Topic 5

Development of environment for testing various configurations of 1-wire sensor networks

Introduction:

The FER's skyscraper (C) building is equipped with building automation devices which enable advanced monitoring and control of the building's electrical and thermal consumption. Room air temperature control relies on, i.a., fancoil return medium temperature. Cooling medium return pipe of every fancoil is equipped with a 1-Wire temperature sensor, model DS18B20. The sensors are interconnected using a Cat. 5e UTP cable, and on the same bus is a 1-Wire master module, model ADA401-WP. The name „1-Wire“ is used for a master-slave communication protocol used by digital sensors. Connection reliability and stability depends on cable length, number of sensors connected to a single bus and the bus topology.

Tasks:

  1. Prepare the experimental setup for testing various sensor network topologies. The setup consists of an ADA-401WP master module and its power supply, multiple 1-Wire sensors of type DS18B20, sections of Cat. 5e UTP cable of various lengths and additional accessories needed for connecting and mounting the equipment.
  2. Using the experimental setup, make an exact reconstruction of a sensor network installed on one of the FER's C building floors. Write documentation about the sensor network; draw schematics.
  3. Test the operation of the sensor network. Connect a computer to the ADA-401WP master module using RS-485 communication protocol and address all the sensors on the bus using a specific software tool. Track the communication in order to detect possible problems. If there are communication problems, detect its causes and rectify them.
  4. Try out various configurations and topologies of sensor networks. Find out the operation limits, e.g. cable length and number of sensors connected to the same cable. Derive recommendations for designing new sensor networks and expanding existing sensor networks.
  5. Develop a program that automatically collects measurements from the sensors and stores them into a database. The program shall run on a Raspberry Pi computer, and the database may run on the Raspberry Pi or on a remote server. The master module ADA-401WP shall be used as an interface between the sensors and the Raspberry Pi.
  6. Use a Raspberry Pi as a 1-Wire master module, in order to minimize a number of devices needed for sensor network operation.

Additional information:

  • Number of students: 1-2
  • Work is mostly sequential
  • For graduate students with an interest in hardware
  • Keywords: sensor networks, building automation, 1-Wire, embedded, Raspberry Pi