ESP32_RELAY_X1 over BLE

esp32_x1_relay.hpp

/* -*- mode: c++ -*-
 *
 *  Copyright 2024 iomonad <iomonad@riseup.net>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the “Software”), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

#pragma once

#define SERVICE_UUID                "c0ffeeee-1337-1337-1337-c5c9c331914b"
#define CHARACTERISTIC_UUID         "beb5483e-36e1-4688-b7f5-ea07361b26a8"

// See: https://www.bluetooth.com/wp-content/uploads/Files/Specification/HTML/Assigned_Numbers/out/en/Assigned_Numbers.pdf?v=1716982826526
// Stealth car shit
#define RELAY_CHARACTERISTIC_UUID 0x0A88
#define RELAY_GPIO_PORT           0x10

#define BLE_MAGIC_SWITCH_ON   "K7v3JnhfL5Ar9n6"
#define BLE_MAGIC_SWITCH_OFF  "QNrGcirdP374uY5"

esp32_x1_relay.ino

/* -*- mode: c++ -*-
 *
 *  Copyright 2024 iomonad <iomonad@riseup.net>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the “Software”), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

#include "esp_err.h"
#include "esp_check.h"

#include <stdio.h>
#include <stdlib.h>
#include <memory>

#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/queue.h"
#include "freertos/semphr.h"

#include <BLEDevice.h>
#include <BLEServer.h>
#include <BLEUtils.h>
#include <BLE2902.h>
#include <BLEScan.h>
#include <BLEAdvertisedDevice.h>
#include <BLERemoteCharacteristic.h>

#include <EEPROM.h>

#include "esp32_x1_relay.hpp"

#if !defined(CONFIG_BT_SPP_ENABLED)
#error Serial Bluetooth not available or not enabled on the ESP32
#endif

static BLEServer *ble_server = NULL;
static BLECharacteristic* pCharacteristic = NULL;
static BLECharacteristic* relayCharacteristic = NULL;
static bool relay_enabled = false;
static bool isConnected = false;

static SemaphoreHandle_t ble_relay_sem;

/*    _____          __  .__      .__  __           */
/*   /  _  \   _____/  |_|__|__  _|__|/  |_ ___.__. */
/*  /  /_\  \_/ ___\   __\  \  \/ /  \   __<   |  | */
/* /    |    \  \___|  | |  |\   /|  ||  |  \___  | */
/* \____|__  /\___  >__| |__| \_/ |__||__|  / ____| */
/*         \/     \/                        \/      */

class BLECallbacks : public BLEServerCallbacks {
     void onConnect(BLEServer *pServer) {
	  printf("ble: new connection open\n");
	  isConnected = true;
     };

     void onDisconnect(BLEServer *pServer) {
	  printf("ble: device disconnected\n");
	  isConnected = false;
     }
};


class RelayCallback : public BLECharacteristicCallbacks {
     void onWrite(BLECharacteristic* ledCharacteristic) {
	  const std::string rxValue = ledCharacteristic->getValue();

	  if (xSemaphoreTake(ble_relay_sem, portMAX_DELAY) && isConnected) {
	       if (rxValue == BLE_MAGIC_SWITCH_ON) {
		    EEPROM.write(0x00, 0xFF);
		    digitalWrite(RELAY_GPIO_PORT, HIGH);
	       }
	       if (rxValue == BLE_MAGIC_SWITCH_OFF) {
		    EEPROM.write(0x00, 0x00);
		    digitalWrite(RELAY_GPIO_PORT, LOW);
	       }
	  } else {
	       printf("err: write on disconnect or semaphore timeout\n");
	  }
	  /* Release sem  */
	  xSemaphoreGive(ble_relay_sem);
     }
};

static void ble_server_lifecycle(void *_params) {
     for (;;) {
	  if (!isConnected) {
	       vTaskDelay(pdMS_TO_TICKS(500));
	       ble_server->startAdvertising();

	       printf("ble: advertising\n");
	  }
	  vTaskDelay(pdMS_TO_TICKS(10000));
     }
};

/* ___________       __                               .__        __    */
/* \_   _____/ _____/  |________ ___.__.______   ____ |__| _____/  |_  */
/*  |    __)_ /    \   __\_  __ <   |  |\____ \ /  _ \|  |/    \   __\ */
/*  |        \   |  \  |  |  | \/\___  ||  |_> >  <_> )  |   |  \  |   */
/* /_______  /___|  /__|  |__|   / ____||   __/ \____/|__|___|  /__|   */
/*         \/     \/             \/     |__|                  \/       */

void setup () {
     Serial.begin(115200);

     int relay_status = EEPROM.read(0x00);

     pinMode(RELAY_GPIO_PORT, OUTPUT);
     digitalWrite(RELAY_GPIO_PORT, (relay_status == 0x00) ? LOW : HIGH);

     BLEDevice::init("st_pierre");
     ble_server = BLEDevice::createServer();
     ble_server->setCallbacks(new BLECallbacks());

     ble_relay_sem = xSemaphoreCreateBinary();
     xSemaphoreGive(ble_relay_sem);

     BLEService *ble_svc = ble_server->createService(SERVICE_UUID);

     pCharacteristic = ble_svc->createCharacteristic(
	  CHARACTERISTIC_UUID,
	  BLECharacteristic::PROPERTY_READ   |
	  BLECharacteristic::PROPERTY_WRITE  |
	  BLECharacteristic::PROPERTY_NOTIFY |
	  BLECharacteristic::PROPERTY_INDICATE);

     relayCharacteristic = ble_svc->createCharacteristic(
	  (uint16_t) RELAY_CHARACTERISTIC_UUID,
	  BLECharacteristic::PROPERTY_READ   |
	  BLECharacteristic::PROPERTY_WRITE  |
	  BLECharacteristic::PROPERTY_INDICATE);

     relayCharacteristic->setCallbacks(new RelayCallback());

     /* Start SVC server */
     ble_svc->start();

     BLEAdvertising *pAdvertising = BLEDevice::getAdvertising();
     pAdvertising->addServiceUUID(SERVICE_UUID);
     pAdvertising->setScanResponse(false);
     pAdvertising->setMinPreferred(0x0);
     BLEDevice::startAdvertising();

     xTaskCreate(ble_server_lifecycle, "ble_mgmt_task", 10000, NULL, 1, NULL);
}

void loop () {}

Makefile

build:
	arduino-cli compile -v -p /dev/ttyUSB0 --fqbn esp32:esp32:esp32
flash:
	arduino-cli compile -v -p /dev/ttyUSB0 --fqbn esp32:esp32:esp32 -u

setup:
	arduino-cli core install esp32:esp32