【零知ESP8266】教程：MESH 組網示例

ID:349555 · 發表于 2019-6-19 11:53

本帖最后由 roc2 于 2019-6-19 11:54 編輯

1、概述

MESH組網技術在IOT領域具有非常大的作用，應用非常廣泛，主流的無線技術從最開始的Zigbee，到藍牙，到這里的WIFI都實現了MESH組網技術。在這里使用零知開源平臺演示WIFI WESH組網的使用。

2、軟件和硬件

硬件使用零知-ESP8266；

軟件使用零知開發工具，自帶示例：

3、方法步驟

（1）先在零知開發工具中打開HelloMesh示例，或者復制下面的代碼到零知開發工具中：

/**********************************************************
* 文件: x.ino by 零知實驗室
* -^^- 零知開源，讓電子制作變得更簡單！ -^^-
* 時間: 2019/05/28 12:22
* 說明:
************************************************************/
#include <ESP8266WiFi.h>
#include <ESP8266WiFiMesh.h>
#include <TypeConversionFunctions.h>
#include <assert.h>
const char exampleMeshName[] PROGMEM = "MeshNode_";
const char exampleWiFiPassword[] PROGMEM = "123456789";//ChangeThisWiFiPassword_TODO
unsigned int requestNumber = 0;
unsigned int responseNumber = 0;
String manageRequest(const String &request, ESP8266WiFiMesh &meshInstance);
transmission_status_t manageResponse(const String &response, ESP8266WiFiMesh &meshInstance);
void networkFilter(int numberOfNetworks, ESP8266WiFiMesh &meshInstance);
/* Create the mesh node object */
ESP8266WiFiMesh meshNode = ESP8266WiFiMesh(manageRequest, manageResponse, networkFilter, FPSTR(exampleWiFiPassword), FPSTR(exampleMeshName), "", true);
/**
Callback for when other nodes send you a request
@param request The request string received from another node in the mesh
@param meshInstance The ESP8266WiFiMesh instance that called the function.
@returns The string to send back to the other node
*/
String manageRequest(const String &request, ESP8266WiFiMesh &meshInstance) {
// We do not store strings in flash (via F()) in this function.
// The reason is that the other node will be waiting for our response,
// so keeping the strings in RAM will give a (small) improvement in response time.
// Of course, it is advised to adjust this approach based on RAM requirements.
/* Print out received message */
Serial.print("Request received: ");
Serial.println(request);
/* return a string to send back */
return ("Hello world response #" + String(responseNumber++) + " from " + meshInstance.getMeshName() + meshInstance.getNodeID() + ".");
}
/**
Callback for when you get a response from other nodes
@param response The response string received from another node in the mesh
@param meshInstance The ESP8266WiFiMesh instance that called the function.
@returns The status code resulting from the response, as an int
*/
transmission_status_t manageResponse(const String &response, ESP8266WiFiMesh &meshInstance) {
transmission_status_t statusCode = TS_TRANSMISSION_COMPLETE;
/* Print out received message */
Serial.print(F("Request sent: "));
Serial.println(meshInstance.getMessage());
Serial.print(F("Response received: "));
Serial.println(response);
// Our last request got a response, so time to create a new request.
meshInstance.setMessage(String(F("Hello world request #")) + String(++requestNumber) + String(F(" from "))
+ meshInstance.getMeshName() + meshInstance.getNodeID() + String(F(".")));
// (void)meshInstance; // This is useful to remove a "unused parameter" compiler warning. Does nothing else.
return statusCode;
}
/**
Callback used to decide which networks to connect to once a WiFi scan has been completed.
@param numberOfNetworks The number of networks found in the WiFi scan.
@param meshInstance The ESP8266WiFiMesh instance that called the function.
*/
void networkFilter(int numberOfNetworks, ESP8266WiFiMesh &meshInstance) {
for (int networkIndex = 0; networkIndex < numberOfNetworks; ++networkIndex) {
String currentSSID = WiFi.SSID(networkIndex);
int meshNameIndex = currentSSID.indexOf(meshInstance.getMeshName());
/* Connect to any _suitable_ APs which contain meshInstance.getMeshName() */
if (meshNameIndex >= 0) {
uint64_t targetNodeID = stringToUint64(currentSSID.substring(meshNameIndex + meshInstance.getMeshName().length()));
if (targetNodeID < stringToUint64(meshInstance.getNodeID())) {
ESP8266WiFiMesh::connectionQueue.push_back(NetworkInfo(networkIndex));
}
}
}
}
void setup() {
// Prevents the flash memory from being worn out, see: https://github.com/esp8266/Arduino/issues/1054 .
// This will however delay node WiFi start-up by about 700 ms. The delay is 900 ms if we otherwise would have stored the WiFi network we want to connect to.
WiFi.persistent(false);
Serial.begin(115200);
delay(50); // Wait for Serial.
//yield(); // Use this if you don't want to wait for Serial.
// The WiFi.disconnect() ensures that the WiFi is working correctly. If this is not done before receiving WiFi connections,
// those WiFi connections will take a long time to make or sometimes will not work at all.
WiFi.disconnect();
Serial.println();
Serial.println();
Serial.println(F("Note that this library can use static IP:s for the nodes to speed up connection times.\n"
"Use the setStaticIP method as shown in this example to enable this.\n"
"Ensure that nodes connecting to the same AP have distinct static IP:s.\n"
"Also, remember to change the default mesh network password!\n\n"));
Serial.println(F("Setting up mesh node..."));
/* Initialise the mesh node */
meshNode.begin();
meshNode.activateAP(); // Each AP requires a separate server port.
// meshNode.setStaticIP(IPAddress(192, 168, 4, 22)); // Activate static IP mode to speed up connection times.
}
int32_t timeOfLastScan = -10000;
void loop() {
if (millis() - timeOfLastScan > 3000 // Give other nodes some time to connect between data transfers.
|| (WiFi.status() != WL_CONNECTED && millis() - timeOfLastScan > 2000)) { // Scan for networks with two second intervals when not already connected.
String request = String(F("Hello world request #")) + String(requestNumber) + String(F(" from ")) + meshNode.getMeshName() + meshNode.getNodeID() + String(F("."));
meshNode.attemptTransmission(request, false);
timeOfLastScan = millis();
// One way to check how attemptTransmission worked out
if (ESP8266WiFiMesh::latestTransmissionSuccessful()) {
Serial.println(F("Transmission successful."));
}
// Another way to check how attemptTransmission worked out
if (ESP8266WiFiMesh::latestTransmissionOutcomes.empty()) {
Serial.println(F("No mesh AP found."));
} else {
for (TransmissionResult &transmissionResult : ESP8266WiFiMesh::latestTransmissionOutcomes) {
if (transmissionResult.transmissionStatus == TS_TRANSMISSION_FAILED) {
Serial.println(String(F("Transmission failed to mesh AP ")) + transmissionResult.SSID);
} else if (transmissionResult.transmissionStatus == TS_CONNECTION_FAILED) {
Serial.println(String(F("Connection failed to mesh AP ")) + transmissionResult.SSID);
} else if (transmissionResult.transmissionStatus == TS_TRANSMISSION_COMPLETE) {
// No need to do anything, transmission was successful.
} else {
Serial.println(String(F("Invalid transmission status for ")) + transmissionResult.SSID + String(F("!")));
assert(F("Invalid transmission status returned from responseHandler!") && false);
}
}
}
Serial.println();
} else {
/* Accept any incoming connections */
meshNode.acceptRequest();
}
}

復制代碼

（2）驗證并上傳上述代碼到零知-ESP8266開發板；

（3）測試：分別把上述代碼上傳到兩個零知-ESP8266開發板，然后分別連接兩個板子的串口調試窗口，然后就可以看到兩個節點數據傳輸信息了：

注意：密碼修改時候字符要大于8個字符，不然會一直提示No mesh AP found。

更多詳細資料可到零知實驗室官網免費獲取。

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【零知ESP8266】教程：MESH 組網示例

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