Libelium hardware and competitors (weather station)
Before I introduce you to this new post, which tells some hardware background, I’ll first try recapitulate what Roel and I are working on.
As explained in one of our first posts, we’re building on a Wireless Sensor Network (WSN) that will measure sensors (temperature, humidity, CO2, etc) in several classrooms at Group T. Then, the values will be transported out of our local WSN into a database in the cloud (“IPSUM”, a project from Ruben Tacq)(in the cloud means that it is stored “somewhere on the internet”). As a third part of this thesis subject, Matthias Verhelst is making a web interface to visualize our sensor nodes on Group T blueprints and to read their values. So he takes the values out of the cloud and presents them to the visitors who are logged in on his site. It will for example, as an administrative user, also be possible to change the frequency at which a certain sensor stores its value into the cloud via the web interface.
We have the great honor to work with very expensive sensor nodes developed by Libelium (same manufacturer as the radiation sensor board in our previous post). In the picture below you see a single “Waspmote” (approx.. €150). and one with the battery and gasses expansion board (appox. €120)(here with 4 sensors, depending on what they measure: €2,5 – €49) connected. We also have the agriculture expansion board to connect with our weather station (yes, every student longs to climb on the roof of Group T).
Nevertheless Libelium’s hardware is great; it is interesting to compare them with some competitors. One is Sparkfun Electronics. They also produced a weather board. It is fairly cheaper than our agriculture board and has more connectors on board. A big advantage to our board is that it has RJ11 connectors (the old telephone wires) and thus ensures more stable connection with the weather station. We have to cut the RJ11 connector and connect the wires by hand, hoping they don’t loosen due to one of those severe Belgium snow storms.
So, if everything gets ready in time, teachers and students of Group T will be able to measure the temperature inside and outside, humidity, CO2 levels, wind speed and direction, rainfall, and solar radiation at Group T from wherever they are, on every laptop, tablet, etc.
I realize that in one of our post we’ve told you that ZigBee is very a low-cost technology and now I’m saying we’re working with very expensive hardware. That’s true. But you should take in mind that now we are working with a university lab kit that contains several building blocks. All of them are very extensive so a lot of applications are possible (even combining ZigBee with Bluetooth or Wi-Fi on one Waspmote is possible). For big projects hardware can be made much more specific and thus much cheaper (for example the simple nodes we developed during the first semester only cost about 50 euros, so 1 third of the price of a Waspmote. Also buying 100+ units usually gets you about 20 – 30% off the price.