In this tutorial, the ATtiny85 is reintroduced, this time as a Bluetooth-enabled device. First, some of the basics of burning the bootloader to the ATtiny85 and using the Arduino board as an in-system programmer (ISP) are explored. Then, a CC2541 Bluetooth Low Energy (BLE) module is used to communicate with an iOS device using the BLExAR app. Lastly, temperature and humidity data is read by the ATtiny85 and transmitted via Bluetooth to the smartphone.

LoRa modules, such as the SX1276 used in this tutorial, are widely available and relatively inexpensive, all while being fully compatible with Arduino. LoRa modules are also modular in software and hardware: transmission power is configurable, the modules can be outfitted with antennae, and transmission speed and packet information size are both modifiable. In this tutorial, an Arduino board and SX1276 modules will be used to create a network of long range (LoRa) nodes designed to communicate and transport information. The use of antennae will also help broaden the range of the nodes, and tests in New York City will help quantify the efficiency and cone of functionality for such a node in a complex environment.

The NEO-6 is a miniature GPS module designed by u-blox to receive updates from up to 22 satellite on 50 different channels that use trilateration to approximate fixed position of a receiver device every second (or less, for some modules). The particular module used in this tutorial, the NEO-6M, is capable of updating its position every second and communicates with an Arduino board using UART serial communication. The NEO-6M uses the National Marine Electronics Association (NMEA) protocol which provides temporal and geolocation information such as Greenwich Mean Time (GMT), latitude, longitude, altitude, and approximate course speed. The NEO-6M and Arduino board will also be paired with an SD module to create a portable logger that acts as a retrievable GPS tracker.

In the tutorial, the simplest integrated IoT mesh network is explored, where Argon (WiFi + BLE) and Xenon (BLE) Particle boards are used to create an ultrasonic range detector (HC-SR04) that notifies an LED whether a threshold value has been crossed in front of the sensor. When the threshold is reached, a ‘trip’ is communicated to the mesh network and notifies the system via Bluetooth and WiFi.