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<\/a><\/p>\nIts always on, not really good for the back-light and energy consumption.<\/p>\n
So I got the idea of plugging a PIR sensor to wake up the screen when someone approach it.<\/p>\n
Let’s give a try, with a basic wiring, and this sketch to emulate keyboard thanks to it’s USB HID, the Arduino Micro Pro is a must.<\/p>\n Updated 05-01-2017:<\/p>\n I have an always on net-book for weather forecast (yeah, when paragliding, you need the most up to date forecast) It basically displays a full screen custom web-page with time and date and weather. Its always on, not really good … Continue reading <\/a>Take an Arduino Micro Pro<\/a> (4\u20ac for the Chinese version), a PIR sensor<\/a>\u00a0(2\u20ac), a Hammond case <\/a>(1\u20ac) and an USB A male from scrap (0\u20ac).<\/p>\n<\/a><\/p>\n<\/a><\/p>\n\n
#include <Keyboard.h>\r\n\r\n#define SENSOR_PIN 10 \/\/ Senor state input pin\r\n#define RX_LED_PIN 17\u00a0 \/\/ The RX LED has a defined Arduino pin\r\nstatic bool sensor_previous_state = false;\r\n\r\nvoid setup()\r\n{\r\n\u00a0 pinMode(SENSOR_PIN, INPUT);\u00a0 \/\/ PIR sensor pin as input\r\n\u00a0 pinMode(RX_LED_PIN, OUTPUT);\u00a0\u00a0\u00a0\u00a0 \/\/\u00a0 RX LED as an output\r\n\u00a0 digitalWrite(RX_LED_PIN, HIGH);\u00a0 \/\/\u00a0 RX LED off\r\n\u00a0 TXLED0;\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ switch on TX green to show init\/powered up (only available by macro)\r\n\u00a0 sensor_previous_state = digitalRead(SENSOR_PIN); \/\/ get sensor initial state (can be already true)\r\n}\r\n\r\nvoid loop()\r\n{\r\n\u00a0 bool sensor_current_state = digitalRead(SENSOR_PIN);\r\n\u00a0 if ( sensor_previous_state == false\u00a0\u00a0 \/\/ looping until we detect a rising edge\r\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 && sensor_current_state == true) {\/\/ when sensor state is trigged, it takes about 20 sec to recover\r\n\u00a0\u00a0\u00a0 digitalWrite(RX_LED_PIN, LOW);\u00a0\u00a0 \/\/ set the LED on\r\n\u00a0\u00a0\u00a0 USBDevice.wakeupHost();\r\n\u00a0\u00a0\u00a0 Keyboard.press( KEY_CAPS_LOCK );\r\n\u00a0\u00a0\u00a0 Keyboard.release( KEY_CAPS_LOCK );\r\n\u00a0\u00a0\u00a0 TXLED0;\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ great hackery in this: we have to force down the TXLED\r\n\u00a0\u00a0\u00a0 delay(1000);\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ wait a bit for the led\r\n\u00a0 } else {\r\n\u00a0\u00a0\u00a0 digitalWrite(RX_LED_PIN, HIGH);\u00a0\u00a0\u00a0 \/\/ set the LED off\r\n\u00a0\u00a0\u00a0 TXLED0;\r\n\u00a0 }\r\n\u00a0 sensor_previous_state = sensor_current_state;\r\n}<\/pre>\n<\/a><\/a><\/a>2017 update: lightguide for green and orange LEDs:<\/div>\n<\/a><\/div>\n<\/div>\n