ESP32+MQTT手机APP远程控制LED亮灭
2.1MQTT下载安装
官网—立即下载—windows—下载—解压—解压到D盘文件夹内(路径要去纯英文)
在bin文件夹内输入cmd打开命令符窗口,输入emqx start回车。
2.2MQTT服务器登录
打开网址https://doc.itprojects.cn/0006.zhishi.esp32/02.doc/index.html#/c05.mqtt,出现以下页面表示安装成功。登录默认的账户admin和密码public。
第一次登录会弹出一个提示修改密码,点击ok,设置新密码.
设置完成后可以在右上角的角色设置里面修改语言。
2.3手机连接MQTT点亮一颗LED
整体流程
1. esp32链接上wifi(注意与当前电脑链接到同一个局域网下,即同一个wifi路由器)
2. esp32上需要下载一个mqtt的库
3. 我们自己编写一个.py文件调用上面第2步的mqtt库,从而使用mqtt实现客户端的功能
4. 下mqtt调试器,远程开关LED。
第2步骤的mqtt库文件,名字叫做umqttsimple.py,内容如下,不要做任何修改复制到esp32即可。复制粘贴好后,保存的时候会弹出一个保存位置选项,此处选择esp就可以了。
import usocket as socket
import ustruct as struct
from ubinascii import hexlify
class MQTTException(Exception):
pass
class MQTTClient:
def __init__(
self,
client_id,
server,
port=0,
user=None,
password=None,
keepalive=0,
ssl=False,
ssl_params={},
):
if port == 0:
port = 8883 if ssl else 1883
self.client_id = client_id
self.sock = None
self.server = server
self.port = port
self.ssl = ssl
self.ssl_params = ssl_params
self.pid = 0
self.cb = None
self.user = user
self.pswd = password
self.keepalive = keepalive
self.lw_topic = None
self.lw_msg = None
self.lw_qos = 0
self.lw_retain = False
def _send_str(self, s):
self.sock.write(struct.pack("!H", len(s)))
self.sock.write(s)
def _recv_len(self):
n = 0
sh = 0
while 1:
b = self.sock.read(1)[0]
n |= (b & 0x7F) << sh
if not b & 0x80:
return n
sh += 7
def set_callback(self, f):
self.cb = f
def set_last_will(self, topic, msg, retain=False, qos=0):
assert 0 <= qos <= 2
assert topic
self.lw_topic = topic
self.lw_msg = msg
self.lw_qos = qos
self.lw_retain = retain
def connect(self, clean_session=True):
self.sock = socket.socket()
addr = socket.getaddrinfo(self.server, self.port)[0][-1]
self.sock.connect(addr)
if self.ssl:
import ussl
self.sock = ussl.wrap_socket(self.sock, **self.ssl_params)
premsg = bytearray(b"\x10\0\0\0\0\0")
msg = bytearray(b"\x04MQTT\x04\x02\0\0")
sz = 10 + 2 + len(self.client_id)
msg[6] = clean_session << 1
if self.user is not None:
sz += 2 + len(self.user) + 2 + len(self.pswd)
msg[6] |= 0xC0
if self.keepalive:
assert self.keepalive < 65536
msg[7] |= self.keepalive >> 8
msg[8] |= self.keepalive & 0x00FF
if self.lw_topic:
sz += 2 + len(self.lw_topic) + 2 + len(self.lw_msg)
msg[6] |= 0x4 | (self.lw_qos & 0x1) << 3 | (self.lw_qos & 0x2) << 3
msg[6] |= self.lw_retain << 5
i = 1
while sz > 0x7F:
premsg[i] = (sz & 0x7F) | 0x80
sz >>= 7
i += 1
premsg[i] = sz
self.sock.write(premsg, i + 2)
self.sock.write(msg)
# print(hex(len(msg)), hexlify(msg, ":"))
self._send_str(self.client_id)
if self.lw_topic:
self._send_str(self.lw_topic)
self._send_str(self.lw_msg)
if self.user is not None:
self._send_str(self.user)
self._send_str(self.pswd)
resp = self.sock.read(4)
assert resp[0] == 0x20 and resp[1] == 0x02
if resp[3] != 0:
raise MQTTException(resp[3])
return resp[2] & 1
def disconnect(self):
self.sock.write(b"\xe0\0")
self.sock.close()
def ping(self):
self.sock.write(b"\xc0\0")
def publish(self, topic, msg, retain=False, qos=0):
pkt = bytearray(b"\x30\0\0\0")
pkt[0] |= qos << 1 | retain
sz = 2 + len(topic) + len(msg)
if qos > 0:
sz += 2
assert sz < 2097152
i = 1
while sz > 0x7F:
pkt[i] = (sz & 0x7F) | 0x80
sz >>= 7
i += 1
pkt[i] = sz
# print(hex(len(pkt)), hexlify(pkt, ":"))
self.sock.write(pkt, i + 1)
self._send_str(topic)
if qos > 0:
self.pid += 1
pid = self.pid
struct.pack_into("!H", pkt, 0, pid)
self.sock.write(pkt, 2)
self.sock.write(msg)
if qos == 1:
while 1:
op = self.wait_msg()
if op == 0x40:
sz = self.sock.read(1)
assert sz == b"\x02"
rcv_pid = self.sock.read(2)
rcv_pid = rcv_pid[0] << 8 | rcv_pid[1]
if pid == rcv_pid:
return
elif qos == 2:
assert 0
def subscribe(self, topic, qos=0):
assert self.cb is not None, "Subscribe callback is not set"
pkt = bytearray(b"\x82\0\0\0")
self.pid += 1
struct.pack_into("!BH", pkt, 1, 2 + 2 + len(topic) + 1, self.pid)
# print(hex(len(pkt)), hexlify(pkt, ":"))
self.sock.write(pkt)
self._send_str(topic)
self.sock.write(qos.to_bytes(1, "little"))
while 1:
op = self.wait_msg()
if op == 0x90:
resp = self.sock.read(4)
# print(resp)
assert resp[1] == pkt[2] and resp[2] == pkt[3]
if resp[3] == 0x80:
raise MQTTException(resp[3])
return
# Wait for a single incoming MQTT message and process it.
# Subscribed messages are delivered to a callback previously
# set by .set_callback() method. Other (internal) MQTT
# messages processed internally.
def wait_msg(self):
res = self.sock.read(1)
self.sock.setblocking(True)
if res is None:
return None
if res == b"":
raise OSError(-1)
if res == b"\xd0": # PINGRESP
sz = self.sock.read(1)[0]
assert sz == 0
return None
op = res[0]
if op & 0xF0 != 0x30:
return op
sz = self._recv_len()
topic_len = self.sock.read(2)
topic_len = (topic_len[0] << 8) | topic_len[1]
topic = self.sock.read(topic_len)
sz -= topic_len + 2
if op & 6:
pid = self.sock.read(2)
pid = pid[0] << 8 | pid[1]
sz -= 2
msg = self.sock.read(sz)
self.cb(topic, msg)
if op & 6 == 2:
pkt = bytearray(b"\x40\x02\0\0")
struct.pack_into("!H", pkt, 2, pid)
self.sock.write(pkt)
elif op & 6 == 4:
assert 0
# Checks whether a pending message from server is available.
# If not, returns immediately with None. Otherwise, does
# the same processing as wait_msg.
def check_msg(self):
self.sock.setblocking(False)
return self.wait_msg()
新建一个esp32程序
import time
import network
from umqttsimple import MQTTClient
def do_connect():
wlan = network.WLAN(network.STA_IF)
wlan.active(True)
if not wlan.isconnected():
print('connecting to network...')
wlan.connect('name', 'password')#要连接的wifi名字和密码
i = 1
while not wlan.isconnected():
print("正在链接...{}".format(i))
i += 1
time.sleep(1)
print('network config:', wlan.ifconfig())
def sub_cb(topic, msg): # 回调函数,收到服务器消息后会调用这个函数
print(topic, msg)
# 1. 联网
do_connect()
# 2. 创建mqt
c = MQTTClient("umqtt_client", "192.168.1.54") # 建立一个MQTT客户端,前面是客户端的名字,后面是服务器的ip地址。
c.set_callback(sub_cb) # 设置回调函数
c.connect() # 建立连接
c.subscribe(b"ledctl") # 监控ledctl这个通道,接收控制命令
while True:
c.check_msg()
time.sleep(1)
运行后出现错误
按下esp开发板的EN按钮,重启一下就可以了。
打开cmd,输入ipconfig可以查看自己电脑的ip地址,因为服务是部署在自己电脑上的,所以此处的服务器就是自己电脑的ip地址。
查看自己电脑的端口号,输入netstat -na。
手机远程控制ESP32的LED亮灭
下载MQTT调试器
输入下面的信息
连接后就可以进行测试了
实验结果手机端显示发送成功,服务器收到消息,esp客户端没有反应,出现了之前的错误。
解决:
发消息有收到,但是发出消息没有发出。
可以看到前面的消息发出是没有的,后面解决后就有了。
2.4最终效果
就是这里的主题,之前没有写对,所以导致消息没有发出。