伽利略MRAA控制伺服的节点
我有一个英特尔伽利略我试图用Node.js的控制,但我跨越了几个问题来了。我正在使用的库有更改引脚的二进制和/或模拟值的示例,但没有关于控制伺服电机的具体内容。我目前的代码如下。伽利略MRAA控制伺服的节点
var B = 3975;
var mraa = require("mraa");
var servo = new mraa.Aio(1);//connects to the servo
事情是,我不知道如何控制伺服,MRAA的文档几乎不存在。有没有人在这里做过类似的事情,并能够提供帮助?
谢谢。
伺服系统通常使用PWM(脉宽调制)控制。您应该将伺服控制线连接到标有'〜'符号的数字引脚之一。该符号表示该引脚将生成PWM数据。然后谷歌你的伺服类型,以了解它接受的PWM参数。然后可以按照mraa PWM示例为PWM引脚设置合适的值。
PWM实施例对mraa(爱迪生但将工作于伽利略但期应当是62500)
mraa = require('mraa');
servo = new m.Pwm(3);//Pin 3
servo.enable(true);
servo.period_us(19000000) //PWM Period https://www.arduino.cc/en/Tutorial/SecretsOfArduinoPWM
servo.write(1);
sleep(1000);
servo.write(0);
sleep(1000);
servo.write(0.5);
要控制伺服,则发送给它的调制信号的脉冲宽度,这是这是一个信号定期的,即重复自己。每个周期,即信号点和其重复之间的时间,由两部分组成:开和关。 on是高电压(例如等于偏压),off是低电压(例如等于0 Volt)。期间有一个时间段是时间段,它的倒数是频率。开机时间与关机时间之间的比率称为占空比,占空比范围为0.0至1.0。伺服电机只旋转到达到与占空比对应的角度并停止。
什么这里之前是链接到mraa node.js的文档: https://iotdk.intel.com/docs/master/mraa/node/
和一张纸条说:mraa是一种低层次的框架,因此,如果这是您第一次使用伺服,我会建议你延迟使用mraa以后以及第一次使用CylonJS,用于控制使用CylonJS英特尔爱迪生的伺服这是相当类似于英特尔伽利略教程是: http://slideplayer.com/slide/7959041/ 这是一个非常好的例子,我在英特尔爱迪生套件之前跑了。
这就是说,一旦你使用本教程结束,想尝试在mraa node.js的伺服,这里是直到你按下Ctrl-C结束程序旋转伺服的教程。它在0开始占空比,将其增加到1,然后递减到0,然后再次循环。此代码是在 https://navinbhaskar.wordpress.com/2016/02/21/cc-on-intel-edisongalileo-part3-pwm/ C代码的翻译和我没有测试的翻译。
/*translation of C++ code at
https://navinbhaskar.wordpress.com/2016/02/21/cc-on-intel-edisongalileo-part3-pwm/
mraa node.js documentation at:
https://iotdk.intel.com/docs/master/mraa/node/
*/
"use strict";
const mraa = require("mraa");
const spawnSync = require('child_process').spawnSync;
const PWM_PIN = 5 ; /**< The pin where the LED is connected */
var keepRunning= false;
///** Signal handler used to stop this application cleanly */
/*
* Associate ctrl+c with our handler that clears the 'keepRunning'
* flag that allows us to stop the PWM when exiting
*/
process.on('SIGINT',() => {
keepRunning = false;
});
//Step 1: Initialize the mraa system
var result =mraa.init();
if(result == mraa.Result.SUCCESS)
console.log("mraa initialization succeded.");
else
console.log("mraa initializtion failed.")
/* Step2: Initialize D5 for PWM operation */
var pwm_interface = mraa.PWM;
var owner =true;
var chipid= 1;
pwm_interface.Pwm(PWM_PIN,owner,chipid);
/*
* Control the period with "mraa_pwm_period_us"
*
* +----------------+ +----------------+ |
* | | | | |
* | | | | |
* | | | | |
* | | | | |
* | | | | |
* | | | | |
* | | | | |
* | | | | |
* + +----------------+ +----------------+
* ^ ^
* | |
* |<---------- Period ------------->|
* | ^ |
* | | |
* |
* pwm_interface.period_us(5000);
*/
/* Step3: Set the period on the PWM pin */
const PWM_Period_in_microseconds=5000;
pwm_interface.period_us(PWM_Period_in_microseconds); // Set the period as 5000 us or 5ms
/* Step4: Enable the PWM pulse on the pin */
var pwm_enabling_result= pwm_interface.enable(true);
var delta = 0.05; /* Variation on the duty cycle */
var duty = 0.0; /* 0% duty cycle */
keepRunning = true;
const sleep_duration_in_Microsecond=50000;
while (keepRunning){
if (duty >= 1)
{
duty = 1; // Intensity of LED at highest
delta = -0.05; // Need to decrease the duty cycle
}
else if (duty <= 0)
{
duty = 0; // Intensity of LED at the lowest
delta = +0.05; // Need to increase the duty cycle
}
/*
* Control the duty cycle with "write"
* +------+ +------+
* | | | |
* | | | |
* | | | |
* | | | |
* | | | |
* | | | |
* | | | |
* | | | |
* + +----------------------------+ +---------------------------+
* ^ ^
* | |
* |<---->|
* ^
* |-----------------
* |
* pwm_interface.write(0.2);
*
*/
/* Step5: Use the function 'mraa_pwm_write' to set the duty cycle */
pwm_interface.write(duty);
/* Wait for some time */
var sleep = spawnSync('usleep', [sleep_duration_in_Microsecond]);
duty = duty + delta;
}
/* Step6: Stop the PWM when not required */
pwm_interface.enable(false);