without them being RPi users
Replies: 3
Views: 1715

Re: SAMBA - how to create multiple users without them being RPi users

Thanks DirkS, it works a treat. I can now create multiple RPI users without them being able to login to the RPI and without them having a home folder.

Much appreciated
Steve
by SteveA
Tue Sep 11, 2018 4:17 pm
Forum: Beginners
Topic: SAMBA - how to create multiple users without them being RPi users
Replies: 3
Views: 1715

SAMBA - how to create multiple users without them being RPi users

I can set the Raspberry Pi to samba share a specific folder for any user without any password and this works well. However I want to do the following I have not found a method to do this: 1. I need to have a common folder which I want to share. 2. I need 5 users to be able to login, each with a uniq...
by SteveA
Wed Nov 15, 2017 1:12 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: More than 2 SPI slaves
Replies: 19
Views: 12667

Re: More than 2 SPI slaves

Peter, from your original post, would you mind letting me know how you can disable the kernel from toggling CE0 or CE1 when using SPI because if that is what I have been trying to find out,
Thanks in advance
Steve
by SteveA
Thu Jan 05, 2017 8:36 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Chronodot with rtc-ds1307 Read Error
Replies: 4
Views: 4182

Re: Chronodot with rtc-ds1307 Read Error

Are you talking about this post or my reference to my recent post? Yes I am serious. And yes, I have followed the most recent methods of installing an RTC on Jessie. The RTC works fine, everytime, everyday, etc, until there is just one other access on the i2c to use such as a DAC, after which the RT...
by SteveA
Wed Jan 04, 2017 11:02 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Chronodot with rtc-ds1307 Read Error
Replies: 4
Views: 4182

Re: Chronodot with rtc-ds1307 Read Error

I have the same/similar problems and have spent many weeks trying to resolve it without success. I made a post at: https://www.raspberrypi.org/forums/viewtopic.php?f=33&t=169833&p=1090515#p1090515 which explains my problem. I have gone back on all of the forums posts I can find and see that ...
by SteveA
Sun Jan 01, 2017 7:03 pm
Forum: C/C++
Topic: Writing system date/time to I2C RTC
Replies: 0
Views: 1242

Writing system date/time to I2C RTC

Within my C program, the user needs to change the system date and time. It cannot be done in the shell in this instance as the user will not have access to a terminal command line. (for info, within my program I change the system time to that as wanted by the user by setting the time values in struc...
by SteveA
Fri Dec 23, 2016 7:13 pm
Forum: Advanced users
Topic: PWM on raspberry pi 3
Replies: 7
Views: 10239

Re: PWM on raspberry pi 3

I have exactly the same problem as per smufdwag, the original poster. The example PWM code as supplied with the bcm2835 lib and shown by smufdwag compiles and runs fine on my RPi2 and I can get a varying PWM signal on the 40W connector pin 12 (as seen on my scope and any connected devices). When tra...
by SteveA
Thu Dec 22, 2016 1:16 pm
Forum: Troubleshooting
Topic: Slow i2cdetect on one Pi 3 board only!
Replies: 8
Views: 7415

Re: Slow i2cdetect on one Pi 3 board only!

Of course you don't need to 'muck' about with what the kernel handles in normal times. Perhaps I did not make it clear that it was a method to get going again to be able to reset and continue with pinpointing the cause of the issue - as I said it was easier than repetively rebooting whilst chasing t...
by SteveA
Thu Dec 22, 2016 11:09 am
Forum: Troubleshooting
Topic: Slow i2cdetect on one Pi 3 board only!
Replies: 8
Views: 7415

Re: Slow i2cdetect on one Pi 3 board only!

I had the same problem and it plagued me for many weeks. This is what I found and did to cure it: Sometimes "sudo i2cdetect -y 1" was really slow and it took two or more seconds to test each address. This indicates that the I2C bus has got corrupted, held down or the drivers corrupted. I t...
by SteveA
Fri Jan 22, 2016 11:02 am
Forum: OpenVG
Topic: OpenVG program crashes randoml, code or faulty unit?
Replies: 17
Views: 8474

Re: OpenVG program crashes randoml, code or faulty unit?

Hello ajstarks,

I have cut sections out bit by bit and have done a test program of my project without my isolated ADC and input/output boards fitted. Could you please pm me to let me know where to email it. Thanks
by SteveA
Tue Jan 19, 2016 1:43 pm
Forum: OpenVG
Topic: OpenVG program crashes randoml, code or faulty unit?
Replies: 17
Views: 8474

Re: OpenVG program crashes randoml, code or faulty unit?

Further to the above I still have a problem where the graphics window gets corrupted after a long time, about 45 mins of continuous looping, which has only come to light this weekend due to the number and frequency of prompts being written to the screen. I am using Raspberry Pi 2, not overclocked, w...
by SteveA
Sun Nov 29, 2015 11:50 am
Forum: OpenVG
Topic: Erasing text leaves shadow/stop graphics swapping to desktop
Replies: 14
Views: 4266

Re: Erasing text leaves shadow/stop graphics swapping to des

Thanks to you all who answered and gave valuable advice and pointeres. The graphics layer now does not flip back to the desktop when the attached USB keyboard is touched after over 10mins of inactivety. I believe it is now fixed and I am sure that the firmware update I did was the cure for this. My ...
by SteveA
Wed Nov 25, 2015 4:18 pm
Forum: OpenVG
Topic: Erasing text leaves shadow/stop graphics swapping to desktop
Replies: 14
Views: 4266

Re: Erasing text leaves shadow/stop graphics swapping to des

Thanks ajstarks for the example of text updating. Is there also an example in 'c' somewhere, as I do not have the Go package.

Is there a link to learn the syntax of Go programming?

Thanks
by SteveA
Wed Nov 25, 2015 4:09 pm
Forum: OpenVG
Topic: Erasing text leaves shadow/stop graphics swapping to desktop
Replies: 14
Views: 4266

Re: Erasing text leaves shadow/stop graphics swapping to des

I have not been around for awhile, hence my delay in responding. Since my last post I have gone through my code from top to bottom and whilst I could find plenty of rubbish I needed to tidy up and streamline, I could not see a definitive issue so I then decided to update the Raspberry Pi and all its...
by SteveA
Mon Sep 21, 2015 9:04 pm
Forum: OpenVG
Topic: Erasing text leaves shadow/stop graphics swapping to desktop
Replies: 14
Views: 4266

Re: Erasing text leaves shadow/stop graphics swapping to des

I am on my way at moment and so will try the suggestions when I get back. Thanks

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