A Minimalistic LoRaWAN Sensor Node

The ATTNode (short for ATTiny Node) is a minimalistic node for the LoraWAN Network. It is based on the widely available ATTiny MCU from Atmel/Microchip and the HopeRF RFM95W LoRa Wireless Module. It can be used with a variety of sensors, the provided firmware does support the I²C-sensors SHT21 and BME280 for measuring climate data (Temperature/Humidity/Atmospheric Pressure) and is meant to be used with The Things Network as backend. The node can last for several months using only a CR2032 button cell sending values from the above mentioned sensors every 10 minutes.

ATTNode v1 and v2
ATTNode v2 with BME280
ATTNode v2 Case
ATTNode v3 Prototype


  • Small Size, only 47x36mm (v1) / 34x26mm (v2) / 37.5x30.5 (v3)
  • Based on widely available Atmel ATTiny84(v1,v2) / ATTiny3216(v3) MCU and RFM95W LoRa-module
  • Free GPIO-Pins from the ATTiny + Power to connect sensors on a 2.54mm pitch header
  • Firmware support for SHT21/BME280 Climate Sensors, Brightness Measurement, Alarm Trigger and Beacon Mode
  • Optional on-board LED for status signaling
  • Powered by a single CR2032 lithium battery
  • Long battery runtime using the ATTinys deep sleep mode
  • Integrated 6-Pin programming header
  • Small component count
  • Possibility for edge-mount SMA connector or u.fl SMD connector (v2/v3)
  • Open Hardware and Software, KiCad Project for the PCB, Firmware and Case Designs can be found in the git repository

Downloads for Gerber- and STL-files as well as the BoM and assembly hints can be found at the subsites for the corresponding ATTNode Version.

The current versions are ATTNode v2.0 and ATTNode v3.0

Recent Posts

TinyLoRa is now ATTNode

Today I announce the renaming of the TinyLoRa project to ATTNode which is short for ATTiny Node. Reason for this is, that “LoRa” is a regsitered trademark of Semtech, which means that I could get into legal trouble using it for my “product”. Since I don’t have the time or money for a legal battle with a big corporation, I have decided to preemptively rename the project. The website will be located at www.

Measuring Brightness with a LED

twentysixer has developed a simple but effective way to detect brightness with the TinyLoRa. All that is needed is a simple LED: With the TinyLoRa and a simple led you can detect brightness and darkness. The LED is connected to 2 GPIOs in the reverse direction. The LED is charged and measured until it is discharged again. The darker it is, the longer it will take to discharge it. Clear LEDs with a low forward voltage are best suited, e.

Deep Sleep Current and Optimizing the BME280

Since the TinyLoRa Node does seem to get some interest in the last days the question of power consumption and deep sleep currents came up a few times. So here are some measurements I took as well as a way to potentially more than halve the deep sleep current when using one of the usual BME280 sensor modules. Deep Sleep Current Measurements I use the ATTiny84s deep sleep / powerdown feature and the internal watchdog to keep the power consumption low and get a useful battery life with a CR2032.

LoRa FrameCounter now Saved Across Reset/Power Loss

Up until now the Lora Frame Counter, which is a security feature to prevent replay attacks, was reset every time the ATTiny rebooted (e.g. because of reset or power loss). Because of this the Frame Counter Check in the settings of the Lora devices had to be disabled, or messages after a reset wouldn’t be processed by the TTN Backend. I have now implemented a way to save the Frame Counter in the ATTinys integrated EEPROM, so it will survive resets and power loss.

TinyLoRa v2 Case Available

3D-Printable Case for TinyLora v2 Available As promised I have now also designed a 3D-Printable case for the TinyLoRa v2 Boards. The Board is meant to be used with a small coil antenna directly mounted to the PCB. Here are some pictures: The STL and OpenSCAD files are available from the ATTNode v2 main page