ATtiny-LoRa-EnvSensor

I am currently developing a ATTiny1614 + RFM95W + BME280 environment sensor which will send data to The Things Network via an existing gateway. The new ATTiny boards support hardware SPI which is what I am using here to communicate between the uC and different modules.

Hardware Toolchain

The hardware I selected:

• Self-designed ATTinyX14 Development Board (Schematics to be added)
• RFM95W with antenna
• BME280 3.3v with SPI interface (6-pin board)

Tools I am using for development:

• Atmel Studio 7
• Atmel-ICE / MPLAB® PICkit 4
• Kingst Logic Analyzer

Modification

• For BME280 take out all the resistors on the surface to reduce power consumption by ~450uA. We are using SPI so no pull-up resistors are needed here.

The Things Network

• I haven't done anything on OTAA, and currently keys are hard-coded.
• Copy key.example.h file and name it key.h, then replace the values there.

Power consumption

I don't have a precise tool to measure low current, but based on my multimeter:

• Wake up time lasts for about 0.2s, not sure the total power consumption, but peak current is around 60mA.
• Sleep current is around 7uA.

Schematics