Brood Chamber & Environmental Monitoring

Temperature and humidity inside and outside the hive are important indicators of hive health. A design for an environmental monitoring system is proposed able to log temperature and humidity inside the hive brood nest and measure temperature, humidity, and solar activity outside the hive. The goal is a monitoring system that can be built for around $100.


Homeostatis is a property of animals in which they regulate their internal environment and maintain a stable, constant condition. If your temperature deviates more than two degrees from 98.6 degrees Fahrenheit then you can be pretty sure that there is something wrong with you. The same applies to bees.

Like us, honey bees are warm-blooded or homeothermic animals. As they evolved, they have expanded their native range from tropical regions into cooler temperate regions by accumulating an energy source during the warm growing season (fat in mammals, honey in bees) then converting that energy into heat during the cold winter season. By surviving the winter, honey bees can increase their colony earlier in preparation for 1) Spring nectar flows and 2) the reproduction of the entire colony early enough to enable the swarm to gather energy to survive the next winter..

Mammals shiver to generate heat. Likewise, some worker bees have a role as ‘heater bees’ [TAUT2008] that can dislocate their wings from their flight muscles and flex those large flight muscles to generate heat. These heater bees are easily identified in images taken by heat sensitive cameras because the temperature of their thorax can reach over 109 degrees! This contrasts with the normal temperature of the brood nest of 92-98 degree Fahrenheit. Even when the temperature outside is below freezing, the center of a healthy hive can be 92 degrees.

If the outside temperature falls below 54 degrees F., bees cannot fly and they will be confined to the hive. If the bees either run out of honey or it is so cold that they cannot crawl from the edge of their warm cluster to the honey (below 50 degrees F, they cannot move), they will starve or freeze.

Cooling in the hot summer is just as important. Wax softens if the hive temperature exceeds 93.2 degrees Fahrenheit. Beside structural problems, this negatively impacts vibration-based communication between bees inside the dark hive[TAUTZ2008]. In the hot summer, mammals sweat and pant to cool off. Bees collect water, spread it over the comb, encourage evaporation by mechanically creating air currents inside their hive to cool it down. In both cases, the evaporation of water into vapor provides cooling.

Research [FERR08] suggests that temperature of the hive increases immediately before a swarm occurs and drops below ambient temperature at the time of the swarm itself.

Humidity inside the hive and outside can influence how quickly the water in nectar is evaporated and transformed into honey. It may also indicate environments that favor fungal (Chalkbrood) growths that can devastate hives.

The prediction of when flowers bloom (nectar flows) is more accurately estimated by counting the number of sun-days than by looking on a calendar. Solar activity also indicates how many days bees have available to forage for honey.


There are several challenges to creating a $100 brood chamber and environmental monitoring system:

  • Existing hobby weather stations cost several hundred US dollars.
  • Cost is not a primary concern here. Since the point of this is to gather information on honey bees and – at this point – we don’t know what we don’t know – the system should be infinitely configurable with various sensors, expandable, and software re-programmable.
  • Bees like to plaster foreign objects in their hive with propolis (bee glue made from plant resins). A humidity sensor needs to be fully exposed to air currents inside the hive.
  • Bee hives are commonly situated where electricity is unavailable. The most common source of energy is the sun.
  • Bee hives may not be visited but once every 2 weeks (some beekeepers have a life). However, to identify swarming, one will need to make hundreds of measurements every day. If 5 measurements (temperature, inside & out, humidity, inside & out, and solar) are made every 5 minutes, you will have 20160 measurement in a 2 week period. Those measurements need to be stored between visits.
  • How can one turn so much data into something meaningful?
  • In the future, a wireless connection would enable real-time monitoring possible. Though total system cost would not be under $100.

Prior Art

There have been several research projects that embedded thermocouple in bee hives in order to measure temperature. The University of Montana is assigned a US Patent 6,910,941 granted on June 28, 2008 for a “Honey Bee Monitoring System for Monitoring Bee Colonies in a Hive”. If there are any patent attorneys out there, I would like to know what ideas in this patent are original and deserving in this patent of receiving a US Government-appointed monopoly. The only good news here is that individuals can legally build their own bee monitoring systems – patents be damned – as long as they do not receive money for using the “patent protected” technology.

There are commercial weather monitors that could be hacked and some are inexpensive. However, I am unaware of an internal hive and external environmental monitoring system that approaches $100.

Microcontroller Design Concept

A $100 system is feasible considering the following developments:

  • A battery powered Arduino computer with an SD flash card can be purchased and programmed for under $50.
  • A networked, one-wire temperature and humidity sensor can be had for under $20
  • By embedding a wooden frame in the middle of a brood box frame that is covered by a fine brass wire mesh and which is sized to respect bee space, it is possible to embed temperature, humidity, and acoustic sensors that share air currents with the bees.

About the Arduino


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Your laptop has a microprocessor in it – probably made by Intel or AMD. Your phone, mp3 player, digital camera, refrigerator, TV, and toaster all have microcontrollers in them from a variety of companies that you probably never heard of. Your car has several microcontrollers. Microcontrollers are low power and cheap digital processors and they are everywhere. It’s about time that bee hives got a microcontroller.

For $30 you can purchase a Arduino Duemilanove which includes a ATMega328 microcontroller, flash memory, bootloader, PWM output, analog input (10-bit analog to digital converter), and binary input/output on a circuit board whose design is open source. There are additional ‘shields’ or application circuit boards that plug into the board below and form a stack. One of those shields is an SD card reader and writer.

I chose the Arduino over other microcontrollers (Basic Stamp, PICAXE, etc.) because:

  • It is inexpensive and available from multiple sources (see Resources).
  • It is open source. Don’t like it? Change it yourself.
  • There is a lot of open source software available including an easy to use programming interface

Progress to Date

I have built a special hive body frame to protect the humidity and temperature sensors yet to allow the free exchange of air. This is described in Section 2 of the Acoustic Analysis project.

I have built the external sensor body out of a 4″ diameter section of plastic pipe. It is topped by a plastic end cap which is itself topped by half of a ping pong ball. This ping pong ball acts as a light diffuser and protects the solar sensor. In side the body is the circuit card for the temperature, humidity, and solar sensors. I have tested all sensors using Java one-wire networking software.

I am in the process of programming my cute little Arduino. It has a flash shield for storing logged readings.

Testing the Arduino, Flash shield, & One-Wire Network

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To be continued.

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