我正在使用配置为接入点和服务器的 ESP8266 Thing Dev 板来存储来自温度传感器的数据。目标是使用 Android 应用程序访问这些数据,但目前使用的客户端是我运行 Chrome 的计算机。
传感器每 250 毫秒提供一次新的温度,这些温度被添加到字符串(JSON 格式)中。当客户端请求数据时,字符串结束(关闭 JSON 结构),并打印在服务器上。
客户端一次应该能够访问多达 2*50 个值。但是,每次发送请求时,要么只打印 2 个或 4 个值,要么页面不工作。
我的 Arduino 代码,对 arduino 使用 ESP8266 和 TMP102 库:
#include <ESP8266WiFi.h>
#include <Wire.h>
#include <Ticker.h>
#include "tmp102.h"
#define NB_MAX_TEMP 50
#define MAX_INPUT 20
const byte sensorAddress1 = 0x90; // ADD0 -> GND
const byte sensorAddress2 = 0x92; // ADD0 -> V+
tmp102 *thermometer1 = new tmp102(&Wire);
tmp102 *thermometer2 = new tmp102(&Wire);
// Timer
Ticker ticker;
bool flag = false;
// Wifi
const char WiFiAPPSK[] = "sparkfun"; // Wifi password
WiFiServer server(80);
int count = 0;
String s;
void setupWiFi()
{
WiFi.mode(WIFI_AP);
// Do a little work to get a unique-ish name. Append the
// last two bytes of the MAC (HEX'd) to "ThingDev-":
uint8_t mac[WL_MAC_ADDR_LENGTH];
WiFi.softAPmacAddress(mac);
String macID = String(mac[WL_MAC_ADDR_LENGTH - 2], HEX) +
String(mac[WL_MAC_ADDR_LENGTH - 1], HEX);
macID.toUpperCase();
String AP_NameString = "ThingDev-" + macID;
char AP_NameChar[AP_NameString.length() + 1];
memset(AP_NameChar, 0, AP_NameString.length() + 1);
for (int i = 0; i < AP_NameString.length(); i++)
AP_NameChar[i] = AP_NameString.charAt(i);
WiFi.softAP(AP_NameChar, WiFiAPPSK);
}
void timer_done()
{
flag = true;
}
void acquire()
{
int temp1 = 0, temp2 = 0;
if (thermometer1->readTemp(temp1))
{
// If we're reading pins, print out those values:
// first temp
s += String(temp1 * 0.0625);
}
s += ",";
if (thermometer2->readTemp(temp2))
{
// If we're reading pins, print out those values:
// second temp
s += String(temp2 * 0.0625);
}
return;
}
void setup()
{
Wire.begin(); // start the I2C library
Serial.begin(115200);
thermometer1->init(sensorAddress1);
thermometer2->init(sensorAddress2);
//Set default config.
thermometer1->writeConf(TMP102_DEFAULT_CONF);
thermometer2->writeConf(TMP102_DEFAULT_CONF);
setupWiFi();
server.begin();
// timer every 0.25s
ticker.attach(0.25, timer_done);
}
void loop()
{
// Check if a client has connected
WiFiClient client = server.available();
if (!client) {
return;
}
if (flag) {
flag = false;
int temp1 = 0, temp2 = 0;
if (count == 0) {
// prepare string
s = "HTTP/1.1 200 OK\r\n";
s += "Content-Type: text/html\r\n\r\n";
s += "{temp:[";
}
delay(1);
// add a measurement
s += "[";
acquire();
s += "],";
count += 1;
if (count == NB_MAX_TEMP) {
// Prevent the string to become infinite
count = 0;
s = s.substring(0, s.length() - 1);
s += "]};";
}
}
if (client.available() > 0) {
// Read the first line of the request
String req = client.readStringUntil('\r');
client.flush();
Serial.println(req);
if (req.indexOf("/read") != -1) {
// End the string
s.setCharAt(s.length() - 1, '\0');
s += "]};";
client.print(s);
Serial.println(s);
count = 0;
}
}
delay(1);
Serial.println("Client disconnected");
// The client will actually be disconnected
// when the function returns and 'client' object is detroyed
}
以及我在串行控制台上获得的示例(JSON 字符串与我在服务器页面上阅读的相同):
GET /read HTTP/1.1
HTTP/1.1 200 OK
Content-Type: text/html
{temp:[[24.00,24.56],[24.00,24.56];
Client disconnected
GET /favicon.ico HTTP/1.1
Client disconnected
GET /read HTTP/1.1
HTTP/1.1 200 OK
Content-Type: text/html
{temp:[[24.00,24.56];
Client disconnected
我究竟做错了什么 ?我在使用阻塞功能吗?/favicon.ico 请求是否会造成麻烦?
有关信息,我的代码的接入点部分和传感器部分已单独测试并按预期工作。
提前致谢。