softshut.py<\/strong> or whatever looks logic to you.<\/p>\n# Import the modules to send commands to the system and access GPIO pins\r\nfrom subprocess import call\r\nfrom time import sleep\r\nimport RPi.GPIO as gpio\r\n\r\n# Define a function to keep script running\r\ndef loop():\r\n raw_input()\r\n\r\n# Define a function to run when an interrupt is called\r\ndef shutdown(pin):\r\n sleep (0.1); # 100ms debounce delay\r\n if not gpio.input(13):\r\n # You might want to do something before shutting down the Pi\r\n # add these code lines here (see example line below)\r\n # call(['mpc', 'pause'], shell=False)\r\n call('halt', shell=False)\r\n\r\ngpio.setmode(gpio.BOARD) # Set pin numbering to board numbering\r\ngpio.setup(13, gpio.IN) # Set up pin 13 as an input\r\ngpio.setup(11, gpio.OUT, initial=gpio.HIGH) # Set up pin 11 as an output\r\n\r\ngpio.add_event_detect(13, gpio.FALLING, callback=shutdown) # Set up an interrupt to look for button presses\r\n\r\nloop() # Run the loop function to keep script running<\/pre>\nNext edit the file\u00a0\/etc\/rc.local<\/strong>, by adding the follow line:<\/p>\npython \/home\/pi\/softshut.py<\/pre>\nJust above the (last) line:<\/p>\n
exit 0<\/pre>\nIn some cases it might be necessary to add an ampersand, to run the script in the background, like so:<\/p>\n
python \/home\/pi\/softshut.py &<\/pre>\nHow does it work?<\/h3>\n
When the Raspberry Pi is powered up the rc.local<\/strong> file is executed and so is the softshut.py<\/strong> script. This script will only set the output pin (11) high on start-up and then “watch” for the input pin (13) to go low. When the input pin goes low the halt<\/em> command will nicely shutdown the Pi.<\/p>\nThat’s it.<\/p>\n
Connecting it to the Pi<\/h2>\n
Connector P2 will power the Raspberry Pi. You can use the USB connector for that or the 5V en GND pins on the GPIO header of the Pi.<\/p>\n
Next are the IO lines from P3.<\/p>\n
P3 pin 2 RA1 ----------- > --------- GPIO pin 13\r\n\r\nP3 pin 3 RA0 ----------- < --------- GPIO pin 11\r\n\r\nP3 pin 4 GND ----------------------- GPIO GND<\/pre>\n","protected":false},"excerpt":{"rendered":"The Raspberry Pi lacks a decent power ON\/OFF button. With a handful of cheap components a ATX style power-switch can be build. Schematics Main parts are a PIC microcontroller, a 5V relay, a push button and a LED.<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2,3],"tags":[19,16,18,20],"_links":{"self":[{"href":"http:\/\/www.bergrans.com\/site\/wp-json\/wp\/v2\/posts\/204"}],"collection":[{"href":"http:\/\/www.bergrans.com\/site\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.bergrans.com\/site\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.bergrans.com\/site\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"http:\/\/www.bergrans.com\/site\/wp-json\/wp\/v2\/comments?post=204"}],"version-history":[{"count":40,"href":"http:\/\/www.bergrans.com\/site\/wp-json\/wp\/v2\/posts\/204\/revisions"}],"predecessor-version":[{"id":256,"href":"http:\/\/www.bergrans.com\/site\/wp-json\/wp\/v2\/posts\/204\/revisions\/256"}],"wp:attachment":[{"href":"http:\/\/www.bergrans.com\/site\/wp-json\/wp\/v2\/media?parent=204"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.bergrans.com\/site\/wp-json\/wp\/v2\/categories?post=204"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.bergrans.com\/site\/wp-json\/wp\/v2\/tags?post=204"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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<\/a><\/p>\n