Through a series of workshops we will explore the wireless network, its technology, topology, implementation and usability. The series of workshops will be closing with a one week hands-on workshop where the participants will work together building a temporary wireless network, connecting clients to it and sending all sorts of data over the network.
mesh networks workshop: 21-27 january 2008
windpower workshop (DIY): 20-21 february 2008
closing workshop – artmeshnetwork: 19-26 april / st.erme, France
Self sustainable units
The unit(s) will be made self sustainable by the use of solar or wind power and because they are using wireless technology there is no need for any demand of infrastructure on the location(s) where these units will be positioned.
The location of the units is very important for the choice of the alternative energy source that will be used. In Brussels we should defenitely opt for the wind turbine (or a hybird system with solar) while on other locations solar would be a better choice.
Since we have 2 working units (for now), it would be good to rig one with a wind turbine and the other with a solar system.
In the case of a wind turbine the choice of which type of turbine depends on how steady the wind is on the location. When the winds are directional steady a horizontal turbine needs to be used, when there is a lot of turbulant wind a vertical turbine needs to be used.
To explain the reach of an antenna, the metaphor of light (flashlight / bulb / laser light) is used.
Frequency: antennas use high frequencies so they need to see one another.
They are pulse modulated.
The more Watts an antenna receives, the further the reach; although with power comes noise, and the quality of the signal is a ratio of power/noise.
Low frequencies is very onmi-directional and requires as lot of power.
Also the physical size counts: the higher the antenna, the more reach (geometrical shape; material and the way you make it).
Weather conditions: cloudy day; rain: omni-directional antennas are no go; than you need a satellite
dish. Band with of electrical tools as cordless phone or microwave can interfere, and also air pollution.An antenna is like an analog instrument.
Band withs are regulated. 2.4Ghz and 5Ghz are free for experiments.
If you are in the very high frequencies (very directed), you are difficult to trace.
Components for an independent unit
Dedicated compu (12V 1W) P=V.I
80W solar panel â€“ Kyocera
In the margin –> Wind mills
Max speed blades=> 1 blade best, but needs a lot of wind to start.
Also systems to concentrate wind
Low speed wind proof of concept
ready made rooftop turbines for urban settings
More pics by annemie: www.so-on.be/?id=879
Friday 13.07 and Saturday 14.07 we did some handson experiments. We created a dedicated network with 2 grid antennae, one on the rooftop of okno, the other one on the rooftop of so-on.
Both antennae are semi-directional, approx. 120cm wide and 80cm high and are slightly curved.
The transmitter/receiver is adjustable (slide in/out) in a way that the range can be or very narrow in degrees (and reaches further), or slightly broader and than transmitting in a shorter aerea.
Itâ€™s a delicate job (a question of mm) to fix the grid-antenna in the very right angle to the readymade standard (rooftop model).
Both grids are connected to a Linksys WRT54GL router with flashed OpenWRT firmware. The okno-WRT is the master and gives out the IP numbers to the computers connected to this network.
The first day we powered the okno-grid with a solarpanel + battery. The energy of the Velleman-photovoltaic was just enough (270mA) to feed the router, but we had to deconstruct the setup as we did not include a regulator for the battery (we didnâ€™t had one) and thus the setup became to risky to blowup the Linksys (when battery runs out or overcharges).
So finally we connected the 2 Linksys routers to the regular power network. This means that an ugly powercord runs down from the rooftop as far as to be plugged in the nearest power-point inside. The same thing for connecting to the local network via the inside router: an ethernetcable has to be run down all the way.
An urgent next step is: to power the antennae with alternative outside sources and make them self-sustainable and idependent from the regular power-network. A second step is to make them wireless accessible.
Only then we will be able to speak about indepentent and mobile network modules!
The IP address of the okno-grid is 10.30.30.1
The IP address of the so-on grid is 10.30.30.2
When you connect to this network with your computer in DHCP-mode, the okno-grid-router will give you a dynamic IP between 50 and 100.
You can also connect with a fixed IP (for ex. If you work with a dedicated computer or want to send out a fixed url for streaming). Than you have to choose an IP between 10.30.30.101to254
On the local webserver of the computer an index webpage can be setup with all info about whatâ€™s going on.
Follow Up: What to do next?
Workshops for september/december and january/april
Okno Grid Antenna: power supply by sustainable energysource (solarpannel, windmill)
So-on Grid Antenna: idem
Put a regulator for the battery to stop charging when full.
Is it possible to make them wireless accessible? (no ethernetcables animore!)
Make your own antenna dedicated to the needs of a specific project
Make your own windmill dedicated to the needs of your project
Compose your own sensors dedicated to your project
Wireless & Low Power Workshop:
Compose your own dedicated unit and power it by wind or sun:
– Sensors + controllers (ex. Hives or homemade)
– Server (web- and/or streaming-server)