Vultures are nature’s garbage collectors, helping the environment by consuming dead animal carcasses. In this way, they are essential in stopping the spread of diseases such as rabies (which vultures are immune to). However, recent years have seen the number of vultures decline, particularly in South Asia, where some species are close to becoming extinct due to the toxic effects of a drug used to treat cattle. To protect vulture populations, one of the things we need to know more about is their breeding behavior.
A year ago we at Microduino were approached by the International Centre for Birds of Prey (ICBP) as part of a project to achieve this end. The ICBP needed to create an electronic egg to monitor vulture nests. The conservationists there wanted the egg to include a host of sensors that could measure both its internal temperature and the temperature gradient across its surface, as well as barometric pressure, humidity, carbon dioxide levels, light intensity, and the egg’s rotation and movement. The data would then be transmitted to a relay node and uploaded to the cloud.
Initially, the ICBP had considered building a system around standard Arduino microcontrollers. The agency soon realized, however, that mother vultures would be quite displeased to see an Arduino jutting out from their eggs. The size of the board as well as the sensory and communication requirements made the standard Arduino unsuitable. So the ICBP turned to our system. Microduino makes a family of Arduino-compatible microcontrollers and modules that can be stacked on top of each other and that are just 25.4 millimeters wide by 27.9 mm long.
A real vulture eggshell (top) with a Microduino stack illustrates the volume we had to work with. The stack and sensors are held in place by a wooden enclosure (second from top) and data is transmitted to a relay station (third from top) outside the nest. A cloud server tracks each egg’s data (bottom two images). Photos: Microduino (5)
We decided to separate the system into three parts: a data-collection terminal that would gather and store data and perform some initial processing (the electronic egg itself), a data-relay terminal that would receive and retransmit processed data wirelessly, and a data repository in the cloud that researchers could access.
Our initial plan was to stick all the necessary modules and sensors into a 3-D-printed egg and pat ourselves on the back. However, the ICBP presented us with another logistical challenge: To avoid disturbing nesting vultures, the egg had to be capable of operating independently for 70 days!
Consequently, we reapportioned the division of labor among the three elements of our system: Data processing and storage responsibilities were shifted to the data-relay terminal to reduce the egg’s power consumption.
We then set about building the egg. We built an enclosure from laser-cut wood that would fit within an artificial eggshell. We placed inside the enclosure a Microduino core, a Bluetooth Low Energy (BLE) module, and a multisensor 10DOF module, which incorporates a three-axis gyroscope, a three-axis accelerometer, a magnetic field strength sensor, and a barometer. In addition, there are fourteen DS18B20 temperature sensors that cover the entire inner-shell surface and one SHT21 humidity sensor. These all use I2C connections to communicate with the core. An 1,800-milliampere-hour lithium-ion battery provides power. We then placed the enclosure in the egg, which was fabricated with a selective laser sintering machine using PA2200 nylon. This material has qualities similar to those of vulture eggshells.
Moving on, we built the data-relay terminal by combining a Wi-Fi-enabled Raspberry Pi and a stack consisting of a Microduino Core+ (which uses a more powerful processor than the one we placed inside the egg), a Bluetooth module, a real-time clock (RTC) module, and a weather station module.
The Pi talks to the stack via a custom board that creates a serial interface between the Core+ and the Pi’s general-purpose input/output connector.
The terminal is placed a short distance away from the egg and serves multiple purposes. First, it receives all the data collected from the egg wirelessly via Bluetooth. Second, it monitors the conditions outside the egg with its own light, temperature, humidity, and barometric sensors. Third, the terminal saves all the data from both the egg and its own sensors and stores it in the Pi. When connected to the Internet, the data is uploaded to a cloud server.
After building multiple eggs and data-relay terminals in this manner, we created our own cloud server to monitor the project data in real time. Each egg has a unique ID. Using the information uploaded by the data-relay terminals, we are able to construct a 3-D model of each egg’s surface-temperature gradient as well as display other relevant data in real time.
We are now finalizing the project, and the ICBP will deploy the eggs for field-testing this month. A successful field test would mean we can use this method not only to benefit vulture conservation but also for a variety of other environmental efforts.
Our opportunity to work with the International Centre for Birds of Prey was amazing and eye-opening. Sometimes as we marvel at the cool new technologies that are coming out every day, we begin to lose focus on all the good we can do with our knowledge. We at Microduino would like to egg you on to make a positive difference in the world with all the tools at your disposal!
This article appears in the April 2016 print issue as “Vulture Voyeur.”