LoRaProMini

LoRaProMini - A low power LoRaWAN Node

A LoRaWAN sensor node, based on ATmega328P MCU (Arduino Pro Mini) and RFM95W/SX1276 LoRa Transceiver.

The module can be used:

• Collect various climate values with environmental sensors. See Environmental (Weather/Clima) Sensor
• Tell if the letter carrier has put new letters in your mailbox. See Mailbox Monitor
• Notify if someone rang the doorbell
• Act a wirless button
• and many more...

Features

• Deep sleep MCU and sensors between data transmissions
• Two interrupt inputs could use to wake up the MCU and sensors from deep sleep
• Confirmend und unconfirmend data up messages
• Ultra low power consumption. Under 10μA with all features and sensors
• Power input 3.5-6V:
  • Battery (Li-Ion or Li-SOCl2 works fine)
  • Battery with solar charger
• Sensor support
  • Bosch BME280 (humidity, barometric pressure and ambient temperature)
  • Maxim DS18B20(+)/DS18S20(+)/DS1822 1-Wire temperature sensor

Warning

LoRaProMini does not take care of the compliance with the duty cycle limitation. Please select only transmission intervals that are within the legal limits (1%/0.1%). Please also note that the interrupt inputs may cause additional transmissions if this function is activated.

PCB Ordering

:point_up: I still have a few PCBs left. If you are interested please contact me. Contact details can be found here: https://github.com/foorschtbar or visit my Tindie store:

Example Applications

Environmental (Weather/Clima) Sensor

• Download Radiation Shield STL
• Buy Waterproof LED Solar Light

Mailbox Monitor

• Download Case STL
• Buy Normally Opened Reed Switches

More pics

The Things Stack configuration

• LoRaWAN version MAC V1.0.3

How to use

1. Manufacture the PCB. Here you find the Gerber files
2. Assemble the PCB. Here you find the Bill of Materials (BOM)
   • Attention: The current version (v3.1) of the PCB has no ISP header! A pre-burned Atmega328P must be installed. I got one from an Arduino Pro Mini Board (3.3V 8 Mhz), because a completely assembled Arduino is cheaper than a single chip
3. Flash config firmware (See How to flash)
4. Start voltage calibration from menu
5. Start configuration builder Configuration Builder
6. Measure the voltage with a multimeter
7. Insert multimeter voltage and the analog value in the Volts-per-bit (VPB) calculator to get VPB factor.
8. If u have a adjustable power supply, try different voltages to find best factor. Warning: The maximum voltage is 6 Volt
9. Fill out the other fields like activation methode, session keys and EUIs
10. Write configuration to EEPROM using configuration menu
11. Check written configuration via configuration menu
12. Flash debug or release firmware (See How to flash)
13. Finish

How to flash

avrdude-F -v -c arduino -p atmega328p -P <COM PORT> -b 57600 -D -U flash:w:<FIRMWARE FILE>:i

Example:

avrdude -F -v -c arduino -p atmega328p -P COM4 -b 57600 -D -U flash:w:firmware_1.0_config.hex:i

Firmware Changelog

Version 2.7

• Fixed a problem of resetting the interrupt trigger too early.

Version 2.6

• Second attempt to solve the unnecessary delay due to the duty cycle limitation. Overflow of timer0 freezes the MCU after around 20 transmissions.

Version 2.5

• Fixed problem with duty cycle limitation
• Fixed MCU deepsleep inaccuracy

Version 2.4

• An external interrupt during a transmission terminates the transmission and starts a new transmission.
• Enabled Link Check Mode

Version 2.3

• Fixed Typo

Version 2.2

• An additional send delay between 0 and 20s has been added to avoid overlaps between different nodes with exactly the same send interval
• Some flash memory optimizations

Version 2.1

• Improved (debug) logging to serial output
• BME sends -127°C (link DS18x) if no sensor was found

Version 2.0

• Added wake up trough interrupt pins
• Added option for disable interrupt pins
• Added option for confirmed uplink
• Changed LoRaWAN data up message
  • Added state of interrupt pins
  • Combined major and minor version byte into a single byte (4 bits for major and 4 bits for minor)

Version 1.1

• Only for testing CI Pipeline

Version 1.0

• Initial Version

PCB Changelog

Version 3.2

• Fixed C7 (Replaced 10uF with 100nF)

Version 3.1

• Added white field to specify the Node ID

Version 3.0

• Removed Arduino Pro Mini Dauther PCB
• Added ATMEGA328P direct to the PCB
• Added pins for unused GPIOs
• Added D2 and D3 with Pulldowns and connector as external interrupts (need FW v2.0 or higher)

Version 2.2

• Added RST pin to connector for programming

Version 2.1

• Added connector for programming

Version 2.0

• Smaller PCB
• Rounded Edges
• Fixed issue with DS18x onboard pin mapping

Version 1.0

• Initial PCB

TTS Payload Formatter (formerly TTN Payload Decoder)

function decodeUplink(input) {
  var bytes = input.bytes;

  var itrTrigger = (bytes[0] & 0x1) !== 0; // Message was triggered from interrupt (bit 0)
  var itr0 = (bytes[0] & 0x2) !== 0; // Interrupt 0 (bit 1)
  var itr1 = (bytes[0] & 0x4) !== 0; // Interrupt 1 (bit 2)
  var bat = (bytes[1] << 8) | bytes[2]; // Battery
  var fwversion = (bytes[3] >> 4) + "." + (bytes[3] & 0xf); // Firmware version
  var temp1 = (bytes[4] & 0x80 ? 0xffff << 16 : 0) | (bytes[4] << 8) | bytes[5]; // BME Temperature
  var humi1 = (bytes[6] << 8) | bytes[7]; // BME Humidity
  var press1 = (bytes[8] << 8) | bytes[9]; // BME Pressure
  var temp2 =
    (bytes[10] & 0x80 ? 0xffff << 16 : 0) | (bytes[10] << 8) | bytes[11]; // DS18x Temperature

  var mbStatus = "UNKNOWN";
  if (itr0) {
    mbStatus = "FULL";
  } else if (itr1) {
    mbStatus = "EMPTY";
  }

  return {
    data: {
      interrupts: {

ToDo

• Go to sleep immediately when voltage is too low
• Multi point calibration for battery voltage
• Set ADR (On/Off)
• Set SF (7-12)
• Allow change of NetID
• Add wake up trough interrupt pins
• Move Major- and Minorversion byte to single byte. 4 bits for major and 4 bits for minor.
• Add option for Confirmed Uplink to config
• Add CI/CD pipeline to build firmware
• Rewirte VBP calculator in Configuration Builder
• Move config to EEPROM
• Added special firmware to change configs
• Build HTML/JS Interface to build configs
• Add CRC32 check
• Test ABP
• Test OTAA
• Deploy config tool via GitHub Pages
• Fix problem when checksum in pastend config had zeros O.o
• Add random EUI generator button to config tool
• Parse config string to GUI fields