Raspberry Pi Forums

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Superficially, my Raspberry Pi 4 seems to be running normal. But: - the green LED flashes way less than what I experience with other Pis (e.g. when there's definite write activity it does not flash), - the red LED stays off all the time, - there are no underpower warnings, but - a USB DVB-T dongle w...

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(that's what hacking is all about). And I could not stop myself from hacking. Thank you for your code. I challenged myself to continue with my pythonic approach and hacked together two simple scripts: simpletouch.py can be used to toggle the screen off and on by touch. There is no specific region w...

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Dougie, you are interrupting my python eventures. : )

The program does exactly what I need. It may need some milliseconds for debouncing but that's not an issue. Thank you for your help!

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Looks promising: > pip3 install evdev [snip] > python3 master!? Python 3.7.3 (default, Dec 20 2019, 18:57:59) [GCC 8.3.0] on linux Type "help", "copyright", "credits" or "license" for more information. >>> from evdev import InputDevice, categorize, ecodes >>> ...

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Do you mean you want "touch off, touch back on"? Yes! Knowing the screen state on shell level wouldn't be an issue. I can either read the brightness from /sys/class/backlight/rpi_backlight/brightness or the screen state from /sys/class/backlight/rpi_backlight/bl_power. There just seems to...

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I don't want to be ungrateful but am afraid the program does not do what I need. As a screensaver where one can set the maximum 'on' time when there is no input it may be useful but it cannot be used to simply toggle between on and off. When you set the time value to 60, touching the screen does not...

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DougieLawson wrote: ↑
Sat Jun 06, 2020 9:14 pm
I've improved the docs for my C program and added a missing piece.

Thanks you a lot. I'll try it out and report back.

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DarkElvenAngel wrote: ↑
Sat Jun 06, 2020 7:22 pm
Almost like a light switch?

Yes. Additionally, I'd like to keep the capability to turn the backlight/screen on or off by command. It seems Dougie put something together already. Thank you for your offer.

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No hurry. I highly appreciate your involvement in this community. If I knew any C I would cobble something together from your code myself.

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https://github.com/DougieLawson/backlight_dimmer does what you want. Now that I looked at it and run it I understand better what it does. It is similar to a screensaver where I set the time the screen stays on until it fades. The on-duration will be extended when a touch event is registered. It is ...

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Thank you for your reply! In my research I already came across your solution. Is it possible to run it indefinitely without a fixed delay and use it just to toggle display states? Well, I'll compile it and see for myself. This is the simple shell script I put together that would be called (option -t...

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Hi!

I know how to set brightness and turn the screen on and off from the command line. I want to toggle the screen between on and off via touch. Is there a better way to intercept touch events than using evtest in an endless loop?

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is it possible to tell the wlan interface to change the channel while it is connected to 5G band? Thanks for the suggestion but I don't think changing the channel would solve the original issue. I also think one has to select the channel the access Point is broadcasting on. The issue is twofold. It...

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Whitelisting the desired MAC, blacklisting the unwanted MAC of the AP and limiting the frequencies didn't help. Every once in a while the Raspberry ends up in the 5 GHz network. : (

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if freq_list =... is not working, maybe scan_freq =... to only scan the given frequencies. or non_pref_chan =... to define non prefered channels in multi band operation It wasn't working- I have the suspicion that the access point's steering is overriding the client's settings (which shouldn't happ...

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Thanks, I'll give it a shot.

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Paul Hutch wrote: ↑
Tue Jan 07, 2020 1:02 pm
You can use the freq_list parameter in wpa_supplicant.conf to limit what frequency/channels the Pi will connect to.

Thanks, but I trying that already (see above). It is not working. When I check, it initially connects to 34:81:C4:XX:XX:XX but soon switches to 34:81:C4:XX:XX:XY.

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is your 5Ghz/2.4GHz AP a DIY one? [...] you also can give both bands a different SSID name e.g. abc for the 2.4GHz band and abc-5g for the 5GHz band. so you can choose the bands by name, when you connect a device. Thanks for the remark. The access point is a widely used commercial cable router. Als...

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mattmiller wrote: ↑
Mon Jan 06, 2020 8:09 pm
One solution might be to buy a separate 2.4GHz dongle and just completely disable the internal

One solution when you can't unlock your house's back door is to add another one with a working lock. : )

Edit: No snarkyness intended.

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Try setting display and resolution settings in /boot/config.txt like this:

Code: Select all

hdmi_force_hotplug=1
hdmi_group=2 
hdmi_mode=16

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I would use Node RED, the Serial-In node and Node RED's dashboard. You can create flows for visualization and processing/storage.

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I don't know why but it seems two Raspberry Pis on my network (a 4b and a 3b) don't see each other when they are connected to different frequency bands on the same access point. In other words, it seems as if the access point wouldn't route between devices on different bands. On the other hand, I ca...

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Thank you for your help. I solved my issue. The reason why the camera wasn't found was that the /boot/config.txt entry to activate the camera was made in the wrong file. The partition the Pi booted from wasn't mounted as /boot but rather a clone of the boot partition on my USB3-connected SSD. I fixe...

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HermannSW wrote: ↑
Mon Oct 21, 2019 8:14 pm
What is the output of "vcgencmd get_camera"?

supported=0 detected=0

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Thanks for the response but I went through all the usual troubleshooting steps already. I have reached the stage where I wonder if it is a firmware problem.

Search found 187 matches

RPI 4, no red LED

Re: How to toggle screen by touch?

Re: How to toggle screen by touch?

Re: How to toggle screen by touch?

Re: How to toggle screen by touch?

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Re: How to toggle screen by touch?

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Re: How to toggle screen by touch?

How to toggle screen by touch?

Re: Odd routing, cannot force 4b Pi to 2.4 GHz wifi (wpa_supplicant)

Re: Odd routing, cannot force 4b Pi to 2.4 GHz wifi (wpa_supplicant)

Re: Odd routing, cannot force 4b Pi to 2.4 GHz wifi (wpa_supplicant)

Re: Odd routing, cannot force 4b Pi to 2.4 GHz wifi (wpa_supplicant)

Re: Odd routing, cannot force 4b Pi to 2.4 GHz wifi (wpa_supplicant)

Re: Odd routing, cannot force 4b Pi to 2.4 GHz wifi (wpa_supplicant)

Re: Odd routing, cannot force 4b Pi to 2.4 GHz wifi (wpa_supplicant)

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Odd routing, cannot force 4b Pi to 2.4 GHz wifi (wpa_supplicant)

Re: Check camera board on RPI4 [SOLVED]

Re: Check camera board on RPI4

Re: Check camera board on RPI4