@al1fch Hi,
try the code below (install the latest ArduinoBLE library through Library Manager).
/* * GUI-O Basic BLE example for Arduino UNO R4 WiFi * * Uses the ArduinoBLE library and Nordic UART Service (NUS) UUIDs. * * Connect an LED (with a suitable series resistor) to PWM pin D9. * The onboard LED is not used because brightness control requires PWM. * * SPDX-License-Identifier: BSD-3-Clause */ #include <ArduinoBLE.h> namespace led { constexpr uint8_t PIN = 9; // UNO R4 WiFi PWM-capable pin } namespace uuid { constexpr char SERVICE[] = "6E400001-B5A3-F393-E0A9-E50E24DCCA9E"; constexpr char RX[] = "6E400002-B5A3-F393-E0A9-E50E24DCCA9E"; constexpr char TX[] = "6E400003-B5A3-F393-E0A9-E50E24DCCA9E"; } namespace ble { // A 20-byte payload works without depending on a larger negotiated MTU. constexpr size_t NOTIFY_CHUNK_SIZE = 20; constexpr int RX_BUFFER_SIZE = 512; } void parseGuioMsg(const String &msg); void sendMsg(const String &msg); BLEService nusService(uuid::SERVICE); // GUI-O writes commands to RX. BLECharacteristic rxCharacteristic( uuid::RX, BLEWrite | BLEWriteWithoutResponse, ble::RX_BUFFER_SIZE ); // UNO R4 sends GUI commands through TX notifications. BLECharacteristic txCharacteristic( uuid::TX, BLENotify, ble::NOTIFY_CHUNK_SIZE ); bool wasConnected = false; void setup() { Serial.begin(115200); pinMode(led::PIN, OUTPUT); analogWrite(led::PIN, 0); if (!BLE.begin()) { Serial.println("Failed to initialize BLE!"); while (true) { delay(1000); } } BLE.setLocalName("BasicBLE_NUS"); BLE.setDeviceName("BasicBLE_NUS"); BLE.setAdvertisedService(nusService); nusService.addCharacteristic(rxCharacteristic); nusService.addCharacteristic(txCharacteristic); BLE.addService(nusService); BLE.advertise(); Serial.println("BLE advertising started."); } void loop() { BLE.poll(); BLEDevice central = BLE.central(); const bool connected = central && central.connected(); if (connected && !wasConnected) { Serial.print("Connected to: "); Serial.println(central.address()); wasConnected = true; } if (!connected && wasConnected) { Serial.println("Disconnected!"); wasConnected = false; // Explicitly resume advertising for reliable reconnection. BLE.advertise(); } if (connected && rxCharacteristic.written()) { const int length = rxCharacteristic.valueLength(); if (length > 0) { String msg; msg.reserve(length); const uint8_t *value = rxCharacteristic.value(); for (int i = 0; i < length; ++i) { msg += static_cast<char>(value[i]); } parseGuioMsg(msg); } } } /***************************/ /* IMPLEMENT YOUR GUI HERE */ /***************************/ void sendMsg(const String &msg) { if (!wasConnected) { return; } const uint8_t *data = reinterpret_cast<const uint8_t *>(msg.c_str()); size_t remaining = msg.length(); while (remaining > 0) { const size_t chunkLength = remaining > ble::NOTIFY_CHUNK_SIZE ? ble::NOTIFY_CHUNK_SIZE : remaining; if (!txCharacteristic.writeValue(data, chunkLength)) { Serial.println("Failed to send BLE notification."); return; } data += chunkLength; remaining -= chunkLength; BLE.poll(); delay(10); } } void parseGuioMsg(const String &msg) { if (msg.startsWith("@init")) { Serial.println("GUI-O app is requesting INITIALIZATION!"); // Clear screen and set background. sendMsg("@cls\r\n"); sendMsg("@guis BGC:#FFFFFF\r\n"); delay(100); // Initialize simple example GUI. sendMsg("|LB UID:title X:50 Y:15 TXT:\"Simple light switch\" FFA:\"font8\" FSZ:3.5\r\n"); sendMsg("|LB UID:tap_me X:50 Y:70 TXT:\"TAP ME!\" FFA:\"font8\" FSZ:3 FFA:\"font5\"\r\n"); sendMsg("|CB UID:brightness X:50 Y:50 W:90 BTH:5 HAH:8 HAW:8 VIS:0 STA:135 ENA:45 FGC:#000000 SFGC:#FFFF00 BGC:#CBCBCB\r\n"); sendMsg("|IM UID:light_off X:50 Y:50 IP:\"https://i.imgur.com/3VbsS0Z.png\" VIS:1\r\n"); sendMsg("|IM UID:light_on X:50 Y:50 IP:\"https://i.imgur.com/gNdck9A.png\" VIS:0\r\n"); } else if (msg.startsWith("@light_off")) { Serial.println("GUI-O app is requesting LIGHT ON!"); sendMsg("@light_off VIS:0\r\n"); sendMsg("@light_on VIS:1\r\n"); sendMsg("@brightness VIS:1 VAL:100\r\n"); analogWrite(led::PIN, 255); } else if (msg.startsWith("@light_on")) { Serial.println("GUI-O app is requesting LIGHT OFF!"); sendMsg("@light_off VIS:1\r\n"); sendMsg("@light_on VIS:0\r\n"); sendMsg("@brightness VIS:0 VAL:0\r\n"); analogWrite(led::PIN, 0); } else if (msg.startsWith("@brightness")) { const int idx = msg.indexOf(' '); if (idx > 0) { const int val = msg.substring(idx + 1).toInt(); if (val >= 0 && val <= 100) { Serial.print("GUI-O app is requesting LIGHT BRIGHTNESS: "); Serial.println(val); const int pwmValue = map(val, 0, 100, 0, 255); analogWrite(led::PIN, pwmValue); } } } }I just used Chat to port the code from ESP32 on the GUI-O website. Should work...
Best regards,
Kl3m3n