|Wireless remote data
Technologies and sample systems that gather sensor data across distances, usually via radio links. This includes general telemetry and SCADA (supervisory control and data acquisition), especially for gathering data about wildlife, natural resources, and distributed energy systems.
Ken Novak's Weblog
Friday, May 28, 2004
What is an AGM battery: Background on absorbed glass mat battery products. In this battery design, acid is completely absorbed into microfiber glass mat separators which are sandwiched between lead plates and typically wound in coils. Advantages:
- totally sealed and maintenance free design
- more heat and vibration resistant
- slower self discharge rate (longer shelf life). A wet battery discharges 15% a month, some AGM batteries discharge only 2-3% a month, so 6 months idle is no problem
Many vendors are online. 2:52:37 PM
Thursday, May 27, 2004
Embedded Linux marches on: "One of the cheapest Linux computers you can buy brand new (not at a garage sale) is the Linksys WRT54G, an 802.11g wireless access point and router that includes a four-port 10/100 Ethernet switch and can be bought for as little as $69.99 according to Froogle. That's a heck of a deal for a little box that performs all those functions, but a look inside is even more amazing. There you'll find a 200 MHz Intel processor and either 16 or 32 megs of DRAM and four or eight megs of flash RAM -- more computing power than I needed 10 years ago to run a local Internet Service Provider with several hundred customers. But since the operating system is Linux and since Linksys has respected the Linux GPL by publishing all the source code for anyone to download for free, the WRT54G is a lot more than just a wireless router. It is a disruptive technology. ..
it isn't what the WRT54G does that matters, but what it CAN do when reprogrammed with a different version of Linux with different capabilities. .. Linksys, now owned by Cisco, not only doesn't mind your hacking the box, they are including some of those hacks in their revised firmware...
Probably the most popular third-party firmware you can get for the WRT54G comes from Sveasoft .. [whose] head techie is James Ewing.. If you have a WRT54G, here's what you can use it for after less than an hour's work. You get all the original Linksys functions plus SSH, Wonder Shaper, L7 regexp iptables filtering, frottle, parprouted, the latest Busybox utilities, several custom modifications to DHCP and dnsmasq, a PPTP server, static DHCP address mapping, OSPF routing, external logging, as well as support for client, ad hoc, AP, and WDS wireless modes. .. The parts of this package I like best are Wonder Shaper and Frottle. Wonder Shaper is a traffic-shaping utility that does a very intelligent job of prioritizing packets to dramatically improve the usability of almost any broadband connection [by prioritizing voice and optionally a particular user's traffic. Frottle also prioritizes traffic.] .. Neither Wonder Shaper nor Frottle are the most elegant solutions, but they work well and they work together on the Sveasoft firmware. ..
The result is a box [that] automatically attaches itself to an OSPF mesh network that is self-configuring. In practical terms, this mesh network, which allows distant clients to reach edge nodes by hopping through other clients en route, is limited to a maximum of three hops as the WiFi radios switch madly back and forth between sending and repeating modes. If you need to go further, switch to higher-gain antennas or gang two WRT54Gs together. Either way, according to Ewing, his tests in Sweden indicate that if 16 percent of the nodes are edge nodes (wireless routers with DSL or cable modem Internet connections), they can provide comparable broadband service to the other 84 percent who aren't otherwise connected to the Net." Cringley then speculates on how to take on phone companies with this. 11:22:56 PM
Codan experience in Guinea-Bissau Elections: "The National Elections Commission of Guinea-Bissau used new Information and Communication Technology tools to coordinate the legislative elections held March 28 and enable poll workers to verify names and identity card numbers on the voter rolls. .. The project was designed by Sila Technologies (SITEC), a private company, and funded by a grant from the European Economic Community.
About a week before the elections, SITEC had up and running high frequency (HF) radio units in all nine regional capitals of Guinea-Bissau and verified that they could communicate with each other via voice, fax, or data transmission over up to 200 kilometers. Fax transmission was reported to be flawless, and voice communication was functional. According to SITEC engineer Amidu Sila, some level of noise is to be expected in using this technology and frequency range for voice, though this never impeded communication. ..
The company chose radios made by Codan Ltd., model NGT SR, for the project, along with a system that automatically selects and switches between available frequencies to get the best transmission. The HF units reportedly cost around $7,000 each, and the additional link management system goes for about $1,200. Before beginning installation, SITEC had to be assigned twenty available HF-band frequencies, which they chose together with the regulatory agency. Half of the frequencies were for use during the day, and the other half for the different atmospheric conditions of nighttime. Sila thinks that the radio could work over distances as far as 1500 kilometers." 12:34:57 PM
: "Relief workers are often encumbered by poor Internet connectivity, fragile or expensive equipment, or security concerns associated with collecting detailed geographic data in areas recovering from conflict. As connectivity expands and the tools get cheaper and more diverse, the specific needs of relief workers in the field are increasingly being met. Companies such as Global Relief Technologies
and Groove Networks appear to point the way." 12:24:53 PM
Wednesday, May 26, 2004
Devices and sensors for watching places like computer rooms remotely. Tracks humidity, temperature, air flow, light and sound levels, doors open/closed, webcam, etc. Sensors with RS232 under $200, packaged with self-contained web site under $400. Similar but more expensive are NetBotz
. 5:15:15 PM
Yahoo! wifi finder:
Directory of wifi locations, including iPass, Boingo, etc. Appears to be US only. Searchable by type of location and distance from a street address. Includes some free hotspots (like public libraries) but doesn't list open access points. 10:20:31 AM
Monday, May 17, 2004
NASA's Advanced Communications Technology Satellite (ACTS)
: 10 years old, the program continues to provide capacity and sometimes, people, to demonstrate new satellite applications. Education in developing countries is one ongoing area. "The Advanced Communications Technology Satellite (ACTS), a significant activity of the Space Communications Program
, provided for the development and flight test of high-risk, advanced communications satellite technology. Using multiple spot beam antennas and advanced on-board switching and processing systems, ACTS pioneered new initiatives in communications satellite technology." 4:27:01 PM
Sunday, May 16, 2004
802.11b wireless flaw identified: ""In order to exploit the vulnerability potential attackers only need a common wireless adaptor which retails for about US$35 and instead of using it to enable their computer to access a network, they can change its coding to interfere with transmission. "With this adaptor you can basically totally disrupt any wireless network that uses this technology within a kilometer of its operation in anywhere between five and eight seconds.".. [Professor] Looi said any computer, PDA or notebook could send out the signal if the wireless adaptor was programmed accordingly. ..
Wireless technology is gaining traction and in some countries is used to control infrastructures such as railway networks, energy transmission and other utilities. QUT's School of Software Engineering and Data Communications deputy head, associate professor Mark Looi said the discovery of the flaw should send a warning to high levels of government and industry worldwide. "Any organization that continues to use the standard wireless technology (IEEE 802.11b) to operate critical infrastructure could be considered negligent," Professor Looi said. "This wireless technology should not be used for any critical applications as the results could potentially be very serious."" 11:11:14 AM
In a Road That's All Eyes, the Driver Finds an Ally: Adding PV cells, LEDs sensors and cameras to road lane markers has many benefits (and could create a mass market for these components). "after perfecting illuminated markers that are embedded in the road surface to guide motorists through bad weather or warn of dangerous conditions, Mr. Dicks's company, Astucia Traffic Management Systems, is going a step further. Its latest creation is an embedded stud equipped with a camera that catches speeders, monitors traffic for criminals or stolen cars and even checks for bald tires on the fly...
illuminated marker would be more visible than a plain reflector, and the idea was that a car passing over the markers would cause them to stay illuminated long enough so that they would provide a warning trail of lights for any vehicles close behind. Working mostly with family members at first, Mr. Dicks produced a prototype marker within two years. He dodged the white L.E.D. problem by combining the glow from red, green and blue arrays. The group not only overcame the limitations of solar cells, but also managed to engineer markers that turned red to warn when the gap between two cars was dangerously small...
Optical systems inside the casing are able to monitor the atmosphere for fog. Electrical resistance detectors can check for standing water. The addition of a thermometer allows the marker to predict ice.
[Now, high-resolution digital cameras inside] the flush-mounted housings [use] a special series of lenses that in effect allow the camera to look upward and forward from its subsurface location. .. Astucia has developed a system that is operating on a highway in Scotland. It employs three embedded cameras to give front, rear and side views of passing vehicles. Other embedded sensors project two infrared beams over the road that are used to time traffic and determine its speed. The images and the speed data travel under the road by cable to a computer. It in turn relays the data by satellite to Astucia's offices. The system is currently being used to monitor traffic slowdowns. When it detects them, it turns on illuminated markers farther up the road as a warning. Mr. Dicks said that its speed measurements were accurate within 0.5 percent, well within the tolerances demanded for traffic enforcement [including catching speeders]. Similarly, he said, the systems can be combined with optical character recognition software to automatically track stolen vehicles or cars believed to be used by suspected criminals..
Mr. Dicks was not the only person with a desire to illuminate to road markers. After a friend struck and killed a pedestrian in 1991 at a crosswalk in Santa Rosa, Calif., Michael Harrison developed a system that uses flashing L.E.D.'s in the road surface to make crosswalks more visible. The company he founded in 1994, LightGuard Systems, now has about 700 installations in the United States. A study of 100 illuminated crosswalks by Katz, Okitsu & Associates, a traffic engineering firm based in Southern California, estimates that adding the blinking L.E.D.'s to crosswalks can reduce pedestrian accidents by 80 percent." 8:55:29 AM
Thursday, May 13, 2004
Stretch Your Signal
: Options for extending wifi's range in a difficult or large house, including directional antennas and home wiring systems. 2:04:08 PM
MTI MicroFuel powers RFID tags with tiny fuel cell:
Production to begin under contract this summer. "MTI MicroFuel Cells Inc. will supply the power source for a new product to be manufactured by Intermec Technologies Corp. and used in an inventory tracking system." 2:00:40 PM
Tuesday, May 11, 2004
MOTE-KIT 5x4x: XBow has new sensor gear. Kits integrate up to 8 sensors for $2000. Upgrades are annouced to support zigbee. New products:
Friday, May 07, 2004
PMICRO Temperature recorder
: Cheezy wired temperature sensor gear that uses SNMP and ethernet for data collection. Very cheap: $200 per ethernet collection box, wired to up to 16 daisy-chained $15-25 sensors. 4:49:16 PM
Internet-Enabled Wireless Web Sensor Network (WWSN)
: "Combining direct sensor inputs and microprocessor based transmitters employing time division multiple access (TDMA) techniques, this system allows large networks of remote transmitters to communicate digital data to a single receiver. A sleep timer with random wake-up allows multiple periodic transmitters to operate on the same communications channel (418 MHz RF) with a very low collision probability. Each transmitter includes sensor signal conditioning, multiplexer, 16 bit A/D converter, microprocessor, and RF link. The transmitters are compatible with a wide variety of sensors, including thermocouples (cold junction compensated), strain gauges, load cells, torque transducers, and displacement transducers (DVRT’s).
The receiver includes a single board computer (SBC) with Ethernet capability, built in XML and HTML (internet enabled) file transfer protocols, and data storage capability. The web server interrogates the SBC from a standard web browser (MicroSoft’s Internet Explorer or Netscape’s Navigator) to receive multi-channel sensor data from the SBC in extensible mark-up language (XML) format." User manual and pricing online, currently $895 for wifi or ethernet base station, $395 for temperature/humidity node, $2495 for 3 node, base station and software." 4:21:32 PM
How Secure Is Secure?
Simple description of 802.11 and other signal processing, and how more advanced signal processing like direct-sequence spread spectrum (DSSS) can enhance security. In effect, the signal can disappear below the noise level, and only be detected by knowing where to look (which frequencies and time slots) in advance. 4:07:34 PM
Wednesday, May 05, 2004
Expanded footprint:"Thuraya Satellite has announced that it has expanded its satellite telecommunications southward in Africa, thereby providing blanket coverage to Kenya, Uganda, Democratic Republic of the Congo, Gabon, Rwanda, Burundi, Angola, Zambia, Malawi, Mozambique, the Seychelles, Zimbabwe, and Tanzania...
Last October, Thuraya announced its imminent expansion into East and South East Asia by the end of this year, in response to high demand and growth opportunities in these new market segments. The expanded Far East footprint includes Brunei, Cambodia, China, East Timor, Indonesia, Japan, Lao, Malaysia, Mongolia, Myanmar, the Koreas, Papua New Guinea, Philippines, Thailand, Vietnam and Singapore as well as large area of Eastern Russian Federation. " I wonder if rBgan will come with it, or if rBgan will remain only on the original satellite and footprint. 1:42:20 PM
Tuesday, May 04, 2004
Diskless, Low-Form-Factor OpenBSD Systems:
"In a previous article
we built a tiny OpenBSD system out of a Soekris miniature PC, a bootstrap workstation, and a Compact Flash (CF) card. While this combination works nicely for many purposes, once you have Soekrii scattered all around your network, managing the CF cards can be annoying. Replacing the CF cards with a diskless boot system eases management problems. " 5:39:48 PM
Lloyd's satellite constellations
: "These pages form an index to useful web information discussing [Low Earth Orbit or LEO] satellite constellations. You won't gain a complete picture of what any proposed constellation is capable of, or really in-depth technical details, but you will gain an idea of what the developments in this area are, where the industry and technology is headed - and you will pick up background knowledge of satellites along the way. " 3:27:37 PM
Monday, May 03, 2004
Smart Mobs: Phones, Radio, Elections in Ghana
: "Ethan Zuckerman of Geekcorps notes at etcon panel that the last Ghana election "went considerably more smoothly than the last US national election" due to the use of cellphones and radio to report voting fraud: Whenever someone at a polling place reported fraud, the called the radio station, which broadcast it; the police had to check it out, not having the excuse that they didn't receive a report." 2:11:10 PM
: "Pac-Manhattan is a large-scale urban game that utilizes the New York City grid to recreate the 1980's video game sensation Pac-Man. This analog version of Pac-man is being developed in NYU's Interactive Telecommunications graduate program, in order to explore what happens when games are removed from their "little world" of tabletops, televisions and computers and placed in the larger "real world" of street corners, and cities. A player dressed as Pac-man will run around the Washington square park area of Manhattan while attempting to collect all of the virtual "dots" that run the length of the streets. Four players dressed as the ghosts Inky, Blinky, Pinky and Clyde will attempt to catch Pac-man before all of the dots are collected. Using cell-phone contact, Wi-Fi internet connections, and custom software designed by the Pac-Manhattan team, Pac-man and the ghosts will be tracked from a central location and their progress will be broadcast over the internet for viewers from around the world. " 1:44:44 PM
"Inverse Surveillance" -- What We Should Do With All Those Phonecams: Steve Mann's ideas of citizen "sousveillance" predated the cameraphone phenomena by nearly a decade. [He has] reknown as the longtime online cyborg. He started wearing computers and sent his "eyetap" camera images to the Web way back in 1994. His first reference to his activities as a new kind of newsgathering date back to the day in 1995 when he followed a fire truck to a fire and sent the pictures from his head-mounted camera to the Web ..
In 2000, Mann and his students streamed images directly to the Web when violence broke out at a demonstration by the Ontario Coalition Against Poverty. If you think about it, this kind of journalism is a breakthrough in at least one dimension: whenever police abused their power in past political demonstrations, they made a point of breaking or confiscating cameras. Whether you are a violent demonstrator or an abusive police officer, it doesn't do a lot of good to disguise your misbehavior by trashing a camera if it has already sent images to the Whole Wide World. ..
"Surveillance" is French for "watching from above," but Mann's ["sousveillance"] is French for "watching from below." If you think about it, there really is little that citizens can do at this point to prevent others from watching, listening, and tracking us – but we are beginning to get the tools to watch the watchers. Mann notes that surveillance is about authorities watching from on high, but sousveillance is a down-to-earth human's eye view; surveillance cameras are usually automatic devices statically mounted on the ceiling, but sousveillance is human-situated and eye-level; activities are surveilled by authorities but sousveilled by participants; surveillance is secret but sousveillance is public."
Here's a practical application: People For the American Way Election Protection: "Volunteer poll monitors make EP an effective advocate for voters and a powerful deterrent to those who would try to deny voters their rights. Trained by attorneys and armed with cell phones that connect them with a lawyers hotline, EP volunteers distribute the 'Voters Bill of Rights at the polls and identify and solve problems as they happen -- not after Election Day has passed." They say they will use cameras in cell phones when possible. 1:12:15 PM
A Fine Mesh
: "public safety organizations such as police and fire departments have emerged as the primary early market for mesh wireless systems. These organizations need instant, secure mobile data connections, but today they are stuck with multiple incompatible legacy systems that don't even provide the necessary capacity. With homeland security a pressing concern throughout the US, public safety agencies are in a position spend money on emerging technologies that solve difficult problems. Corporate and residential deployments may take longer," 1:03:22 PM
Electoral Smart Mobs in Kenya
: "For the first time, we Kenyans have more or less agreed that this time we have had a fair election with the highest number of voters turning out to vote. One key instrument has been the mobile phone." Uses: Planning, Campaigning, and Results Dissemination.
"We in the ICT field know this is a best practice on how ICTs can help curb rigging, enhance transparency and keep people together. The two cell phone poviders were licensed less than five years ago and cover most of Kenya and have outstripped fixed lines government provider by more than 300% in that short period. Incidentally, no fixed lines were working in all the polling stations I visited further proving the maxim..Africa telecommunications development will be more wireless than fixed. " 12:45:22 PM