Week 14 Interface and Application Programming¶

Group assignment:: Compare as many tool options as possible.; Document your work on the group work page and reflect on your individual page what you learned.
Individual assignment: Write an application for the embedded board that you made. that interfaces a user with an input and/or output device(s)

Packages¶

We took a look at a number of tools to interface with our board over a variety of communication protocols. Since both of us are interested in communicating with our boards wirelessly, we especially focussed on those options.

BLE¶

MIT App Inventor¶

App Inventor is an open source app creation tool that works across platforms. It also has plugins to run BLE and there are YouTube tutorials like this one from the “Science Fun” channel that describe how to do it easily.

MIT App Inventor interface.

Pros:: Block coding so do not have to learn a bespoke language; Built in plug in for BLE; Free and open source; Sample code available
Cons:: Push notifications are not supported; Limited customization; Block coding interface may prove frustrating

Adafruit Bluefruit Connect¶

Bluefruit Connect is an app for Android and iOS that allows you to communicate with devices over BLE and UART.

Bluefruit app.

Pros:: Easy to use interface; Built in buttons and color picker; Sample code available; Jeremy tested it during his week 10 exploration and proved that it worked
Cons:: Not customizable; Jeremy has had issues with data transmission from the color picker

Java Script¶

JS is a popular coding language that is used to interface with websites. It can also be to control BLE devices localy through the web Bluetooth API. While researching this option we found some good tutorials about how to do this. In particular, the one from Confidence Okoghenun was quite useful where he creates a BLE heart monitor that pushes its data to a website via BLE.

Pros:: Sample code available; Allows a different method; Can use on smartphone via emulation on the Nordic nRF Connect App; Customizable
Cons:: Bigger lift than the other options for BLE; Emulation does not work on iOS

WiFi - Arduino¶

For WiFi enabled microcontroller boards using the Arduino IDE, foundational libraries can be used to connect to WiFi networks and communicate using common protocols. Early versions of the Arduino WiFi library relied on the (retired) Arduino WiFi Shield. More recent boards, particularly ESP32, employ a similar WiFi.h library specifically designed for the board (e.g., ESP32). For example:

The WiFi library can be used in conjunction web protocol libraries in order to run web servers and web services on the microcontroller board.

Web Server¶

A basic web server can be set up using the Arduino WiFi Network, WiFiServer and WiFiClient functionality. This allows client interaction with the microcontroller board using web protocols. For example:

Pros:: Direct web service connection to microcontroller board; Sample code available
Cons:: Limited onboard memory for web assets

Web Socket Server¶

Standard web communication involves a basic request / response model. In addition to the standard web server interaction, web socket protocols can be used for two-way web communication. For example:

Pros:: Direct web services connection to microcontroller board; Two-way communication with microcontroller as server; Sample code available
Cons:: Greater complexity for communication design; Limited onboard memory for web assets

WiFi - IoT Platforms¶

Adafruit IO¶

Adafruit IO is a web service platform built for IoT applications. It has data feeds that can be setup to injest and send data to WiFi or other connected devices. Feeds can send data via the API or MQTT and there is sample code to help set this up.

Sample dashboard done in Adafruit IO transmitting data from a Particle Argon WiFi device in Jeremy's Office

Pros:: Easy to use and setup; Jeremy has used a number of times in past projects; Web app works really well for a app-like experience
Cons:: Rate limited; Limited to 10 data streams in the free tier.

Blynk¶

Blynk is a low code IoT platform that allows users to build custom apps and communicate with connected devices easily. The Blynk interface can be accessed from a web browser or the app. Devices can be setup easily and dev boards like the XIAO can be setup to talk to the Blynk service via their Arduino IDE library.

Jeremy used this service in Week 4 to validate Wokwi simulation.

Pros:: Free tier for makers; Easy to connect devices; Proven to work with XIAO boards; Jeremy has used a number of times in past projects; Gives full app experience; Easy to modify the app without code
Cons:: No BLE support; Further customization requires subscription

Losant¶

Losant is an enterprise IoT platform. It is a fully functional backend and dashboard solution that can push and pull data from devices for monitoring, control, and automation. It can be used to control connected devices with simple Arduino code.

Jeremy uses Losant in concert with a Particle Boron Cellular device to monitor his greenhouse.

Losant dashboard that Jeremy built to monitor his greenhouse.

Pros:: Good amount of data allocation for prototype uses; Can injest data from Particle, MQTT, or webhook; Fully customizable dashboards that play well on mobile as webapp
Cons:: 10 device limit in free tier; Incredibly expensive to deploy broadly; Best suited for industrial IoT application for high margin monitoring work.