{"id":119,"date":"2021-12-03T14:29:43","date_gmt":"2021-12-03T14:29:43","guid":{"rendered":"https:\/\/www.bleuio.com\/blog\/?p=119"},"modified":"2022-07-01T10:37:11","modified_gmt":"2022-07-01T10:37:11","slug":"how-to-make-a-ble-enabled-smart-bulb-with-stm32-and-bleuio","status":"publish","type":"post","link":"https:\/\/www.bleuio.com\/blog\/how-to-make-a-ble-enabled-smart-bulb-with-stm32-and-bleuio\/","title":{"rendered":"How To Make a BLE enabled Smart Bulb with STM32"},"content":{"rendered":"\n

Home automation involves automating household environment equipment. To achieve that, we have created a smart bulb that is easy to install, and the attached equipment can be controlled over a web browser or smartphone app. The aim of this project is to control different home appliances using a web browser or smartphone.<\/p>\n\n\n\n

1. Introduction<\/h2>\n\n\n\n

The project is showcasing a simple way of using the the BleuIO Dongle to turn on and off a light bulb that is connected to the STM32 Nucleo-144 via a 5V Relay.<\/p>\n\n\n\n

You will need two dongles, one connected to the Nucleo board and one connected to a computer, running the web script.
When the BleuIO Dongle is connected to the Nucleo boards USB port the STM32 will recognize it and directly start advertising. This allows the other Dongle to connect to it.<\/p>\n\n\n\n

It will also accept 3 different inputs from the UART:<\/p>\n\n\n\n

input<\/th>result<\/th><\/tr><\/thead>
0<\/td>Send ATI (Request device information) command to BlueIO Dongle.<\/td><\/tr>
1<\/td>Manually turn the light bulb on<\/td><\/tr>
2<\/td>Manually turn the light bulb off<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

We have used a STM32 Nucleo-144 development board with STM32H743ZI MCU (STM32H743ZI micro mbed-Enabled Development Nucleo-144 series ARM\u00ae Cortex\u00ae-M7 MCU 32-Bit Embedded Evaluation Board) for this example.<\/p>\n\n\n\n

If you want to use another setup you will have to make sure it support USB Host and beware that the GPIO setup might be different and may need to be reconfigured in the .ioc file.<\/p>\n\n\n\n

WARNING \u2013 THIS PROJECT INVOLVES HIGH VOLTAGES THAT CAN CAUSE SERIOUS INJURY OR DEATH. PLEASE TAKE ALL NECESSARY PRECAUTIONS, AND TURN OFF ALL POWER TO A CIRCUIT BEFORE WORKING ON IT.<\/strong><\/p><\/blockquote>\n\n\n\n

2. Connecting the relay<\/h2>\n\n\n\n

Beware:<\/h3>\n\n\n\n

Always be very careful when experimenting with AC, electrical shock can result in serious injuries!<\/strong> NOTICE OF RISK; DISCLAIMER OF LIABILITY<\/p>\n\n\n\n

\"alt<\/figure>\n\n\n\n

Pinout and Connection to STM32<\/strong> For the DC part of the Relay circuit connect S (signal) to pin PE4 on the STM32 NUCLEO board, also connect the Power supply (+) and ground (-) to +5V and GND respectively.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n
\"alt<\/figure>\n\n\n\n

3. About the Code<\/h2>\n\n\n\n

You can get project HERE<\/a><\/strong>
https:\/\/github.com\/smart-sensor-devices-ab\/stm32_bleuio_lightbulb_example<\/a><\/p>\n\n\n\n

This project based on our previous STM32 project (https:\/\/github.com\/smart-sensor-devices-ab\/stm32_bleuio_example<\/a>) with these changes in the .ioc file:<\/p>\n\n\n\n

In the pinout view we set the GPIO PE4 to OUTPUT and labeled it to \u2018lightbulb\u2019.\"alt<\/p>\n\n\n\n

\n\n\n\n

In the USBH_CDC_ReceiveCallback function in USB_HOST\\usb_host.c we copy the CDC_RX_Buffer into a external variable called dongle_response that is accessable from the main.c file.<\/p>\n\n\n\n

void USBH_CDC_ReceiveCallback(USBH_HandleTypeDef *phost)\n{\n    if(phost == &hUsbHostFS)\n    {\n        \/\/ Handles the data recived from the USB CDC host, here just printing it out to UART\n        rx_size = USBH_CDC_GetLastReceivedDataSize(phost);\n        HAL_UART_Transmit(&huart3, CDC_RX_Buffer, rx_size, HAL_MAX_DELAY);\n\n        \/\/ Copy buffer to external dongle_response buffer\n        strcpy((char *)dongle_response, (char *)CDC_RX_Buffer);\n\n        memset(CDC_RX_Buffer,0,RX_BUFF_SIZE);\n        USBH_CDC_Receive(phost, CDC_RX_Buffer, RX_BUFF_SIZE);\n    }\n\n    return;\n}<\/code><\/pre>\n\n\n\n

In main.c we create a simple intepreter so we can react to the data we are recieving from the dongle.<\/p>\n\n\n\n
\/**\n  * @brief Simple dongle interpreter\n  * @retval None\n  *\/\nvoid dongle_interpreter(uint8_t * input)\n{\n\n    if(strlen((char *)input) != 0)\n    {\n        if(strstr((char *)input, \"\\r\\nADVERTISING...\") != NULL)\n        {\n            isAdvertising = true;\n        }\n        if(strstr((char *)input, \"\\r\\nADVERTISING STOPPED.\") != NULL)\n        {\n            isAdvertising = false;\n        }\n        if(strstr((char *)input, \"\\r\\nCONNECTED\") != NULL)\n        {\n            isConnected = true;\n            HAL_GPIO_WritePin(GPIOE, GPIO_PIN_1, GPIO_PIN_SET);\n        }\n        if(strstr((char *)input, \"\\r\\nDISCONNECTED\") != NULL)\n        {\n            isConnected = false;\n            HAL_GPIO_WritePin(GPIOE, GPIO_PIN_1, GPIO_PIN_RESET);\n        }\n        if(strstr((char *)input, \"L=0\") != NULL)\n        {\n            isLightBulbOn = false;\n            HAL_GPIO_WritePin(Lightbulb_GPIO_Port, Lightbulb_Pin, GPIO_PIN_RESET);\n\n            writeToDongle((uint8_t*)DONGLE_SEND_LIGHT_OFF);\n\n            uart_buf_len = sprintf(uart_tx_buf, \"\\r\\nLight bulb is %s\\r\\n\", isLightBulbOn ? \"on\":\"off\");\n            HAL_UART_Transmit(&huart3, (uint8_t *)uart_tx_buf, uart_buf_len, HAL_MAX_DELAY);\n        }\n        if(strstr((char *)input, \"L=1\") != NULL)\n        {\n            isLightBulbOn = true;\n            HAL_GPIO_WritePin(Lightbulb_GPIO_Port, Lightbulb_Pin, GPIO_PIN_SET);\n\n            writeToDongle((uint8_t*)DONGLE_SEND_LIGHT_ON);\n\n            uart_buf_len = sprintf(uart_tx_buf, \"\\r\\nLight bulb is %s\\r\\n\", isLightBulbOn ? \"on\":\"off\");\n            HAL_UART_Transmit(&huart3, (uint8_t *)uart_tx_buf, uart_buf_len, HAL_MAX_DELAY);\n        }\n    }\n    memset(&dongle_response, 0, RSP_SIZE);\n}<\/code><\/pre>\n\n\n\n

We also update the handleUartInput function so we can have manual control over the light bulb via the UART.<\/p>\n\n\n\n
\/**\n  * @brief Simple uart input handler\n  * @retval None\n  *\/\nvoid handleUartInput(UARTCommandTypeDef cmd)\n{\n    switch(cmd)\n    {\n        case UART_RX_0:\n        {\n            \/\/ 0\n            uart_buf_len = sprintf(uart_tx_buf, \"\\r\\n(0 pressed)\\r\\n\");\n            HAL_UART_Transmit(&huart3, (uint8_t *)uart_tx_buf, uart_buf_len, HAL_MAX_DELAY);\n            if(isBleuIOReady)\n            {\n                writeToDongle((uint8_t*)DONGLE_CMD_ATI);\n            } else\n            {\n                uart_buf_len = sprintf(uart_tx_buf, BLEUIO_NOT_READY_MSG);\n                HAL_UART_Transmit(&huart3, (uint8_t *)uart_tx_buf, uart_buf_len, HAL_MAX_DELAY);\n            }\n            uartStatus = UART_RX_NONE;\n            break;\n        }\n        case UART_RX_1:\n        {\n            \/\/ 1\n            uart_buf_len = sprintf(uart_tx_buf, \"\\r\\n(1 pressed light bulb on!)\\r\\n\");\n            HAL_UART_Transmit(&huart3, (uint8_t *)uart_tx_buf, uart_buf_len, HAL_MAX_DELAY);\n            HAL_GPIO_WritePin(Lightbulb_GPIO_Port, Lightbulb_Pin, GPIO_PIN_SET);\n            uartStatus = UART_RX_NONE;\n            break;\n        }\n        case UART_RX_2:\n        {\n            \/\/ 2\n            uart_buf_len = sprintf(uart_tx_buf, \"\\r\\n(2 pressed light bulb off!)\\r\\n\");\n            HAL_UART_Transmit(&huart3, (uint8_t *)uart_tx_buf, uart_buf_len, HAL_MAX_DELAY);\n            HAL_GPIO_WritePin(Lightbulb_GPIO_Port, Lightbulb_Pin, GPIO_PIN_RESET);\n\n            uartStatus = UART_RX_NONE;\n            break;\n        }\n        case UART_RX_NONE:\n        {\n            break;\n        }\n        default:\n        {\n            uartStatus = UART_RX_NONE;\n            break;\n        }\n    }\n}<\/code><\/pre>\n\n\n\n
We put the intepreter function inside the main loop.<\/p>\n\n\n\n
\/* Infinite loop *\/\n  \/* USER CODE BEGIN WHILE *\/\n  while (1)\n  {\n    \/* USER CODE END WHILE *\/\n    MX_USB_HOST_Process();\n\n    \/* USER CODE BEGIN 3 *\/\n    \/\/ Simple handler for uart input\n    handleUartInput(uartStatus);\n    \/\/ Inteprets the dongle data\n    dongle_interpreter(dongle_response);\n\n    \/\/ Starts advertising as soon as the Dongle is ready.\n    if(!isAdvertising && !isConnected && isBleuIOReady)\n    {\n        HAL_Delay(200);\n        writeToDongle((uint8_t*)DONGLE_CMD_AT_ADVSTART);\n        isAdvertising = true;\n    }\n  }\n  \/* USER CODE END 3 *\/<\/code><\/pre>\n\n\n\n
4. Using the example project<\/h2>\n\n\n\n
4.1 What you will need<\/h3>\n\n\n\n