How To Make a BLE enabled Smart Bulb with STM32 and BleuIO

1. Introduction

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.

2. Connecting the relay

Beware:

Always be very careful when experimenting with AC, electrical shock can result in serious injuries! NOTICE OF RISK; DISCLAIMER OF LIABILITY

3. About the Code

You can get project HERE
https://github.com/smart-sensor-devices-ab/stm32_bleuio_lightbulb_example

void USBH_CDC_ReceiveCallback(USBH_HandleTypeDef *phost)
{
if(phost == &hUsbHostFS)
{
// Handles the data recived from the USB CDC host, here just printing it out to UART
rx_size = USBH_CDC_GetLastReceivedDataSize(phost);
HAL_UART_Transmit(&huart3, CDC_RX_Buffer, rx_size, HAL_MAX_DELAY);
// Copy buffer to external dongle_response buffer
strcpy((char *)dongle_response, (char *)CDC_RX_Buffer);
memset(CDC_RX_Buffer,0,RX_BUFF_SIZE);
USBH_CDC_Receive(phost, CDC_RX_Buffer, RX_BUFF_SIZE);
}
return;
}
/**
* @brief Simple dongle interpreter
* @retval None
*/
void dongle_interpreter(uint8_t * input)
{
if(strlen((char *)input) != 0)
{
if(strstr((char *)input, "\r\nADVERTISING...") != NULL)
{
isAdvertising = true;
}
if(strstr((char *)input, "\r\nADVERTISING STOPPED.") != NULL)
{
isAdvertising = false;
}
if(strstr((char *)input, "\r\nCONNECTED") != NULL)
{
isConnected = true;
HAL_GPIO_WritePin(GPIOE, GPIO_PIN_1, GPIO_PIN_SET);
}
if(strstr((char *)input, "\r\nDISCONNECTED") != NULL)
{
isConnected = false;
HAL_GPIO_WritePin(GPIOE, GPIO_PIN_1, GPIO_PIN_RESET);
}
if(strstr((char *)input, "L=0") != NULL)
{
isLightBulbOn = false;
HAL_GPIO_WritePin(Lightbulb_GPIO_Port, Lightbulb_Pin, GPIO_PIN_RESET);
writeToDongle((uint8_t*)DONGLE_SEND_LIGHT_OFF); uart_buf_len = sprintf(uart_tx_buf, "\r\nLight bulb is %s\r\n", isLightBulbOn ? "on":"off");
HAL_UART_Transmit(&huart3, (uint8_t *)uart_tx_buf, uart_buf_len, HAL_MAX_DELAY);
}
if(strstr((char *)input, "L=1") != NULL)
{
isLightBulbOn = true;
HAL_GPIO_WritePin(Lightbulb_GPIO_Port, Lightbulb_Pin, GPIO_PIN_SET);
writeToDongle((uint8_t*)DONGLE_SEND_LIGHT_ON); uart_buf_len = sprintf(uart_tx_buf, "\r\nLight bulb is %s\r\n", isLightBulbOn ? "on":"off");
HAL_UART_Transmit(&huart3, (uint8_t *)uart_tx_buf, uart_buf_len, HAL_MAX_DELAY);
}
}
memset(&dongle_response, 0, RSP_SIZE);
}
/**
* @brief Simple uart input handler
* @retval None
*/
void handleUartInput(UARTCommandTypeDef cmd)
{
switch(cmd)
{
case UART_RX_0:
{
// 0
uart_buf_len = sprintf(uart_tx_buf, "\r\n(0 pressed)\r\n");
HAL_UART_Transmit(&huart3, (uint8_t *)uart_tx_buf, uart_buf_len, HAL_MAX_DELAY);
if(isBleuIOReady)
{
writeToDongle((uint8_t*)DONGLE_CMD_ATI);
} else
{
uart_buf_len = sprintf(uart_tx_buf, BLEUIO_NOT_READY_MSG);
HAL_UART_Transmit(&huart3, (uint8_t *)uart_tx_buf, uart_buf_len, HAL_MAX_DELAY);
}
uartStatus = UART_RX_NONE;
break;
}
case UART_RX_1:
{
// 1
uart_buf_len = sprintf(uart_tx_buf, "\r\n(1 pressed light bulb on!)\r\n");
HAL_UART_Transmit(&huart3, (uint8_t *)uart_tx_buf, uart_buf_len, HAL_MAX_DELAY);
HAL_GPIO_WritePin(Lightbulb_GPIO_Port, Lightbulb_Pin, GPIO_PIN_SET);
uartStatus = UART_RX_NONE;
break;
}
case UART_RX_2:
{
// 2
uart_buf_len = sprintf(uart_tx_buf, "\r\n(2 pressed light bulb off!)\r\n");
HAL_UART_Transmit(&huart3, (uint8_t *)uart_tx_buf, uart_buf_len, HAL_MAX_DELAY);
HAL_GPIO_WritePin(Lightbulb_GPIO_Port, Lightbulb_Pin, GPIO_PIN_RESET);
uartStatus = UART_RX_NONE;
break;
}
case UART_RX_NONE:
{
break;
}
default:
{
uartStatus = UART_RX_NONE;
break;
}
}
}
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */
MX_USB_HOST_Process();
/* USER CODE BEGIN 3 */
// Simple handler for uart input
handleUartInput(uartStatus);
// Inteprets the dongle data
dongle_interpreter(dongle_response);
// Starts advertising as soon as the Dongle is ready.
if(!isAdvertising && !isConnected && isBleuIOReady)
{
HAL_Delay(200);
writeToDongle((uint8_t*)DONGLE_CMD_AT_ADVSTART);
isAdvertising = true;
}
}
/* USER CODE END 3 */

4. Using the example project

4.1 What you will need

  • Two BleuIO dongles (https://www.bleuio.com/)
  • The script for the dongle (available on the source code inside web script folder)
  • A board with a STM32 Microcontroller with a USB port. (A Nucleo-144 development board: NUCLEO-H743ZI2, was used developing this example. (https://www.st.com/en/evaluation-tools/nucleo-h743zi.html)
    To connect the dongle to the Nucleo board a “USB A to Micro USB B”-cable with a USB A female-to-female adapter can be used.)

5. How to setup project

5.1 Downloading the project from GitHub

Get project HERE
https://github.com/smart-sensor-devices-ab/stm32_bleuio_lightbulb_example

5.2 Importing as an Existing Project

  • From STM32CubeIDE choose File>Import…
  • You should see the project “stm32_bleuio_example”, check it and click ‘Finish’.

6. Running the example

  • In STMCubeIDE click the hammer icon to build the project.
  • Open up the ‘STMicroelectronics STLink Viritual COM Port’ with a serial terminal emulation program like TeraTerm, Putty or CoolTerm.Serial port Setup:
    Baudrate: 115200
    Data Bits: 8
    Parity: None
    Stop Bits: 1
    Flow Control: None
  • Connect the BleuIO Dongle before running the example .
  • In STMCubeIDE click the green play button to flash and run it on your board. The first time you click it the ‘Run Configuration’ window will appear. You can just leave it as is and click run.
  • You should be greeted by this welcome message:
  • 1 to turn on lightbulb.
  • 2 to turn off lightbulb.

7. Controlling the light from a web browser

We wrote a simple script that connects to the dongle and sends signals to toggle the light from the web browser.

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<link
href="https://cdn.jsdelivr.net/npm/bootstrap@5.1.3/dist/css/bootstrap.min.css"
rel="stylesheet"
integrity="sha384-1BmE4kWBq78iYhFldvKuhfTAU6auU8tT94WrHftjDbrCEXSU1oBoqyl2QvZ6jIW3"
crossorigin="anonymous"
/>
<title>Control Light using Bleutooth Low Energy</title>
</head>
<body class="mt-5">
<div class="container mt-5">
<h1 class="mb-5">Control Light using Bleutooth Low Energy</h1>
<button class="btn btn-success" id="connect">Connect</button>
<button class="btn btn-warning" id="lightOn" disabled>Turn On</button>
<button class="btn btn-danger" id="lightOf" disabled>Turn Off</button>
</div>
<div class="container mt-5">
<img id="light" src="light_off.png" alt="" />
</div>
<script src="script.js"></script>
</body>
</html>
import * as my_dongle from "bleuio";
const dongleToConnect = "[0]40:48:FD:E5:35:A5";
import lightOnImg from "./light_on.png";
import lightOfImg from "./light_off.png";
document.getElementById("connect").addEventListener("click", function () {
my_dongle.at_connect();
document.getElementById("lightOn").disabled = false;
document.getElementById("lightOf").disabled = false;
document.getElementById("connect").disabled = true;
});
document.getElementById("lightOn").addEventListener("click", function () {
my_dongle
.ati()
.then((data) => {
//make central if not
if (JSON.stringify(data).includes("Peripheral")) {
console.log("peripheral");
my_dongle.at_central().then((x) => {
console.log("central now");
});
}
})
.then(() => {
// connect to dongle
my_dongle
.at_getconn()
.then((y) => {
if (JSON.stringify(y).includes(dongleToConnect)) {
console.log("already connected");
} else {
my_dongle.at_gapconnect(dongleToConnect).then(() => {
console.log("connected successfully");
});
}
})
.then(() => {
// send command to control light
my_dongle.at_spssend("L=1").then(() => {
console.log("Turned on");
document.getElementById("light").src = lightOnImg;
});
});
});
});
document.getElementById("lightOf").addEventListener("click", function () {
my_dongle
.ati()
.then((data) => {
//make central if not
if (JSON.stringify(data).includes("Peripheral")) {
console.log("peripheral");
my_dongle.at_central().then((x) => {
console.log("central now");
});
}
})
.then(() => {
// connect to dongle
my_dongle
.at_getconn()
.then((y) => {
if (JSON.stringify(y).includes(dongleToConnect)) {
console.log("already connected");
} else {
my_dongle.at_gapconnect(dongleToConnect).then(() => {
console.log("connected successfully");
});
}
})
.then(() => {
// send command to control light
my_dongle.at_spssend("L=0").then(() => {
console.log("Turned off");
document.getElementById("light").src = lightOfImg;
});
});
});
});
- Open this site https://bleuio.com/web_terminal.html and click connect to dongle.
- Select the appropriate port to connect.
- Once it says connected, type **"ATI"**. This will show dongle information and current status.
- If the dongle is on peripheral role, set it to central by typing **"AT+CENTRAL"**
- Now do a gap scan by typing **"AT+GAPSCAN"**
- Once you see your dongle on the list ,stop the scan by pressing control+c
- Copy the ID and paste it into the script (script.js) line #2

--

--

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store