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:
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.
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.
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.