零知增强板-WIFI网络图像传输 OV2460 ESP8266 SPI传输

本次实验主要使用零知增强板+ESP8266无线模块+OV2640，将摄像头数据通过WIFI传输到上位机进行显示，程序有很多地方需要优化，这里仅仅抛砖引玉，提供一个网络传输图像的大体思路。

一、硬件连接：

ESP8266与零知增强板连接如下：（参照之前ESP8266 SPI方式传输文章）

零知增强板与OV2640/OV7670摄像头连接：零知增强板上自带摄像头接口，请直接接入摄像头模块，这里使用的是OV2640摄像头进行试验。

二、软件代码编写

（1）零知平台代码，本次实验使用UDP进行传输，零知板上的ESP8266作为UDP客户端与上位机进行通信，主要代码如下：


												
	/*
	WiFiSPI example: esp8266连接AP，UDP传输数据
	 
	电路连接：
	   1. On ESP8266 must be running (flashed) WiFiSPIESP application.
	     
	   2. Connect the Arduino to the following pins on the esp8266:
	 
	            ESP8266         |
	    GPIO    NodeMCU   Name  |   Lingzhi Enhanced Board
	   ===================================
	     15       D8       SS   |   53
	     13       D7      MOSI  |   51
	     12       D6      MISO  |   50
	     14       D5      SCK   |   52
	*/
	 
	#include "WiFiSpi.h"
	#include "WiFiSpiUdp.h" 
	 
	#include "camera.h"
	 
	#include <fsmc_lcd.h>
	 
	CAMERA_DCMI_INTERFACE camera;
	 
	#ifdef JPEG_OUTPUT_MODE
	uint32_t jpeg_buf[jpeg_buf_size];        //JPEG数据缓存buf
	extern volatile uint8_t jpeg_data_ok;
	extern volatile uint32_t jpeg_data_len;
	#endif
	 
	unsigned int localPort = 8081;
	 
	#define        ssid                "lingzhilab"//换成自己的wifi热点
	#define        password        "lingzhilab.com"
	 
	char udpServerIP[] = "192.168.0.126";
	int serverPort = 8081;
	 
	#define PACKET_SIZE 512
	byte packetBuffer[PACKET_SIZE];
	 
	const int UDP_TIMEOUT = 2000;
	 
	WiFiSpiUdp udpClient;
	 
	WiFiSpiClient client;
	 
	uint8_t connect_server_flag = 0;
	 
	void setup()
	{
	  // initialize serial for debugging
	  Serial.begin(9600);
	  Serial3.begin(460800);//camera data
	  // initialize the ESP module
	  WiFiSpi.init();
	 
	  // 检查是否连接了运行SPIWifi程序的8266模块
	  if (WiFiSpi.status() == WL_NO_SHIELD) {
	    Serial.println("WiFi shield not present");
	    // don't continue
	    while (true);
	  }
	 
	  int status = WL_IDLE_STATUS;
	  // attempt to connect to WiFi network
	  while (status != WL_CONNECTED) {
	    Serial.print("Attempting to connect to WPA SSID: ");
	    Serial.println(ssid);
	    // Connect to WPA/WPA2 network
	    status = WiFiSpi.begin(ssid, password);
	  }
	 
	  // you're connected now, so print out the data
	  Serial.println("You're connected to the network");
	   
	  udpClient.begin(localPort);
	   
	  //camera begin
	        camera.begin(OV2640_DEVICE_ID);
	 
	#ifdef JPEG_OUTPUT_MODE
	        camera.setOutSize(800,600);
	        camera.startCapture((uint32_t)&jpeg_buf);
	#endif
	}
	 
	void loop()
	{
	  sendPacket(udpServerIP); // send an packet to server
	 
	  // wait ten seconds before asking for the time again
	  //delay(100);
	}
	 
	int i;
	uint8_t *p;
	 
	// send an packet to server 
	void sendPacket(char *server)
	{
	        //send camera data process
	        {
	                if(jpeg_data_ok==1)        //
	                {
	                        p=(uint8_t*)jpeg_buf;
	 
	//                        Serial.println("send one frame data...");
	                         
	                        int times = jpeg_data_len*4/1024;
	                        int retlen = jpeg_data_len*4 - 1024*times;
	                        int x = 0;
	                        for(x=0; x<times; x++)
	                        {
	                                udpClient.beginPacket(server, serverPort);
	                                udpClient.write(p+1024*x,1024);
	                                udpClient.endPacket();
	                        }
	                         
	                        udpClient.beginPacket(server, serverPort);
	                        udpClient.write(p+1024*x,retlen);
	                        udpClient.endPacket();
	                         
	 
	                        jpeg_data_ok=2;        //
	                }
	        }
	}

上述代码中，需要替换自己的WIFI热点名字和密码。

上位机代码编写：

参考这里，源码开放下载，根据自己需求进行更改即可：
源代码:camera-capture-v2.7z(点击下载)
可执行程序:camera上位机调试.7z(点击下载)

三、测试验证

将模块按照步骤1正确连线后，将代码验证后上传到零知平台，然后就可以在上位机通过WIFI查看摄像头数据了，这里仅传输JPG格式图像，数据量较少，有时候会出现图像不完整的情况，因此需要一定的优化已达到更好的效果。

完整工程和库

wifi-spi-transfer.7z(点击下载)