Raspberry Pi/Quick Reference

Revision as of 12:14, 26 March 2015

xset

Overview

xset allows you to control a few things, but the most common is the monitor states. You can manipulate, enable, or disable some features like:

• dpms energy star features
• monitor standby, suspend, off, or on
• screen blanking
• screen exposing
• activate/reset screen saver
• screen saver on/off

It should be noted that while this can blank the monitor, it does not tell the monitor to turn off it's backlight.

disable screen saver/blanking

a common issue with raspberry pis used in kiosk/monitor setups is the screen blanking/screen saver kicking in. You can disable them with the following commands:

~$xset s noblank
~$xset s noexpose
~$xset s off
~$xset dpms 0 0 0

check it by doing:

~$xset -q
 Keyboard Control:
  auto repeat:  on    key click percent:  0    LED mask:  00000000
  XKB indicators:
    00: Caps Lock:   off    01: Num Lock:    off    02: Scroll Lock: off
    03: Compose:     off    04: Kana:        off    05: Sleep:       off
    06: Suspend:     off    07: Mute:        off    08: Misc:        off
    09: Mail:        off    10: Charging:    off    11: Shift Lock:  off
    12: Group 2:     off    13: Mouse Keys:  off
  auto repeat delay:  500    repeat rate:  33
  auto repeating keys:  00ffffffdffffbbf
                        fadfffefffedffff
                        9fffffffffffffff
                        fff7ffffffffffff
  bell percent:  0    bell pitch:  400    bell duration:  100
Pointer Control:
  acceleration:  20/10    threshold:  10
Screen Saver:
  prefer blanking:  no    allow exposures:  no
  timeout:  0    cycle:  600
Colors:
  default colormap:  0x20    BlackPixel:  0x0    WhitePixel:  0xffff
Font Path:
  /usr/share/fonts/X11/misc,/usr/share/fonts/X11/Type1,built-ins
DPMS (Energy Star):
  Standby: 0    Suspend: 0    Off: 0
  DPMS is Enabled
  Monitor is On

Turn monitors on/off

You can use tvservice to turn the monitors on and off, however, turning them back on and displaying the signal is a bit tricky.

script to turn monitor on/off

#!/bin/bash -e
  
 # /usr/local/sbin/raspi-monitor
 # Script to enable and disable the HDMI signal of the Raspberry PI
 # Inspiration: http://www.raspberrypi.org/forums/viewtopic.php?t=16472&p=176258
  
 CMD="$1"
  
 function on {
     /opt/vc/bin/tvservice --preferred
  
     # Hack to enable virtual terminal nr 7 again:
     chvt 6
     chvt 7
 }
  
 function off {
     /opt/vc/bin/tvservice --off
 }
  
 function must_be_root {
     if [ $USER != root ]; then
         echo "ERROR: Script must be executed as the root user"
         exit 1
     fi
 }
  
 function main {
     must_be_root
     if [ "$CMD" == "on" ]; then
         on
     elif [ "$CMD" == "off" ]; then
         off
     else
         echo "Usage: $0 <on|off>"
         exit 1
     fi
     exit 0
 }
  
 main

Add to cron job

Add the following script as a cronjob file

~$ sudo nano /etc/cron.d/raspi-monitor-scheduler

# /etc/cron.d/raspi-monitor-scheduler
  
 # Enable the monitor every weekday morning at 7:00
 0 7 * * 1,2,3,4,5 root /usr/local/sbin/raspi-monitor on > /dev/null 2>&1
  
 # Disable the monitor every weekday evening at 19:30
 30 19 * * 1,2,3,4,5 root /usr/local/sbin/raspi-monitor off > /dev/null 2>&1

Make it executable

~$ sudo chmod +x /etc/cron.d/raspi-monitor-scheduler