TALON---the military robot

TALON Robots: Speed, Simplicity, Standoff




TALON robots are powerful, durable, lightweight tracked vehicles that are widely used for explosive ordnance disposal (EOD), reconnaissance, communications, hazmat, security, defense and rescue. They have all-weather, day/night and amphibious capabilities and can navigate virtually any terrain.


How are they different from other robots on the market?

1. Man-portable -- At less than 100 lb (45 kg), TALON can be easily transported and is instantly ready for operation.

2. Rugged -- TALON robots can take a punch and stay in the fight. One was blown off the roof of a Humvee in Iraq recently while the Humvee was crossing a bridge over a river. TALON flew off the bridge and plunged into the river below. Soldiers later used its operator control unit to drive the robot back out of the river and up onto the bank so they could retrieve it.

3. Fast -- TALON is the fastest robot on the market today with seven speed settings.

4. High payload capacity -- Long-term system versatility optimizes investment. TALON has the highest payload capacity and payload-to-weight ratio, allowing for the incorporation of a broad array of sensor packages.

5. Mobile -- Climbs stairs, negotiates rock piles, overcomes concertina wire, plows through snow and surf.

6.Intuitive -- Easiest robot to operate; joystick controls.
Withstand repeated decontamination -- Demonstrated at Ground Zero after 2001 World Trade Center attack in New York City. Electronics withstood 45 straight days of being decontaminated twice a day without failing.

7.Long battery life -- TALON robots have the longest battery life of all man-portable robots.

BUMPER SWITCH
SONAR
CDS CELLS
IR SENSORS
ROBOT SENSORS

BUMPER Switches :

Switchs are probably the simplest sensor to use on a robot. They can detect collisions, limit travel, even detect dropoffs. Their use is almost a requirement to backup other sensors that may fail. Putting them together just involves bolting them down and providing enough of a lever to actuate them easily. Builders have added length to the lever already there or even placed a balanced ring around several for a circular bumper around the robot. Drop detectors would have feelers beneath the robot sliding across the floor. Very simple operation which allows for reliable detection, what every robot needs.

CdS Cells :

Another simple sensor for robots uses the light sensitivity of Cadium Sulfide or CdS cells. These change resistance based on the intensity of light shining on them. In the dark, they can be in the 100s or more of kohms. In light, they can be less than 1k. Their use would be in a resistive divider between 5 volts and ground, either as the top or bottom with the output between the CdS cell and the current limiting resistor. This would provide a highly variable analog signal to a controller, which could cause irregular switching. If the controller supports it, an analog input could be used to read these, or if not, an analog to digital converter (ADC) or a comparator could make the input more usable. These work well for finding light and dark areas or in line detection in line following robots.

Infra Red Sensors :
InfraRed sensor circuits have many varieties. The simplest uses an IR LED to deliver the light and an IR sensitive phototransistor to see it. The phototransistor turns on when IR light hits it, whether from the LED or ambient sources or reflected. The circuit shown should deliver an output if any IR light shines on it. Typical values for the resistor going to the phototransistor collector would be around 10K ohms or so. LEDs are usually driven through 200 to 1K ohm resistors. When no IR light is can be seen by the detector, you should see a good high (5 volt) from the output connected to the collector. When IR light is present, the phototransistor should conduct and you should see a good low, probably around 0.7 volts. One simple use might involve line detection, with sensors on either side and on a line to be followed by the robot.
More sophisticated IR usage involves pulsing IR light at a known frequency, and using a detector that is attuned to that frequency. The circuitry within the Sharp GP1U58Y series tunes the detector to a specific frequency. Each is sensitive to IR that has been pulsed at that given frequency in short bursts. This encoding of the IR helps to mask out external sources that might have been in the way of information we really want, specifically how close something is or the recieving of coded data. What is needed for proximity detection is an IR source that outputs light at the specified frequency and on time for that freqency to match the detectors reception charecteristics. Various circuits work, from 555 timers that drive the IR LEDs to simply hooking them to lines from your controller and programming in the appropriate driving sequence. My use has been with Dennis Clarks IR proximity detector, based on the DPRG IR proximity detector by Jeff Koenig. This circuit uses a PIC to generate the appropriate frequency and pulsing for left and right IRs, counts the number of detections for each side and finally outputs a good dectection for either the left or right side. Doing this all on a seperate processor frees up the controller for other tasks in driving a robot. It can use the Sharp detector, a Radio Shack LiteOn detector, or a Panasonic PNA4601M series. I've used both the Sharp and the Panasonic PNA4602M. The board provides excellent right and left detections, and is only confused in rooms with high flourescent lighting. In these I plan to try the little trick of using a small strip of exposed film or perhaps some of the red plastic for remotes in front of the detector to hopefully shield some of the flourescent "noise" that overloads it.

More advanced infrared sensors come in "all in one" packages, such as the Sharps GP2Dxx series. These sensors can provide range information, in either analog or digital form, or simply be a trigger point when something is within an adjustable range. The GP2D02 gives an 8 bit digital reading when triggered. GP2D05s give an high or low signal when a specific preset range is reached. GP2D12s output an analog voltage corresponding to range continuously. GP2D15s output a high or low when crossing a 9.5" distance. All typically have detection capabilities from 4" to 31" and cost anywhere from $13 to $25, depending on capabilities.
IRLED phototransistor pairs can be used for encoders. Either a reflective pair which can count strips on a wheel or a slotted type to count slits in a wheel are possible. Several different types exist, usually in the form of quadrature encoders. Quadrature encoders use 2 pairs of sensors which are placed out of sequence with each other to allow knowing the direction a motor is turning, as well as how far or fast it is going. Some people have even hacked these from inside computer mice. One further advanced use of IR is in it's basic use in remote control. Again appropriate sequencing is needed, but information can be transmitted and received, just as you turn on and off your TV. Dennis Clark has again put this to use in an encoder/decoder pair of PICs for transmitting and receiving information. Other web pages discuss the coding sequences on regular TV remotes and provide some information as to the sequences involved. I haven't used this yet, but can see it as a great way to start your robot remotely or drive it or possibly have a data link between the robot and a computer.
Sonar :

Sonar provides another method of telling your robot where things are. The Polaroid Sonar rangers have been good at providing the distance to an object through pinging a transducer and waiting for a return echo. Your controller times the period between the initial pulse and the return echo. And through a quick calculation you've got the distance to whatever the sound bounced from, based on sound traveling about 1 inch in 74 microseconds. The Polaroid modules can range from about 6 inches to 35 feet. Some folks have used modules taken from cameras and hacked for providing a signal. This allows a cheaper solution than buying a full Polaroid development kit for $40 to $70. Some sonar cameras can be had for as little as $5 through thrift stores and only require a few additional cheap parts to work. One new alternative is the sonar module put together by Devantech. The Devantech modules range is about 1 inch to 10 feet and the price is about $25. The interface is relatively simple for most controllers.

CAPACITOR

CAPACITOR:




In a way, a capacitor is a little like a battery. Although they work in completely different ways, capacitors and batteries both store electrical energy.


A battery has two terminals. Inside the battery, chemical reactions produce electrons on one terminal and absorb electrons at the other terminal.


A capacitor is a much simpler device, and it cannot produce new electrons -- it only stores them.



Like a battery, a capacitor has two terminals. Inside the capacitor, the terminals connect to two metal plates separated by a dielectric. The dielectric can be air, paper, plastic or anything else that does not conduct electricity and keeps the plates from touching each other. You can easily make a capacitor from two pieces of aluminum foil and a piece of paper. It won't be a particularly good capacitor in terms of its storage capacity, but it will work.


When you connect a capacitor to a battery, here’s what happens:
The plate on the capacitor that attaches to the negative terminal of the battery accepts electrons that the battery is producing.
The plate on the capacitor that attaches to the positive terminal of the battery loses electrons to the battery.


Once it's charged, the capacitor has the same voltage as the battery (1.5 volts on the battery means 1.5 volts on the capacitor). For a small capacitor, the capacity is small. But large capacitors can hold quite a bit of charge. You can find capacitors as big as soda cans, for example, that hold enough charge to light a flashlight bulb for a minute or more. When you see lightning in the sky, what you are seeing is a huge capacitor where one plate is the cloud and the other plate is the ground, and the lightning is the charge releasing between these two "plates." Obviously, in a capacitor that large, you can hold a huge amount of charge!


Here you have a battery, a light bulb and a capacitor. If the capacitor is pretty big, what you would notice is that, when you connected the battery, the light bulb would light up as current flows from the battery to the capacitor to charge it up. The bulb would get progressively dimmer and finally go out once the capacitor reached its capacity. Then you could remove the battery and replace it with a wire. Current would flow from one plate of the capacitor to the other. The light bulb would light and then get dimmer and dimmer, finally going out once the capacitor had completely discharged (the same number of electrons on both plates).


The difference between a capacitor and a battery is that a capacitor can dump its entire charge in a tiny fraction of a second, where a battery would take minutes to completely discharge itself. That's why the electronic flash on a camera uses a capacitor -- the battery charges up the flash's capacitor over several seconds, and then the capacitor dumps the full charge into the flash tube almost instantly. This can make a large, charged capacitor extremely dangerous -- flash units and TVs have warnings about opening them up for this reason. They contain big capacitors that can, potentially, kill you with the charge they contain.


FARADS:




the unit of capacitance is a farad. A 1-farad capacitor can store one coulomb (coo-lomb) of charge at 1 volt. A coulomb is 6.25e18 (6.25 * 10^18, or 6.25 billion billion) electrons. One amp represents a rate of electron flow of 1 coulomb of electrons per second, so a 1-farad capacitor can hold 1 amp-second of electrons at 1 volt.


A 1-farad capacitor would typically be pretty big. It might be as big as a can of tuna or a 1-liter soda bottle, depending on the voltage it can handle. So you typically see capacitors measured in microfarads (millionths of a farad).






To get some perspective on how big a farad is, think about this:




A typical alkaline AA battery holds about 2.8 amp-hours.


That means that a AA battery can produce 2.8 amps for an hour at 1.5 volts (about 4.2 watt-hours -- a AA battery can light a 4-watt bulb for a little more than an hour).


Let's call it 1 volt to make the math easier. To store one AA battery's energy in a capacitor, you would need 3,600 * 2.8 = 10,080 farads to hold it, because an amp-hour is 3,600 amp-seconds.


If it takes something the size of a can of tuna to hold a farad, then 10,080 farads is going to take up a LOT more space than a single AA battery! Obviously, it is impractical to use capacitors to store any significant amount of power unless you do it at a high voltage.
Capacitors are used in several different ways in electronic circuits:


Sometimes, capacitors are used to store charge for high-speed use. That's what a flash does. Big lasers use this technique as well to get very bright, instantaneous flashes.


Capacitors can also eliminate ripples. If a line carrying DC voltage has ripples or spikes in it, a big capacitor can even out the voltage by absorbing the peaks and filling in the valleys.

LIGHT PENS

Hey guys, after a lot of theory lets hop on to some technical advancements...
U can see a light pen in the above pic. wanna know about light pen????
given below are the details of this pen!!!
Light Pen, a pointing device in which the user holds a wand, which is attached to the computer, up to the screen and selects items or chooses commands on the screen either by pressing a clip on the side of the light pen or by pressing the light pen against the surface of the screen.


The wand contains light sensors and sends a signal to the computer whenever it records a light, as during close contact with the screen when the non-black pixels beneath the wand's tip are refreshed by the display's electron beam.


The computer's screen is not all lit at once—the electron beam that lights pixels on the screen traces across the screen row by row, all in the space of 1/50 of a second.its hard to imagine.. right???


By noting exactly when the light pen detected the electron beam passing its tip, the computer can determine the light pen's location on the screen.


The light pen doesn't require a special screen or screen coating, as does a touch screen, but its disadvantage is that holding the pen up for an extended length of time is tiring to the user.


Light pens are often used in computer-aided design and computer-aided manufacture (CAD and CAM) technology because of the flexibility they provide.

what a wonderful invention.. isn't it??????

SOLID PROPELLENT ROCKETS

INTRODUCTION
ROCKET, general term for a jet propulsion device propelled by the expulsion of gases generated in a combustion chamber. Since the combustible propellants contain both fuel and an oxidizer, a rocket develops thrust independent of its surroundings, unlike other types of jet engines that utilize oxygen from the atmosphere to burn fuel carried aboard. A rocket engine, therefore, is self-contained and is the only type of device suitable for flight propulsion into outer space.

Thrust to propel a rocket is based on Isaac Newton's third law of motion (see Mechanics), which states that for every action, there is an equal and opposite reaction.
The amount of thrust developed by a rocket motor depends mainly on two factors, the velocity with which the burning gases leave the combustion chamber, and the mass of the burning gases.

The term rocket has frequently been used to describe both the thrust-producing device and the whole rocket-powered vehicle. To avoid confusion, especially in the case of large vehicles such as missiles and space-launch vehicles, we also call the propulsion device as a rocket engine.


SOLID PROPELLENT ROCKET:

Early solid-propellant rockets were powered by the combustion of a mixture containing the same ingredients as black gunpowder, but in different proportions.
Gunpowder - 75 % saltpetre,
12 % sulphur,
13 % charcoal by weight.
Rocket charges consisted of - 60 % saltpetre,
15 % sulphur,
25 % charcoal.
Because of this different composition, the rocket charge burned more slowly than gunpowder.

The principal parts of the solid-propellant rocket are
(i) payload(consisting of the warhead or scientific instruments)
(ii) combustion chamber, or motor( containing the fuel charge and nozzles to expel the combustion gases) Fins may be added to stabilize its flight.

Solid-propellant rockets today are divided into two categories,
(i)those with unrestricted burning charges
(ii) with restricted burning charges, known also as wall-fitting charges.

An unrestricted burning charge also may be shaped in the form of a thick-walled hollow tube, which burns at both its inside and outside surfaces. No matter what its size or shape, the charge is called a grain and the devices that hold it in place are known as traps. Unrestricted burning charges have burning times of less than one sec.

For longer burning times a wall-fitting charge is used. This type of charge either burns across its cross section, or it may be hollowed out at the centre so that it burns from the inside towards the rocket wall. The latter method permits a reduction in the thickness of the wall of the outer metal tube of the rocket, because for virtually all of the burning time, the metal tube is reinforced by what is left of the charge.

Modern solid-propellant charges are of very large size. For example, the take-off weight of the solid-propellant submarine-launched Trident-II D5 missile is about 59,000 kg . The two solid rocket boosters (SRBs) on the space shuttle weigh more than half a million kg each. Made of 11 steel segments, the SRB is the largest solid-propellant rocket ever built in the United States. As a result of the Challenger space shuttle disaster, the seals between the segments were redesigned to prevent a recurrence of the problem that caused the destruction of the spacecraft.

spidey's web

 case you haven’t heard, there’s a new “Spider-Man” movie out. And once we get past all the trailers, posters and publicity shots, the question on everyone’s mind is whether it lives up to the previous films. For the most part, it does. It’s not as good as “Spider-Man 2,” but then again, that movie was such a great superhero film, it’s hard to beat.

“Spider-Man 3” is on par with the first “Spider-Man,” and that is refreshing. After all, “Spider-Man” helped set the standard for modern superhero movies, and it proved that “X-Men” wasn’t a fluke. Considering that the third movie in a series is often a dud (e.g., “Superman III,” “Batman Forever” and “Leprechaun 3”), it’s great to see the series at least keeping up with itself.

This new movie takes off with Peter Parker (Tobey Maguire) and Mary Jane Watson (Kirsten Dunst) in love. However, they are having some problems dealing with each other’s fame. Harry Osbourne (James Franco) has resurrected the Green Goblin’s persona as the New Goblin, seeking revenge on Spider-Man.

Meanwhile, the police have found the real killer of Uncle Ben, a two-bit crook named Flint Marko (Thomas Haden Church). He’s escaped and, due to a freak of science accident, he has been transformed into the Sandman. At the same time, a mysterious black substance from outer space is infecting the Spider-Man suit, making Peter and his alter ego overly aggressive.

There’s a lot of story here, probably enough for two movies, and this seems to be the focus of much of the film’s criticism. I’ll admit that “Spider-Man 3” isn’t perfect, but these early reviews seem a little harsh. While the complaints are not unfounded, the movie’s sins are mostly forgivable (except for this strange little jazz club scene in the middle of the film – you’ll know what I’m talking about when you see it).

The biggest sticking point is the film’s running time, two hours and twenty minutes. The first two films clocked in at just about two hours each, so “Spider-Man 3” is noticeably longer. However, I would prefer a longer running time to deal with the large cast of characters than to rush the story.

Yes, the script is crowded, but I would hardly say it was convoluted. In fact, I was pretty impressed with how the script managed to juggle so many characters at once and actually make them relevant. “Batman Forever” and “Batman and Robin” this is not. While there are a lot of characters, and maybe too many villains, they all manage to have an important role to the story.

The weak link in the story is Kirsten Dunst. Her character has never been my favorites – a bit of a whiney prima donna if you ask me – and the movie focuses too much on her relationship with Peter. It seems we’ve been down that road already in the past two films. In this sequel, it was nice to see a potential new love interest for Peter with Gwen Stacy, played by an unbelievably hot Bryce Dallas Howard.

And yes, the dialogue is a bit hacky, but that’s nothing new. The “Star Wars” prequels had some of the corniest lines in them, but I still consider them to be fantastic movies. (Well, at least “Attack of the Clones” and “Revenge of the Sith” were.) Actually, the somewhat campy script is a bit nostalgic in a way. It reminded me of the rough dialogue given to the web slinger by Stan Lee in the 1960s comic books.

But enough about the movie’s rough spots. There’s a lot to love about this new “Spider-Man.” The biggest win comes from the effects and the action sequences. These are brilliant and thrilling, some of the best you’re gonna see. Even if you don’t like the story, the movie is book-ended with two of the greatest action sequences you’ll see this year.

“Spider-Man 3” is getting a bad rap from some, but that’s because the bar has been set so high from the previous films and superhero films in general today. If a film like “Spider-Man 3” came out ten years ago, it would he heralded as one of the greatest superhero films of all time. Now, compared to the others, it’s not as impressive, but still at the top of a relatively short list.



critics cinematometer...........65%


rating...........3.5/5

aata......a.k.a gu gu gudamba shankar

Story

Sri Krishna (Siddhardh) grows up watching films playing in the theater in which his father works as a movie-projectionist in a village. Satya (Ileana) is harassed by Vicky (Munna) - son of a politician - who wants to marry her. Satya escapes from home and Sri Krishna falls in love with her the first time he meets her. As the goons and police chase Satya, Sri Krishna protects her and drops her in the house of the politician. He wins Munna’s confidence. The rest of the story is the one-sided game between Sri Krishna and Munna.

Artists Performance

Siddhardh: Siddhardh has always played the character of an NRI or a boy from upper class in all Telugu films (Boys, Yuva, NVNV, Chukkallo Chandrudu and Bommarillu). For the first time, he has donned a character from lower middle class family. His role is that of a movie buff who loves Telugu films and old classics. Hence it is extremely important to have an actor that pronounces the dialogues the same way heroes does in old films. Siddhardh tried his best, but could not get the best dialogue delivery to suit the requirements. He altered his hair style and performed effortlessly in all the scenes.

Ileana: Ileana is gorgeous as female lead in this film. She is beautifully showcased in the songs. She is awesome in 4th and 5th song of the film. This is probably the 3rd film after Devadas and Pokiri where she is a treat to the eyes. She also gave some unique expressions in the boat episode. It has become a fad to keep a dialogue reserved for her behind in the recent films of Ileana.

Others: New actor Vicky is alright as Munna. In the comedy department, Jaya Prakash Reddy is pretty good with his dialect. Sunil and Brahmanandam have done characters that are similar to what they have been doing in previous films. They generated good amount of comedy. Ravi Babu character is good. Yesteryear's vamp Anuradha played Jaya Prakash's wife. Singer Smita performed in a song. Sayaji Shinde did the role of a cop. Producer MS Raju gave guest appearance in a song.

Technical Departments:

Story: The story and scenes of the film draws huge inspiration from several films. The basic plot is very similar to that of Gudumba Shankar. The first half is all about the couple on run. The second half is all about how hero makes fun of the villain who is all set to marry heroine. The other inspirations include Cinema Paradiso (opening sequence), Project A (first fight), Dil Hain Ki Maanta Nahin (hero - heroine meeting for the first time) and Mr. Bean (Sunil running nude in a hotel).

Screenplay - direction: Since there is hardly any story in the film, it is pretty difficult to write screenplay. Screenplay of the film is ok except for the climax. The director tried to create a sensible link to the incidents happened with the climax, but it hardly works. The director banked more on comedy and songs to narrate the story. He also concentrated less on establishing the love between the lead pair. The emotions are not strongly established.

Other departments: The cinematography takes the top slot in technical departments. Chota K Naidu made sure that he exploited good locations in the first half. Music by Devi Sri Prasad is alright. The picturization of songs is good. Dialogues by Paruchuri have sparks at times. Artwork by Ashok is very good. Production values by Sumanth Art banner are grand.

Analysis: MS Raju is always known for putting a strong emotional content in all his films irrespective of their box office performance. For the first time, he attempted making a film that does not have any emotional depth. He tried to do a breezy film this time. The plus points are entertainment and songs. The negative points are lack of emotions and unimpressive climax. We have to wait and see how common audience receive this film.


critics cinematometer.......................57%

rating -------2.5/5