Sensor Area Networks (SANs)

[nedb]

(05-31-2013 09:56)davidmbrady Wrote:  

(05-30-2013 20:06)nedb Wrote:  Love the coach "Call for help" concept.

I figure we ought to get a rep point when we order XBee radios. Otherwise, I'm just going to order a couple of 'em today. We'll reel this one in, I can feel it.

--Ned

We can definitely work on that Ned - it'd be especially useful to get a break on the gateway. We'll need a WAN and/or a cellular gateway (CDMA or GSM) of sorts and right now that seems to be where the money is. The data plan is cheap and can be purchased on a month by month basis.

For folks interested, google the "internet of things" or "web of things". Imagine dropping your coach off for a prolonged service period. Imagine sitting in your chair at home and browsing the condition of the bus's batteries, or whether it's plugged in, or whether the genny is running, or if the doors are locked. Endless possibilities!

David, you are true blue

I saw James Gosling talking about his vision of the future for the internet. The theme was "ubiquitous everywhere" -- a world where every thing has an address on the internet. It was mid-1990s, the internet had gone commercial and spawned the dotcom boom, and anything was possible! It was like: Imagine you're getting ready for work, you have a handful of shaving lather but there's no hot water. Your shaving mirror is also an information appliance touch screen browser -- you access the water heater, retrieve the parts list, search for a new heating element in stock, anywhere near your route to work, pay for it securely and opt to pick it up in 45 minutes.

Actually, Gosling was much geekier--the example he gave (that I remember) illustrated how ubiquitous everywhere would be: "Your toaster will be on the internet." It was brilliant

Anyway, I hear you.

I haven't looked at truck/trucker data plans or infrastructure. I imagine it is designed primarily for relaying position and maintenance data back to fleet operations, is that what you're talking? Not a lot of bandwidth needed, and I can see how coach data could be that way too. Monitoring doesn't have to involve security cameras. Providers of 'net access to fleet trucks must be focused on big corridors where trucks are, which might not be good coverage for footloose coaches. Too, trucks are moving, so if there's no coverage where they are, they probably will be soon, so they can store data and transmit when possible. Coaches might get better coverage using a MiFi, considering most coaches probably are not stored (or serviced) in sight of the freeway.

What about packet radio. It could switch on every 30 minutes to send a mesh-generated report to the email gateway via repeater. Repeater density might not be that great either, so coverage remains an issue for that idea.

I saw a tiny new 1-wire temperature sensor for a couple of bucks. Each one is encoded with a unique 16-bit identifier. I thought that might make it very simple to poll the SANduino mesh for all temperature readings. The identifier would be a handy way to keep track of sensor locations, data, status, ... There's an encapsulated version too, waterproof. This kind of sensor tech (available with bulk discount, cheap, miniature, data-friendly) gets my juices flowing. If you barbecued Gosling's future vision and pulled it apart for lunch, it would be like a platter of this generation of sensors, cheap enough for deploying in sufficient numbers to give good resolution, minimal wiring requirements, perfect for matching to latest tiny computers, and making it practical to wirelessly (with cole slaw) mesh and report on a complex system like a coach (on a sub roll).

I ordered Series 2 XBee stuff today. I almost got Series 1 for their easy configuration friendliness, but since the 2 series is newer, I figured it is not a bad choice--the Series 1 is not compatible with the Series 2, but future development of compatible stuff will be based on Series 2 requirements. Must be a lot of demand for the Series 1 features, though, they're widely available for sale on the web.

XBee used to use a shield and be pretty much for Arduinos. Now it looks like it has spread via USB ports to all manner of computers. I splurged on a FTDI cable and a Pro series 60 mW radio, along with an affordable 2 mW radio, a shield kit, AVR programmer, ... The shop was offering a free rPi with orders over $350, but I didn't come anywhere near close to that. Maybe once this SANduino mesh prototype takes shape.

Getting the pieces is the easy part, I know. Taking the time to put ideas into the hardware is a little harder. The book will facilitate that part of it, it sounds like it was written for Series 2 XBee projects. It's an O'Reilly publication, at their prices it should be a lay-flat binding and good paper quality! I've forgotten the title, but the author is Faludi. I'll be doing chat at a distance shortly after the package arrives. Fingers crossed

--Ned

[davidbrady]

Hey Ned,

I'll have to google Goslings talk. I'm sure the video is available somewhere and it's always great fun to see early predictions (mid '90's) proved right or wrong. We know it's real because of the grassroots effort involved. Nothing this big or innovative ever came from a single or set of large corporations. It's folks sitting in their garages tinkering and wiring their houses and motorhomes that bootstraps this stuff, then suddenly, one day, we look around and say, "gosh, how did this come about, who would've thought, there's no economic model that would have supported this...". Ha! LOL

The trucker angle is really where it's taking off in the mobile world (me thinks) and they seem to really be driving the connectivity. Here's a product by Digi that does a lot: ConnectPort X5. I'd like to find a gateway in the $200 range, so the X5 is clearly out of our range, but for a flavor of the connectivity and features available take a look at the ad. Among other things it lists: cellular, satellite, GPS, and Wi-Fi connectivity, and it suggests monitoring operating health, performance, and location, plus more. IOW's the trucking world is doing it and they're doing it now and their solution is feature rich.

What we need to do is make it cheap, spin our own sensor network to control and monitor what's important to us, and provide a web content management service to let folks participate in a turn-key fashion.

[nedb]

(06-01-2013 11:09)davidmbrady Wrote:  It's folks sitting in their garages tinkering and wiring their houses and motorhomes that bootstraps this stuff, then suddenly, one day, we look around and say, "gosh, how did this come about, who would've thought, there's no economic model that would have supported this...". Ha! LOL

Exactly what Gosling reported. The big problem with ubiquitous internet was he could find nothing on the market to serve as his information appliance. The test was "Would a doctor carry it around and use it?" The solution, he found, is "hammer technology"--you find something that has a feature you want, and you extract it. With a hammer. Clean it up and use it in your own design. He was unstoppable. He developed Java to run this device. Talk about 'out of the box'

Whoa Digi! Comin' on strong!! They approached the vehicle connectivity problem with a hammer, that much is clear. Their gateway is crazy connected--everything a coach could possibly have, from a serial port to J1939 to WiFi, and everything a WAN could possibly offer from WiFi to cellular to satellite. A 7" dipole for the XBee!? This is the Swiss Army Knife of gateways. The RS232 could be adapted to ethernet or USB... A lot of this is available anyway, if you get a router and switch to connect cellular, satellite, wifi, to computers, but when they add the vehicle data bus connection to it, it becomes a completed puzzle for vehicles with that data bus. The price isn't bad for a solution in a vehicle with those connectivity options. This kind of device could turn a lot of vehicles into rolling/reporting sensor arrays--a refit with this tech would make many J1939 vehicles very desireable on the used coach market.

--Ned

[davidbrady]

Admittedly, I may have seen Gosling's prognostications some time ago and some of it obviously stuck.

Isn't it the truth, Digi is doing it and they've been in the forefront since the early 90's. They started out producing terminal servers. We used a lot of them in my days at Cisco Systems. They were founded in 1985 and went public in 1989. What they're doing now with the Connect product family is what we would term "technology agnostic"; i.e., they don't care what the nuts and bolts are as long as there are nuts and bolts, so they equipped their Connect lineup with everything including the kitchen sink. Sorta like the old days in networking when everything was up for grabs. We didn't know in 1989 that it would all distill down to IP over everything and Everything over IP so we built all possible combinations from FDDI, to Token Ring, to ATM, to Ethernet, and that's just the physical and datalink layers. If you recall, it wasn't that long ago when Novell NetWare was major contender competing against the TCP/IP protocol suite which has now dominated the Internet. In the old days (circa 1989) we'd build dual-stacks into our products to handle both NetWare's IPX/SPX and TCP/IP because we didn't know which one would win out - we were technology agnostic. In five years from now there will be a clear winner in the M2M market and companies like Digi will either simplify and consolidate their product lines or give way to newcomers. Till then it's a rich playing field reminiscent of the good old days!

[nedb]

(06-01-2013 23:38)davidmbrady Wrote:  Admittedly, I may have seen Gosling's prognostications some time ago and some of it obviously stuck.

Maybe at a brown bag lunch talk. His pedigree was something like Carnegie-Mellon (PhD) to Bell Labs, then on to the Valley and Sun, then a lot of grief with Google, Oracle, ....

Quote:What they're doing now with the Connect product family is what we would term "technology agnostic"; i.e., they don't care what the nuts and bolts are as long as there are nuts and bolts

I overheard a guy yelling at work one day. His office was next to mine and he never shut his door, 'tho he always seemed to be in conversation. On this particular day he was obviously on a difficult phone call with someone he took for a moron. When he finally lost it, the whole hallway hjeard him yelling into the phone, "Look, don't give me all this religion. I just want the data!!"

Agnostic, hahaha

Quote: In five years from now there will be a clear winner in the M2M market and companies like Digi will either simplify and consolidate their product lines or give way to newcomers.

This is worrisome in the vehicular sensing market. While CAN is a standard to build on, the products seem to come out of silos where they aren't aware of parallel efforts in related markets. Here's a cute wireless sensor net for boats. Do you think they are remotely aware, with their proprietary NMEA standard, of the RV market? I gotta wonder why no open standard has blown them out of the water yet?

http://www.digitalmarinegauges.com/seasmart.html

[davidbrady]

Guys,

Here's a sampling of what's available in terms of M2M data plans.

The first plan listed at the top is 1MB per month for 3 months at a cost of $12.99 or $4.00 per month. That's CDMA over Verizon and Sprint.

We'll learn as we go but I'm thinking that we only need a few hundred Kilobytes per month. This should do just about everything except full motion video.

Today I purchased a Digi W21 Transport Modem with Gobi by Qualcomm which provides a software configurable cellular connection for both GSM and CDMA networks. This will connect to AT&T, Verizon, and Sprint networks, etc, and it also supports XBee device networks.

[nedb]

(06-03-2013 20:01)davidmbrady Wrote:  Guys,

Here's a sampling of what's available in terms of M2M data plans.

The first plan listed at the top is 1MB per month for 3 months at a cost of $12.99 or $4.00 per month. That's CDMA over Verizon and Sprint.

We'll learn as we go but I'm thinking that we only need a few hundred Kilobytes per month. This should do just about everything except full motion video.

Today I purchased a Digi W21 Transport Modem with Gobi by Qualcomm which provides a software configurable cellular connection for both GSM and CDMA networks. This will connect to AT&T, Verizon, and Sprint networks, etc, and it also supports XBee device networks.

Smart choice with SIM, very pro features. M2M data plans aren't for web browsing, but when you spring for a Digi Transport modem, you're not thinking movie times or restaurant review anyway.

I want to see your wiring closet.

--Ned

[davidbrady]

Thanks Ned,

We're going to launch this project!

I've looked around at D-Link, Linksys, Lantronix, and others and I'm really hooked on Digi and especially their iDigi Device Cloud. The WR21 is the most affordable in their lineup if you want the Gobi module, which I think we do. I bought it from Express Systems and Peripherals in Jackson NJ for $375 plus $10 shipping. Now we need to figure out a sensor feature set; i.e., what are we going to monitor and possibly control. We probably need to have phase 1 thru 3!

[nedb]

(06-03-2013 21:55)davidmbrady Wrote:  We're going to launch this project!
We probably need to have phase 1 thru 3!

With coaches as a hobby, there's always a slant toward problem solving. Bizarre critters are spawned at the intersection of this vast array of tools and techniques at hand when coach hobbyists target a problem from the road/retiree lifestyle.

I think we should keep this in the hobby domain, without leaping to business or productizing. Not yet. Lets just build the object, with the attributes and methods we can think of, and then let nature get carried away with the myriad ways to use it. Doesn't that make sense?

That said, I think some hall effect sensors and LED displays will be in my next order. And a logger, of course

Three phases, foof. We'll get there putting one knee in front of the other.

[davidbrady]

Just a quick update on what I've recently discovered.

First, the Digi WR21 Cellular Router that I bought for $375 (plus $10.00 shipping) doesn't contain a ZigBee Internet Gateway as I initially had thought. This means another small box is required, the Digi ConnectPort X2 which costs $108.

On the plus side, EmbeddedWorks, the same folks who offer affordable byte size chunks of GSM and CDMA bandwidth carry a comparable router for less money and they offer group buys.

Another interesting tidbit is that the discovery of ZigBee Internet Gateway (XIG) devices requires client side connection initiation. This is because we're transmitting over the cellular network. To keep an XIG active and connected periodic keepalive messages need to be transmitted. If not then the device looks like it's disconnected from the network and the server can't find it. I think TCP keepalives are used and the total packet overhead for a keepalive exchange is 114 bytes.

Well if you do the math you can see that a keepalive sent every 5 minutes will consume almost 1 MB of bandwidth per month! Ouch! No big deal really. We have two choices, buy more bandwidth and/or decrease the keepalive frequency.

Putting one knee in front of the other...