The BeeMonitor with permanent scale

The BeeMonitor prototype has been up and running sinds march 2017 without any big issue’s, in the mean time some hardware/software upgrades were made. A complete new Arduino compatible Arduino bootloader allows faster startup even at very low voltages.

Because the battery life was very promising I decided to add a load cell for a permanent scale and keep track of the beehive weight. The result is a wireless BeeMonitor + scale without external power or wires. The beehives can be placed everywhere within range of the gateway. Reference measurements indicate the two AAA batteries will keep the BeeMonitor powered for at least one year, collecting data every 15 minutes! Awesome!

Setup: BeeMonitor prototype with internal beehive temperature sensor and permanent half-scale

The scale is based on the half-scale principal. It’s designed to weigh only half the hive, making the design simpler because only 1 (high quality) load-cell is required. This design finally makes monitoring beehives affordable!

There’s a on-the-go calibration procedure. The scale can be calibrated in the field by following a couple of steps, without the need of re-programming.

Temperature graphs

The graph below shows the ambient temperature (outside beehive, shade) vs. beehive cluster temperature (inside beehive). Past days have been mostly wet with almost no sunshine. The cluster temperature dropped a few degrees what probably indicates the queen is laying much less eggs and the bees are preparing for a long cold period.

Ambient temperature (outside beehive, shade) vs. cluster temperature (inside beehive)

Weight graph

A couple of days before the beginning of this graph, the bees were given extra sugar water (the two steep drops in the graph are the removal of the empty sugar water reservoirs).

Due to the bad weather the bees don’t fly much and certainly don’t bring much food in. The weight drops because of the erratic weather, the number of bees is also reducing because they prepare for winter. The weight rises and decreases slightly within one day but the overall weight is decreasing.

The weight is displayed in grams, because of the half-scale design this is only the weight of half the hive. To know the total weight, it has to be multiplied by two. A future software upgrade will display the real weight.

Beehive weight in grams

Future plans

A revision/upgrade of the BeeMonitor is in development. Below the key features of the first version with the most important upgrades in the new version.

Key features

  • Atmega328p microcontroller (Arduino compatible)
  • 2 internal AAA batteries (3V)
  • Powerdown: 35 nA
  • Wakeup every 15′, 30′, 1h or 2h selected with internal dipswitch
  • Beehive ID selected with internal dipswitch (up to 15 hives without re-programming)
  • Low power 868 MHz radio with internal antenna (up to ± 250m), external antenna possible
  • Manual “wakeup” button
  • RGB led
  • Buzzer
  • Internal ambient temperature/humidity sensor
  • 2 RJ12 ports for external temperature/humidity beehive sensors


  • New, slightly larger housing
  • 3 RJ12 ports for temperature/humidity beehive sensors
  • Internal (removable) HX711 ADC module
  • Separate (pluggable) connector for beehive load-cell scale
  • Extra “calibrate button” for easy scale calibration
  • Even lower power consumption
  • Integrated boost converter to operate down to 1,8V

The current gateway is based on a Raspberry Pi, running open-source “Domoticz” software. This is actually home-automation software, because I had this running for other projects I chose to implement the BeeMonitor in Domoticz for the prototype.

Because this is not really a plug & play option for beehives, a new cheaper Wi-Fi, IoT (LoRaWAN) gateway needs to be developed to forward all data to an online platform. Analyzing all available options, seems the best option.

Questions? Don’t hesitate to contact me!

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