Articles, notes and random thoughts on Software Development and Technology
Per discussion here, if you have a v1.1 version of the Raspberry Pi 7″ touchscreen, you can vary the brightness by setting a value of 1 to 255 into the file /sys/class/backlight/rpi-backlight/brightness
Use sudo to echo values to a file, do:
sudo sh -c "echo 80 > /sys/class/backlight/rpi_backlight/brightness"
I have a 2.8 PiTFT which I’ve used on my Pi 1 and just set it up on a Pi 2. I tried to get Adafruit’s FreqShow working with the screen, and it would display, but was unresponsive to any touch inputs. I know touch was working in X Windows otherwise, and had ran through all the calibration tools in the PiTFT setup instructions, so something else was wrong.
Some Googling later, turns out the PiTFT and PyGame (used by FreqShow) works ok on Raspbian Wheezy (which I have on my Pi 1), but not on Jessie (which I have on my Pi 2).
Trick is to replace libsdl with the prior/older version from Jessie – a script to do the replacement is in the post linked about. Ran the script, and now FreqShow works on the PiTFT 2.8 great. Shame there’s no audio out as well, but a cool use for the small screen.
From this article, if you’re using one of the Wifi dongles on a Pi 1 or 2 (Pi3 has built in wifi), you can prevent the random dropouts during periods of inactivity by:
sudo nano /etc/modprobe.d/8192cu.conf
and then paste in and save this:
options 8192cu rtw_power_mgnt=0 rtw_enusbss=1 rtw_ips_mode=1
and then reboot.
Quick followup from last week’s post on setting up an onscreen keyboard. I couldn’t find a way of getting an onscreen keyboard, either matchbox-keyboard or florence, to respond on Raspbian’s logon screen. Rather than spend more time on investigating this, I just enabled the logon to desktop in raspi-config, and now logged on, either of the keyboards work as expected, perfectly well.
Florence seems to be the better of the two I tried. Once opened from the menu you can drag it around, or minimize it to a keyboard icon, so you can pop-it open as needed.
If I could get it to work from the logon screen too that would be awesome, but avoiding that issue and once you get to the desktop, it works great.