What happens when the grid breaks? Communications need to be restored.
After Hurricane Katrina hit, BellSouth announced that it would take 3 months to restore phone lines. Volunteers using WiFi gear were able to connect churches and community centers within the first weeks and within three days of setting up an asterisk call server, routed 10,000 phone calls. Reliable backup infrastructure can be brought up in hours or minutes if you are prepared and have a plan in place.
Here is a plan for a mobile mesh repeater node to be used while you are setting up permanent installations, doing site surveys or for completely mobile teams.
After Hurricane Katrina hit, BellSouth announced that it would take 3 months to restore phone lines. Volunteers using WiFi gear were able to connect churches and community centers within the first weeks and within three days of setting up an asterisk call server, routed 10,000 phone calls. Reliable backup infrastructure can be brought up in hours or minutes if you are prepared and have a plan in place.
Here is a plan for a mobile mesh repeater node to be used while you are setting up permanent installations, doing site surveys or for completely mobile teams.
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Spool of Cat5e: I always use red to announce that there is power running through it.
Crimpers and Connectors: Even though it's wireless, you always need to use *some* wire.
Backpack or messenger bag: The orange bag pictured is a waterproof backpack/messenger that I got as a promotional item, Any durable, rubberized bag will do the job.
Power Source: I use a sealed lead acid Hawker Genesis 12V 16Ah. You can use any 12V battery, but it's important to pick something up with long life and low weight. Having an easy to find charging system is also a good idea.
Mesh Node: We are using the Metrix Mark II Kit here. Running Pyramid Linux, it can act as an access point, a client, a mesh node, and more. Being waterproof is also a nice touch.
Antennas: Whips are nice, but they don't go very far, For this setup, we've got an outdoor 8dbi omni and a small 10dbi patch antenna. This allows us to set up a directional link to our upstream node while serving clients locally. Picking your antennas really depends on how far you're going to advance and what you can carry. If you're using this as temporary infrastructure while setting up permanent installations or using it as site survey equipment, I recommend matching them with your standard kit. If you are only doing temporary sites, the above combination is pretty flexible. Both of these antennas were picked up at HyperLink
Crimpers and Connectors: Even though it's wireless, you always need to use *some* wire.
Backpack or messenger bag: The orange bag pictured is a waterproof backpack/messenger that I got as a promotional item, Any durable, rubberized bag will do the job.
Power Source: I use a sealed lead acid Hawker Genesis 12V 16Ah. You can use any 12V battery, but it's important to pick something up with long life and low weight. Having an easy to find charging system is also a good idea.
Mesh Node: We are using the Metrix Mark II Kit here. Running Pyramid Linux, it can act as an access point, a client, a mesh node, and more. Being waterproof is also a nice touch.
Antennas: Whips are nice, but they don't go very far, For this setup, we've got an outdoor 8dbi omni and a small 10dbi patch antenna. This allows us to set up a directional link to our upstream node while serving clients locally. Picking your antennas really depends on how far you're going to advance and what you can carry. If you're using this as temporary infrastructure while setting up permanent installations or using it as site survey equipment, I recommend matching them with your standard kit. If you are only doing temporary sites, the above combination is pretty flexible. Both of these antennas were picked up at HyperLink
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A part of my job is developing and using rapid deployment networks for things like disasters. All too often your temporary setup becomes longer term as workers come to rely on it.
There are three things that will improve your setup. The first is the ability to power it in the field without any supporting infrastructure. This is a particular favorite of mine for that application
http://www.tyconpower.com/products/files/TP-SCPOE_Charge_Controller_Spec_Sheet.pdf
They're not that expensive and they'll manage the power for you. It also provides a port to plug in and configure the radio locally if needed. You will need to size your battery to run roughly for 24 hours without power. If you add some good folding or rollable solar panels with enough output to charge during the day you have a reserve for cloudy days. A small wind turbine is also handy. The charging unit provides inputs for both.
The second thing is to get rid of the bag and place it in a pelican case. You can mount the radio board, charge controller, and battery all in the case and drill some and waterproof the ports for the antennas. Their are waterproof connectors for charging and Ethernet as well.
The last is a little extra protection for the electronics. Things will leak, condensation will form, and you need to be prepared for it. Two products we frequently use is Corrosion X and Boeshield T-9. You can spray down the electronics with Corrosion X and it'll waterproof the boards. It's non-conductive so make your connections before you treat the board. The Boeshield we use primarily in cold environments where we expect ice to form.
We use Routerboards and Ubiquiti a lot in our setups. They're inexpensive and work well. We have different setups for different situations but they're all simple and rugged in design.
We stay away from mesh setups. If you have mobile nodes it's applicable but most of the time our links are static and the network is designed to be flexible and easy to deploy in the field.
Good luck with the design!
1) You didn't install any sort of protection for this device, I would highly recommend a voltage regulator to supply the unit with the correct amount of current and voltage. This will prevent spikes such as those that would occur from charging.
2) Installation of inline fuses is a must for this type of project.
3) How do you plan on charging the battery? This will probably run somewhere around 5 days depending on data usage with this size batter. Why not install a small solar collector as well?
4) Antenna above AGL is a must for something along these lines to have good coverage. This type of packaging doesn't really support this. Why not a pole mountable box? Mount it to the side of a telephone pole, lamp post, set it on a tripod, etc...
5) Finally, what is this talking back to? Most Mesh Nets require one or more WAN points. This Instructable does not state whether this is a node, router, or end user application.