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In our previous guide, we have shown that we can trigger ESP32 (with Arduino IDE) to send message to IBM Watson IoT in Presence of a Particular Samsung Galaxy Smartwatch. That process involves BLE and WiFi. In our one series of articles on Samsung Smartwatch as Proximity Switch, we triggered a local event, such as control of a LED. In our other series of articles, we used the IBM Watson IoT Widgets. A natural question arises: can we can make the ESP32 to trigger events on IBM Watson IoT when a particular Samsung Smartwatch will come closer to it so that we will get the status of the smartwatch, such as closer or far away? The screenshot will answer.
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IBM Watson IoT widgets or cards can be customized with images and CSS. We need one of the default widget for this project. This guide involves a piece of code which is improved version from the previous guide. This is the code :
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#include "BLEDevice.h" #include <WiFi.h> #include <WiFiMulti.h> #include <HTTPClient.h> #include <base64.h> #define USE_SERIAL Serial const char* ssid = "your-hotspot"; const char* password = "password-of-hotspot"; #define ORG "paste-it-here" #define DEVICE_TYPE "DevBoard" //change #define DEVICE_ID "ESP32" // change #define TOKEN "your-token" #define EVENT "myEvent" // example // <------- CHANGE PARAMETERS ABOVE THIS LINE ------------> String urlPath = "/api/v0002/device/types/" DEVICE_TYPE "/devices/" DEVICE_ID "/events/" EVENT; String urlHost = ORG ".messaging.internetofthings.ibmcloud.com"; int urlPort = 8883; String authHeader; static BLEAddress *pServerAddress; BLEScan* pBLEScan; BLEClient* pClient; bool deviceFound = false; bool LEDoff = false; bool BotonOff = false; String knownAddresses[] = { "e0:a1:07:b7:0b:95"}; // change the MAC unsigned long entry; static void notifyCallback( BLERemoteCharacteristic* pBLERemoteCharacteristic, uint8_t* pData, size_t length, bool isNotify) { Serial.print("Notify callback for characteristic "); Serial.print(pBLERemoteCharacteristic->getUUID().toString().c_str()); Serial.print(" of data length "); Serial.println(length); } class MyAdvertisedDeviceCallbacks: public BLEAdvertisedDeviceCallbacks { void onResult(BLEAdvertisedDevice Device){ // show the MAC of other BLE devices //Serial.print("BLE Advertised Device found: "); //Serial.println(Device.toString().c_str()); pServerAddress = new BLEAddress(Device.getAddress()); bool known = false; bool Master = false; for (int i = 0; i < (sizeof(knownAddresses) / sizeof(knownAddresses[0])); i++) { if (strcmp(pServerAddress->toString().c_str(), knownAddresses[i].c_str()) == 0) known = true; } if (known) { Serial.print("Our device found!"); Serial.print("Device distance:"); Serial.println(Device.getRSSI()); // adjust the value. -85 is medium distance // -60 is closer than -85 if (Device.getRSSI() > -85) { deviceFound = true; } else { deviceFound = false; } Device.getScan()->stop(); delay(100); } } }; void setup() { Serial.begin(115200); BLEDevice::init(""); pClient = BLEDevice::createClient(); pBLEScan = BLEDevice::getScan(); pBLEScan->setAdvertisedDeviceCallbacks(new MyAdvertisedDeviceCallbacks()); pBLEScan->setActiveScan(true); initWifi(); authHeader = "Authorization: Basic " + base64::encode("use-token-auth:" TOKEN) + "\r\n"; Serial.println("Done"); } void Bluetooth() { Serial.println(); Serial.println("BLE Scan restarted....."); deviceFound = false; BLEScanResults scanResults = pBLEScan->start(5); if (deviceFound) { Serial.println("Found"); doWiFiClientSecure(); delay(10000); } else{ Serial.println("Device is not closer"); doWiFiClientLost(); } } void loop() { Bluetooth(); } void doWiFiClientSecure() { WiFiClientSecure client; Serial.print("connect: "); Serial.println(urlHost); while ( ! client.connect(urlHost.c_str(), urlPort)) { Serial.print("."); } Serial.println("Connected"); String postData = String("{ \"d\": {\"Our device found!\": \"") + millis()/1000 + "\"} }"; String msg = "POST " + urlPath + " HTTP/1.1\r\n" "Host: " + urlHost + "\r\n" "" + authHeader + "" "Content-Type: application/json\r\n" "Content-Length: " + postData.length() + "\r\n" "\r\n" + postData; client.print(msg); Serial.print(msg); Serial.print("\n*** Request sent, receiving response..."); while (!!!client.available()) { delay(50); Serial.print("."); } Serial.println(); Serial.println("Got response"); while(client.available()){ Serial.write(client.read()); } Serial.println(); Serial.println("closing connection"); client.stop(); } void doWiFiClientLost() { WiFiClientSecure client; Serial.print("connect: "); Serial.println(urlHost); while ( ! client.connect(urlHost.c_str(), urlPort)) { Serial.print("."); } Serial.println("Connected"); String postData = String("{ \"d\": {\"Our device is away!\": \"") + millis()/1000 + "\"} }"; String msg = "POST " + urlPath + " HTTP/1.1\r\n" "Host: " + urlHost + "\r\n" "" + authHeader + "" "Content-Type: application/json\r\n" "Content-Length: " + postData.length() + "\r\n" "\r\n" + postData; client.print(msg); Serial.print(msg); Serial.print("\n*** Request sent, receiving response..."); while (!!!client.available()) { delay(50); Serial.print("."); } Serial.println(); Serial.println("Got response"); while(client.available()){ Serial.write(client.read()); } Serial.println(); Serial.println("closing connection"); client.stop(); } void initWifi() { Serial.print("Connecting to: "); Serial.print(WiFi.SSID()); WiFi.mode(WIFI_STA); WiFi.begin(ssid, password); while (WiFi.status() != WL_CONNECTED) { delay(250); Serial.print("."); } Serial.println(""); Serial.print("WiFi connected, IP address: "); Serial.println(WiFi.localIP()); } |
You will also get the above code on our ESP32 IBM Watson IoT Example repository on GitHub as detect-smartwatch-on-dashboard-widget.ino.
As you can see, connection and disconnection are two separate functions doWiFiClientSecure() and doWiFiClientLost() :
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void doWiFiClientSecure() { WiFiClientSecure client; Serial.print("connect: "); Serial.println(urlHost); while ( ! client.connect(urlHost.c_str(), urlPort)) { Serial.print("."); } Serial.println("Connected"); String postData = String("{ \"d\": {\"Our device found!\": \"") + millis()/1000 + "\"} }"; String msg = "POST " + urlPath + " HTTP/1.1\r\n" "Host: " + urlHost + "\r\n" "" + authHeader + "" "Content-Type: application/json\r\n" "Content-Length: " + postData.length() + "\r\n" "\r\n" + postData; client.print(msg); Serial.print(msg); Serial.print("\n*** Request sent, receiving response..."); while (!!!client.available()) { delay(50); Serial.print("."); } Serial.println(); Serial.println("Got response"); while(client.available()){ Serial.write(client.read()); } Serial.println(); Serial.println("closing connection"); client.stop(); } void doWiFiClientLost() { WiFiClientSecure client; Serial.print("connect: "); Serial.println(urlHost); while ( ! client.connect(urlHost.c_str(), urlPort)) { Serial.print("."); } Serial.println("Connected"); String postData = String("{ \"d\": {\"Our device is away!\": \"") + millis()/1000 + "\"} }"; String msg = "POST " + urlPath + " HTTP/1.1\r\n" "Host: " + urlHost + "\r\n" "" + authHeader + "" "Content-Type: application/json\r\n" "Content-Length: " + postData.length() + "\r\n" "\r\n" + postData; client.print(msg); Serial.print(msg); Serial.print("\n*** Request sent, receiving response..."); while (!!!client.available()) { delay(50); Serial.print("."); } Serial.println(); Serial.println("Got response"); while(client.available()){ Serial.write(client.read()); } Serial.println(); Serial.println("closing connection"); client.stop(); } |
On IBM Watson IoT dashboard, create an “all device properties” card. There is nothing more to explain.
About Abhishek Ghosh
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