The “BeeMonitor” project

Beekeeping is a time consuming hobby, it’s not so easy as it sounds. Making sure the bees are healthy takes a lot of knowledge and experience.

Adding sensors to a beehive helps the beekeeper to monitor the hive and take action when things are not as expected.

Therefor I decided to make my own “BeeMonitor”. Starting with the electronics, connecting our hives to the internet!

The BeeMonitor with sensors

The technical side:

The BeeMonitor is a “battery powered wireless datalogger”. It’s a compact controller with user-changeable dipswitches, RGB led, buzzer, “plug & play” RJ12 connectors designed for different sensors combinations and is capable to carry 2 different wireless modules, a RFM69W for use in a private network or the RFM95W to connect to an LPWAN IoT network (LoRaWAN) on sub-gigahertz radio bands. Powered by 2 AAA battery’s, operating on 3V the”BeeMonitor” only consumes 35nA in sleep the making the battery’s last for years! Great, isn’t it?

Transmitted messages are received by a gateway, processed and stored in a database. Data can be shown on a website and even in online “live” graphs depending on the needs.

BeeMonitor with custom front

For example, some temperature & humidity data from one of our beehives:

Battery life:

The prototype has been up & running, collecting data for about 2 months now. So far the battery voltage has dropped from 3.17V to 3.12V without any (low power) software optimisation. Even without the battery will keep the BeeMonitor up & running for a very long time, all the way down to 1.9V. That’s when the voltage reaches the minimum operation voltage for some of the hardware.

Power consumption:

Measuring one wake-up cycle (about 2 seconds) gives a clear overview of the power consumption of the hardware. A short description of how things work here (reference: 1 mV = 1 mA):

  • 0 s: External input, interrupt or timer waking up a part of the hardware (50 nA)
  • 250 ms: Power enabled to other hardware (1.8 mA)
  • 320 ms: Microcontroller startup, bootloader (3.5 mA)
  • 1.7 s: Microcontroller running program, reading sensors, processing
  • 1.82 s: Sending message (50 mA)
  • 1.83 s: Waiting for ACK from gateway (18 mA)
  • 1.85 s: Blink green led (4 mA)
  • 2 s: Powerdown (35 nA)

This graph makes clear I need to optimize the bootloader, because it takes 1.38 s! Thats way to long for battery powered hardware.

Future plans:

There are some improvements needed such as an optimized bootloader, optimized software for better battery life, ..

September 2017: The prototype has been upgraded, read more about the plans & upgrades here.

LoRaWAN IoT Node

 

Past few month’s I’ve been researching and testing with LoRaWAN networks.
After some good test results I decided to developed my own compact, fully Arduino compatible LoRaWAN Node and also develop use cases with them. When developing this hardware it was almost impossible to buy the RN2483 LoRaWAN modules from Microchip. That’s why I chose for RFM95W LoRa modules from HopeRF. Not a bad choice after all, the hardware is very impressive!

The “TvB Wireless Node”, not just another LoRaWAN node:

LoRaWAN Node

 

Bottom side

Features:

  • Atmega1284p with 128kb program memory, running on 8 MHz with Arduino bootloader
  • Supports all RFM95-98 LoRa tranceivers
  • Supports regular tranceivers of the RFM69 series. The RFM69-W, -HW and -HCW versions are compatible.
  • SMA + U.FL antenna connectors
  • Breadboard compatible header pins for easy prototyping
  • 3.3V onboard regulator
  • Red & blue onboard led
  • JST battery connector
  • Battery voltage measurement
  • Reset button
  • Programming header for (CP2102 or FTDI) USB to serial programmers

The microcontroller has more than enough program memory for the LMIC stack for LoRaWAN and other functions. Beside that this module can also be used as point-to-point communication with LoRa (without using an LoRaWAN network) or with regular 433/868/915 MHz transceivers (RFM69).

You get all these options on a tiny 41 x 23 mm board with both U.FL and SMA antenna connector options!

Bare PCB with Atmel1284p and resonantor

Oh wait, when I said “tiny”, just compare the node with the SODAQ Mbili development board for LoRaWAN. It’s just a little bigger than Microchip’s RN2483 LoRaWAN module.

SODAQ Mbili vs. TvB Wireless Node Rev. 3

Easy prototyping

A LoRaWAN node is nothing without easy prototyping options. This one is breadboard and prototype PCB compatible! All main data lines are available with enough digital I/O’s and ADC pins. All you need!

TvB Wireless Node - Proto PCB

Or just directly connect a battery for your mobile application. All types of battery’s can be used with a maximum input of 6V DC. The LDO voltage regulator guarantees a stable 3,3V power supply, even for voltages as low as 3,45V! This makes the use of single cell li-ion battery’s ideal without damaging the transceiver.

TvB Wireless Node - Battery

Use cases

Developing a small or portable LoRaWAN application? No problem for this hardware. Here are some examples where I used my LoRaWAN node for.

TvB Wireless Node - Window

Open door detector

TvB Wireless Node - Collecting sensor data

Battery powered outdoor data logger

TvB Wireless Node - Industrial IoT

Industrial LoRaWAN application with 230V power supply

TvB Wireless Node - Thermocouple and LCDMeasuring high temperatures with a thermocouple, displaying temperature on a LCD screen and transmitting over LoRaWAN

TvB Wireless Node - LoRaWAN GPS tracker

A portable GPS tracker, can also be used for measuring LoRaWAN coverage & range

Next project?

Connecting and digitalizing our beehives with LoRaWAN, and in the far future maybe tracking the flight path of our bees? 🙂

TvB Wireless Node - Beehive

Pinout

Back to the technical side, this pinout diagram shows all features of the module.
TvB Wireless Node Rev.3 - Pinout

TvB Wireless Node Rev.3 - Legende

Programming

The Atmel microcontroller provides awesome support for Arduino. The Arduino bootloader on the microcontroller together with the custom board in Arduino IDE make it very easy to direct upload sketches into the node with just one click. This makes prototyping and developing a whole lot easier.

Chose board small

The custom board

Chose example small

Included example programs

Results

Testing with my LoRaWAN GPS tracker revealed the range goes up to 18.6 km (default 1/2 wavelength antenne on the node). That’s a very impressive range!

 

 

Future upgrades?

  • Adding charging circuit for li-ion batteries
  • Adding voltage polarisation & overcurrent protection
  • Low power features