A solar powered LoRa radio transmitting barometric pressure and altitude #LoRa #solar #tutorial @voltaicsystems

Lizabeth Arum at Voltaic shows how to create a LoRa wireless networked device with an Adafruit Feather M0 RFM95 LoRa Radio 900MHz connected to a sensor and powered by a e-Peas energy harvester and a Lithium Ion Capacitor (LIC). An MPL3115A2 – I2C Barometric Pressure / Altitude / Temperature Sensor measures barometric pressure and altitude.

The Adafruit Feather M0 with an RFM9x LoRa 868/915 MHz radio module that transmits and receives small packets of data is designed to make flexible wireless networks without the high power requirements of WiFi.

Each Adafruit LoRa device comes with a small label that contains a MAC address in the form 98:76:B6:xx:yy:zz. This might be a sticker attached to the device itself or included separately. The MAC address is needed when connecting the Feather to LoRaWAN. Speaking from experience, I suggest taking a photo of this sticker as a backup plan for when the sticker goes missing.

To make it easy to use the Feather for portable projects, Adafruit added a connector for a  3.7V Lithium polymer battery. The Feather can run off a battery or a micro USB, and you can use the USB input to recharge the battery. The Feather will automatically switch from the battery to USB power when available. The battery is also tied through a divider to an analog pin, so you can measure and monitor the battery voltage to detect when you need a recharge.

The module can be programmed in the Arduino IDE. To get the battery’s voltage, connect the battery to D9 (A7), read the pin voltage, and then double it to get the battery voltage.

The tutorial is an entry point into the world of solar-powered IoT. Programming and sizing a system are some of the practical aspects of designing energy-efficient remote data monitoring devices. Introducing the LIC demonstrates that a capacitor can provide a viable alternative to a battery for truly low-power devices. Using The Things Network and Qubitro dashboard brings an added dimension of network connectivity and data visualization to the project, making it a perfect blend of the practical IoT challenges you will face when designing your applications.

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