Links to all my notes (includes mini-projects and source code etc)
(+) 0001 How do I change the Pi System partition size ?
(+) 0100 Device tree settings
(+) 0201 Power over Ethernet - (PoE)
(+) 0202 Solar Power - (with WiFi)
(+) 0203 Power Bank pass through
(+) 0400 Accessing the SDHC card system image
(+) 0401 Accessing PC shares from the Pi
(+) 0402 Installing samba - (the Pi as a Network Share on your PC)
(+) 0900 Can this approach be scaled up to a PC UPS ?
(+) 1001 Pandora Spotify on the Pi
(+) 1002 Playing movies on the Pi
(+) 1003 Getting VGA from the HDMI socket
(+) 1004 Using the RCA socket
(+) 1005 Using the Pi RS232 serial links
(+) 1006 Using the GPIO pins
(-) 1007 Controlling the Pi Zero ACT LED
The Pi Zero has one LED, led0 (labeled 'ACT' on the board). The LED drive is 'inverted' so, when it defaults to 'brightness 0' this turns the LED 'on' ! The system software issues a 'trggger' that sets 'brightness 1' (for a short time) during 'disk activity' (i..e during SDHC card access) which turns the LED off. Needles to say, when running from batteries, wasting XmA on an almost permanently 'on' LED is a luxury we can't afford :-) You can control, the LED from a CLI / script by removing the 'disk activity' trigger and then 'manually' turning it on/off as follows :- # Set the Pi Zero ACT LED trigger to 'none'. echo none | sudo tee /sys/class/leds/led0/trigger # Turn off the Pi Zero ACT LED. echo 1 | sudo tee /sys/class/leds/led0/brightness # Turn on the Pi Zero ACT LED. echo 0 | sudo tee /sys/class/leds/led0/brightness To permanently disable the LED, add the following lines to your Pi's /boot/config.txt file and reboot: # Disable the ACT LED on the Pi Zero. dtparam=act_led_trigger=none dtparam=act_led_activelow=on
This note last modified: 4th Jun 2017 15:27.