Ultraviolet Radiation is involved in many biochemical processes, in the case of human beings in the production of vitamin D and melanin, but overexposure may result in highly harmful effects, such as erythema, sunburn and even skin cancer. For this reason Libelium has recently integrated an Ultraviolet sensor in the Waspmote platform to control the UV Index which may be harmfull for humans.
The new Waspmote Agriculture Sensor Board enables up to 14 environmental parameters to be monitored in a wireless sensor network. This sophisticated monitoring brings extreme precision to crop growing in vineyards and greenhouses by enabling irrigation and climate control to be matched to local conditions.
There are two main ways of performing outdoor location when tracking sensor devices in a large area such as a city. The most extended is using a GPS module to get the information sent by the satellites on the 1575MHz band and extract all the information possible (latitude, longitude, speed, direction). However, this methodology is not effective when requiring mobile scenarios where the nodes can change from a clear environment to an indoor one, such as going inside buildings, garages and tunnels. For this cases we use the information provided by the Mobile Phone Cells (Cell ID, RSSI, TA) which is captured by the GPRS module. Read the complete article.
ZigBee sets three layers of security, the first one is based on the IEEE 802.15.4 Link layer encryption. The others are implemented in the Networking and Application layers. All of them uses AES 128b as encryption mechanism but differ from the kind of authentication and privacy policies. Read the complete article.
During the research of the Waspmote sensor platform, several tests were made using different kinds of transceivers according to the frequency bands (2.4GHz, 868MHz and 900MHz) and the transmission power (1mw, 100mW, 315mW).
The tests performed in the Monegros Desert (Spain) had the purpose of seing the capabilities and limits of the 802.15.4/ZigBee radios integrated in Waspmote.
Among the 6 different links (356m, 639m, 1239m, 3810m, 6363m,12136m) were chosen Line of Sight (LOS) and Non Line of Sight (NLOS) configurations which were tested always using omnidirectional antennas (2dBi, 5dBi). Read more.
As pointed in the previous article 802.15.4 vs Zigbee, the IEEE MAC layer implements several features which are used by the Zigbee protocol in the network and application layers. One of this features is the security services. IEEE 802.15.4 sets the encryption algorithm to use when cyphering the data to transmit, however, the standard does not specify how the keys have to be managed or what kind of authentication policies have to be applied. These issues are treated in the upper layers which are managed by protocols such as ZigBee.
The ZigBee/802.15.4 USB pen drive created by the Wireless Sensor Network Research Group (WSNRG) and the Libelium team is currently being used as an access point to Wireless Sensor Networks when using PDA's and mobile phones. If you PDA or mobile phone has a USB (or mini-USB connector) you can also get your sensor information directly on your hand.
Regarding the 802.15.4 vs ZigBee article, it is important to know which module in the market fits better our requirements and how they behave. In this article we analize the Freescale and Ember radio chipsets integrated inside the Digi XBee modules and their compatibilities and uncompatibilities.
Can a modulation radio be ZigBee certified? What does a communication module mean to be ZigBee compliance? What should I do to get a ZigBee certified sensor device? These and other questions answered in this article.
Since the first ZigBee release in 2004, two revisions (ZigBee 2006v and ZigBee-Pro 2007v) have seen the light. This article comes to explain which are the improvements and changes which have been done to the initial version during the last 4 years.
The MicroSD module for Arduino is a small shield that you can connect to Arduino, once the shield is connected, you add SD flash memory to Arduino. The SD socket is connected to SPI port.
With this module you can store a big amount of information (1Gb microSD card is included).
One of the main challenges when treating the objects and people location field is when they have to be found indoor. We have created a new device called X-Tick as a tool to let the creation of triangulation applications based on the RSSI parameter computation.
When monitoring risk situations it is important to be able to generate alarms in real time and in the same place where the parameter is detected. For this scenarios the ideal solution is to send a SMS directly to the secutity forces such as fireman brigade or policy. This article shows how to use the GPRS/GSM communication module for SquidBee and configure it to send SMS's in the same time it happens.
Wireless Sensor Network use normally IEEE 802.15.4 / ZigBee technologies for communication among motes, technologies like these are very useful to tramsmit data between motes. But some times in Wireless Sensor Network is interesting to count with a long range communication technology to send / receive data to a remote user, server or alarm center. Using the cell networks throught the GPRS/GSM module we are going to make our motes be able to work and send information in almost anywhere.
People often get confused with all the communications technologies which are used in the WSN field: 802.15.4, ZigBee, Mesh protocols, 2.4GHz, 868MHz and 900MHz bands... This first document compares both IEEE 802.15.4 and ZigBee technologies and explains its main characteristics.
SquidBee is a wireless sensing mote which simultaneously measures temperature, relative humidity and intensity of light and wirelessly sends data to a central monitoring Gateway. This tutorial is intended to provide a quick assembly guide for those who want to build a SquidBee through easy construction steps.
Here we have the classic presence detector built in a SquidBee mote. We use a PIR sensor integrated with an on-board circuitry and a Fresnel lens, suitable for detecting presence from anything emitting infrared radiation up to a distance of 6m, and connect it to a wireless emitter in order to receive the corresponding alarm. The mote is also prepared to remain in a low-consumption state, resulting in a perfect device for battery-powered applications.
We have developed a SONAR mote for detecting presence and measuring distances up to 6.45m. It is constructed from an integrated ultrasound sensor placed into a SquidBee mote which wirelessly outputs range values whenever there is any moving object within the monitored area.
In this article we are going to show how to improve a SquidBee mote adding GPS position using the GPS module from Libelium. To the three usual sensors (temperature, humidity and light) now we add the physical position as a sensor. With this improvement into the motes our sensor network is able to provide the coordinates of each node in real time.
