Public Health is the science and art of protecting and improving the health of communities through education, promotion of healthy lifestyles, and research for disease and injury prevention. Public Health helps to improve the health and well being of people in local communities and around the world. The dramatic achievements of Public Health in the 20th century have improved our quality of life: an increase in life expectancy, world wide reduction in infant and child mortality, and the elimination or reduction of many communicable diseases. Today, Public Health leaders continue to strengthen their roles as advocates for improved population-based health in an international, global community.
Fig. 1.- Health expenditure as a share of GDP, EU 27
These achievements have been possible thanks to new medical devices, medical drugs and vaccines that allow to prevent from diseases or fight against them. As we can see in Figure 1, European Governments are increasing Health budget every year. Furthermore, the same happens with other countries all over the world. Different organizations have been created to control Health and drug administration such as World Health Organization (WHO), U.S. Food and Drug Administration (FDA), American Public Health Association (APHA) or European Medicines Agency (EMA).
Local governments and these global organizations are responsible for drug regulation and control in order to preserve them properly. Pharmaceutical companies sell their medicines all over the world and cold chain is required to be followed to maintain them fit for consumption. French Health Security Agency (AFSSAPS) or Spanish Medicines Agency (AEMPS) follow the European directive and establish the conditions at which each drug needs to be stored.
Medical drugs are very expensive, in special vaccines and others that need to be stored at a specific temperature. Therefore, real-time monitoring is vital to control whether the cold chain has been broken or not. Wireless sensor networks (WSN) are capable of getting temperature, humidity or luminosity measurements and transmit the data to a remote server periodically. In this way, real-time conditions can be monitored in order to know when a problem in a freezer or a refrigerator happens, avoiding critical situations and saving a huge amount of money.
ARES system has been developed by DeltaZ, a Malaysian company focused on medical products, which has been deployed in several cities in Malaysia. The system is able to monitor several parameters (Oxygen, CO2, Vibration or Temperature among others) in different environments:
Fig. 2.- Project location
The proper methods of storage and preservation of drugs and their preparations are of very great importance for maintenance of their potency. These methods must be strictly observed by the manufactures and retail pharmacists.
The following factors may affect the drug:
ARES project allows to monitor all these parameters in order to check the drugs are stored in the correct conditions.
This project can be better explained with the following diagram:
Fig. 3.- Solution diagram
More than 50 Waspmotes have been deployed in several locations; measuring different parameters:
These sensors are connected to Waspmote through the Gases Sensor Board, which contains the electronics needed to implement an easy hardware integration of these sensors.
Fig. 4.- Waspmote Gases Sensor Board
The amplification stage of each sensor is trimmable, to allow a better integration of the specific sensor, as there can be variations from one sensor to another one of the same model. Moreover, this characteristic allows us to focus the accuracy of Waspmote in a region of interest. Besides, it is possible to switch each sensor on separately, as their power supply lines are independent and can be controlled by Waspmote in real time.
In order to know where this sensor is located, each Waspmote can integrate a GPS, that delivers accurate position and time information.
Libelium offers several wireless modules for the radio communication:
Fig. 5.- Waspmote Gases Sensor Board
So we can reach up 40 km with Line of Sight (LOS) condition using the 868MHz module. The high performance of Waspmote makes the readings really accurate and the transmission is highly reliable and flexible.
It is also possible to transmit the data via GPRS, as a secondary radio module for better availability and redundancy in situations when it is critical to ensure the reception of the message. The GPRS module is quad-band (it can operate in 4 different bands, so it supports any cellular connection provider), making it able to work all over the world, therefore this project we are describing is suitable for any country.
One of the main characteristics of Waspmote is its low power consumption:
Waspmote is sleeping most of the time, in order to save battery. After some minutes (programmable by the user), Waspmote wakes up, reads from the sensors, implements the wireless communication and goes again to sleep mode. Each device can be powered with rechargeable batteries and a solar panel, making the system very autonomous.
For an accurate measurement, sensors have been calibrated in professional laboratories in order to provide the best results in this project. On the one hand, one of the biggest problems faced in this project has been related to sensors calibration. On the other hand, as the nodes are forming a mesh network, many tests have been carried out to determine the best location for repeaters.
Waspmote, Gases Sensor Board, Sensors and battery were placed inside an enclosure to be able to be set on the refrigerators. End devices send the sensor data every hour and sleep the rest of the time in order to save battery. Repeaters are powered all the time to be able to route the packets and maintain the network alive.
Fig. 6.- DeltaZ device which contains Waspmote
Once the sensor nodes have been validated by a large number of tests, they were deployed in several hospitals in Malaysia.
Fig. 7.- Waspmote placed on the Hospital's walls to repeat the signal
Sensor nodes make measurements and periodically send the results to the server application for further analysis and database storage. Web application collect information from the nodes and perform their visualization.
Fig. 8.- Web application for monitoring refrigerator parameters
End devices, the nodes on the refrigerators, are powered by a lithium battery. Taking advantage of Waspmote's saving energy features, these motes have battery life up to 16 months. Repeaters are powered all the time to repeat the packets, so no maintenance is required for them.
As a result of this project, storage conditions in medical refrigerators can be monitored in real-time, saving time and money and thus, avoiding to break the cold chain, what would lead to huge economic losses.
If you are interested in Waspmote, we will be glad to help you to design your system. You can request for a quotation of Waspmote here.