[英]GPIO over Raspberry Pi 3 model B using Node.js
我正在嘗試使用樹莓派3 B型來閃爍LED,
我已經在我的機器上安裝了所有必需的模塊,即npm,nodejs,pi-gpio(修復了微小的更改以檢測gpio)
代碼是:
var gpio = require("pi-gpio");
gpio.open(16, "output", function(err) {
gpio.write(16, 1, function() {
gpio.close(16);
});
});
//reading the data on the pin i.e pin : 16
gpio.open(16, "output", function (err) {
gpio.read(16, function (err, value) {
console.log("Data is "+ value);
gpio.close(16);
});
});
但是上面的代碼在運行時會引發錯誤,
節點app.js
錯誤: 嘗試打開16針時出錯gpio-admin:無法將數據刷新到/ sys / class / gpio / export:設備或資源繁忙
提前致謝
我可以在其中看到電路圖和代碼的任何鏈接。
關注:我不想更改平台,即node.js
我正在使用的pi-gpio是: https : //github.com/rakeshpai/pi-gpio
pi-gpio
只是在后台寫入GPIO設備,因此您可以跳過node.js
和pi-gpio
並手動執行相同操作以進行測試。
例:
gpio.open(16, ...
# is the same as writing in terminal:
echo 16 > /sys/class/gpio/export
和
... "output" ...
# is the same as writing in terminal:
echo "out" > /sys/class/gpio/gpio16/direction
等等
首先,嘗試重新啟動Pi,看看是否可以解決此問題。
如果那沒有幫助,請嘗試以根用戶身份手動關閉/取消導出該引腳,然后重新運行腳本。
# unexport the pin as root in case something's holding on to it
sudo echo 16 > /sys/class/gpio/unexport
以下命令基本上構成了pi-gpio
API。 這些行就是您要在Shell腳本中放置以控制GPIO的內容。 首先按照我編寫它們的順序在沒有sudo的情況下對其進行測試,如果它們不起作用,請嘗試使用sudo。 如果它們仍然不起作用,我認為您在布線/硬件方面有問題,或者需要在其他地方更改某些系統設置。
# unexport the pin
sudo echo 16 > /sys/class/gpio/unexport
# export it again
sudo echo 16 > /sys/class/gpio/export
# make it an output
sudo echo "out" > /sys/class/gpio/gpio16/direction
# write a HIGH - is the LED on now?
sudo echo 1 > /sys/class/gpio/gpio16/value
# read the value of the pin - is it 1 after writing a 1 to the pin?
cat /sys/class/gpio/gpio16/value
# write a LOW - did it turn off?
sudo echo 0 > /sys/class/gpio/gpio16/value
由於pi-gpio已經修復了舊的和新的sysPath(issue# https://github.com/rakeshpai/pi-gpio )
但這取決於quick2wire-gpio-admin lib。
在quick2wire-gpio-admin中需要很小的修復
git clone https://github.com/quick2wire/quick2wire-gpio-admin.git
cd quick2wire-gpio-admin
src/gpio-admin.c
具有
int size = snprintf(path, PATH_MAX, "/sys/devices/virtual/gpio/gpio%u/%s", pin, filename);
用。。。來代替 :
int size = snprintf(path, PATH_MAX, GPIO_CLASS_PATH "gpio%u/%s", pin, filename);
然后轉到cd quick2wire-gpio-admin
目錄
然后sudo make uninstall
並
sudo make install
然后運行正常。
的代碼如下:(文件名:blinking12.js)
var gpio = require("pi-gpio");
var intervalId;
var durationId;
var gpioPin = 12;
gpio.open(gpioPin, "output", function (err) {
var on =1 ;
console.log("GPIO pin "+gpioPin+" is open toggling LED every 100mS for 10s");
intervalId = setInterval( function () {
gpio.write(gpioPin, on, function () {
on = (on + 1)% 2;
});
}, 100);
});
durationId = setTimeout (function () {
clearInterval(intervalId);
clearTimeout(durationId);
console.log('10 seconds blinking completed');
gpio.write(gpioPin, 0, function () {
gpio.close(gpioPin);
//process.exit(0);
});
}, 10000);
運行代碼:
node blinking12.js
在我的機器上輸出:
GPIO pin 12 is open toggling LED every 100mS for 10s
10 seconds blinking completed
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