IoTProject

Project for the course Embedded Software for the Internet of Things @ UniTN fall 2021, made by me Eric.

It consists of connecting the MSP432P401R and the NodeMCU ESP8266 microcontrollers in order to send microphone data to a server and then visualizing the waveform on a iOS app.

If loud noises are detected by the microcontroller, a notification message is sent to the smartphone using a Telegram bot, since I do not have an Apple Developer Account subscription.

HW Requirements

For this project it is used:

• Texas Instrument MSP432P401R LaunchPad Development Kit
• Texas Instrument BoosterPack MK II
• NodeMCU Amica ESP8266
• A breadboard
• Some jumpers
• 2 USB cables

SW Requirements

• Code Composer Studio v10.4.0.00006
• NodeMCU PyFlasher
• Apache httpd v2.4.51
• Telegram Bot API key
• NodeJS (with express and node-telegram-bot-api modules installed)

Setting up

MPS432 Firmware

For this project, the NodeMCU needs to have flashed this firmware, download the one with this header:

• ESP8266 MQTT transparently transmits AT firmware (AT port is changed to UART0)

It is necessary in order to communicate with the NodeMCU ESP8266 with AT commands through UART. After downloading it, flash the NodeMCU ESP8266 with the firmware using the NodeMCU PyFlasher

You can test it using a serial console with baud rate of 115200 and both CR and LF (like the one in the Arduino IDE) and type AT, if the answer is OK that's all set!

Apache httpd

The purpose of utilizing a Apache httpd is to use it as a Proxy Server for decoupling the HTTPS requests from the NodeMCU that are too memory intensive for the latter. So, the NodeMCU will do normal HTTP requests that will be handled by the Proxy and redirected as HTTPS to the webisites. If you plan to run the server locally on your computer, skip this part.

Firstly, set up Apache httpd by modifying the httpd.conf file

brew install httpd
nano /usr/local/etc/httpd/httpd.conf

Uncomment these lines at the start of the file

LoadModule proxy_module modules/mod_proxy.so
LoadModule proxy_connect_module modules/mod_proxy_connect.so
LoadModule proxy_http_module modules/mod_proxy_http.so
LoadModule ssl_module modules/mod_ssl.so

Add this at the bottom of the file replacing SERVER_ADDRESS (e.g. https://yourserver.com/api) with the address of your server

<IfModule mod_proxy.c>

ProxyRequests Off

<Proxy *>
Order deny,allow
Allow from all
</Proxy>

SSLProxyEngine on
ProxyPass /api SERVER_ADDRESS
ProxyPassReverse /api SERVER_ADDRESS

</IfModule>

<Proxy *>

Then run the proxy server sudo brew services start httpd

The default port for httpd is 8080, and it's the one used in this project. Remember to have a static IP address on the PC running the Proxy (the one that I use will be 192.168.1.37)

Code Composer Studio

This project makes use of TI's DriverLib: download it and link the files required for interacting with the BoosterPack MK II sensors and establishing a connection with the ESP8266 through UART communication: go to the Project's properties, and:

• Under Arm Compiler/Include Options include the path to your DriverLib installation (/simplelink_msp432p4_sdk_3_40_01_02/source).
• Under Arm Linker/File Search Path include the DriverLib (/simplelink_msp432p4_sdk_3_40_01_02/source/ti/devices/msp432p4xx/driverlib/ccs/msp432p4xx_driverlib.lib).

This project contains some readapted libraries (to interface with the NodeMCU ESP8266 through UART) found here, they are inside the CCS project with these names:

• Devices
• Hardware

MSP432P401R and NodeMCU ESP8266 connections

Connect directly with some jumpers, or even with a breadboard, the two microcontrollers like so:

* GND = GND
* TX = P3.2
* RX = P3.3
* RST = P6.1 */

If the microcontroller reads weird data from the microphone, remove VCC and GND jumpers and use a USB cable to power the ESP8266 module

Secrets

You need to add a secrets.h file in your CCS Project folder containing your Wi-Fi SSID and password like so:

#ifndef SECRETS_H_
#define SECRETS_H_

#define SSID "YOUR_SSID"
#define PWD "YOUR_WIFI_PWD"


#endif /* SECRETS_H_ */


#### UART
 Inside the `main.c` file there is a configuration for UART communication which uses the NodeMCU ESP8266's default baud rate of 115200 and [CR][LF] (\r\n)
  ```eUSCI_UART_ConfigV1 UART2Config =
{
     EUSCI_A_UART_CLOCKSOURCE_SMCLK,
     13,
     0,
     37,
     EUSCI_A_UART_NO_PARITY,
     EUSCI_A_UART_LSB_FIRST,
     EUSCI_A_UART_ONE_STOP_BIT,
     EUSCI_A_UART_MODE,
     EUSCI_A_UART_OVERSAMPLING_BAUDRATE_GENERATION,
     EUSCI_A_UART_8_BIT_LEN
};

REST API and Telegram Bot Server

The server in this project is plug-and-play, you just need to set the port, in case you don't want to use the port 3000, and then add a secrets.js file containing your Telegram Bot token API and the chatID of your account like so:

const token = 'YOUR_TOKEN';
const myChatID = YOUR_CHATID;

module.exports = { token, myChatID }

iOS APP

Import the Xcode project and run it with your iPhone as target device

Usage

• Run the server
• Flash the MSP432 with the CCS program
• Open the app on your iPhone
• enjoy

You can find a video demo here

Credits

I made this project by myself, but thanks to UniTN and the prof. of the course Embedded Software for the Internet of Things for giving me this great opportunity.