温度传感器(DS18B20)
=====================

.. figure:: /_static/products/ledong-module/static/图片/ds18b20.png
	:width: 55%
	:align: center

概述
--------------------
基于DS18B20数字温度传感器,用于检测环境温度。


技术参数
-------------------

工作电压： VCC 3.3V -5V

模块尺寸：24*48mm

固定安装：2个兼容塑料积木通孔

温度：-55--125℃



引脚定义
-------------------

=====  ======== 
引脚    定义   
=====  ========  
GND    地  
VCC    电源  
DI     数字输出
NC     空
=====  ======== 



示例程序
-------------------

**间隔一秒打印温度信息**

.. code-block:: python

    from mpython import *

    from machine import Timer

    import onewire

    import ds18x20

    _ds18x20_list = []

    tim13 = Timer(13)

    def timer13_tick(_):
        for p in _ds18x20_list:
            try:
                eval("ds_" + p + ".convert_temp()")
                for rom in eval("roms_" + p):
                    t = eval("ds_" + p).read_temp(rom)
                    eval("set_ds_value_" + p + "(" + str(t) + ")")
                    break
            except: pass

    tim13.init(period=1000, mode=Timer.PERIODIC, callback=timer13_tick)

    import time

    def set_ds_value_0(_t):
        global _ds18x20_value_0
        _ds18x20_value_0 = _t

    ow_0 = onewire.OneWire(Pin(Pin.P0))
    ds_0 = ds18x20.DS18X20(ow_0)
    roms_0 = ds_0.scan()
    _ds18x20_value_0 = 0
    _ds18x20_list.append(str(0))
    while True:
        print(_ds18x20_value_0)
        time.sleep(1)

.. figure:: /_static/products/ledong-module/static/examples/ds18b20.png
	:align: center