Retrotechtacular: Radar Jamming

It’s been said that the best defense is a good offense. When aloft and en route to deliver a harmful payload to the enemy, the best defense is to plan your approach and your exit carefully, and to interfere with their methods of detection. If they can’t find you, they can’t shoot you.

As of May 1962, the United States military was using three major classifications of radar jamming technology as described in this week’s film: the AN/ALQ-35 multiple target repeater, the AN/ALQ-55 communications link disrupter, and the AN/ALQ-41 and -51 track breakers. The most important role of these pieces of equipment is to buy time, a precious resource in all kinds of warfare.

The AN/ALQ-35 target repeater consists of a tuner, pulse generator, transmitter, and control panel working in concert to display multiple false positives on the enemy’s PPI scopes. The unit receives the incoming enemy pulse, amplifies it greatly, repeats it, and sends them back with random delays.

The AN/ALQ-55 comm disrupter operates in the 100-210MHz band. It distinguishes the threatening enemy communication bands from those of beacons and civilians, evaluates them, and jams them with a signal that’s non-continuous, which helps avoid detection.

Finally, the AN/ALQ-41 and -51 track breakers are designed to break enemy lock-on and to give false information. It provides simultaneous protection against pulse ranging, FM-CW, conical, and monopulse radar in different ways, based on each method’s angle and range.

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Jamming Robot will Destroy You at Beer Pong

DSC_0363Wandering the aisles of Eureka Park, the startup area of the Consumer Electronics Show, I spotted a mob of people and sauntered over to see what the excitement was all about. Peeking over this gentleman’s shoulder I realized he was getting spanked at Beer Pong… by a robot!

Those in the know will recognize that the bot has only 3 cups left and so the guy definitely was giving it run for its money. But the bot’s ability to swish the ball on nearly every throw accounts for the scoreboard which read Robot: 116, Humans: 11. Unlike the ping pong robot hoax from last March, we can vouch for this one being real!

If you’re trying to attract the geek demographic, this must be one of the best offerings ever shown at a trade show. Empire Robotics manufactures the VERSABALL gripper. We know this as a jamming gripper and have been looking at the tech progress for many years now. Looking back to this Cornell research video from 2010 we realize it is based on the white paper which [John Amend, PhD] co-authored. He’s now CTO and Co-Founder of the company and was one of the people running the booth. We love it when trade show booths are staffed by the engineers!

Join me after the break for a rundown of how the system works along with a video clip of it hitting the target.

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Dead simple jamming gripper design


This jamming gripper design is the simplest we’ve seen so far. It uses a syringe to generate the suction necessary for the orange appendage to grip an object.

As with previous offerings this uses coffee grounds inside of a balloon. When pressed against an object the grounds flow around it. When a vacuum is applied to the balloon those grounds are locked in place, jamming themselves around the item for a firm grip. About a year ago we saw a hardware-store grade design which used a vacuum pump for suction and a shower head as the gripper body. This time around the plastic syringe serves as both.

The plastic tip was cut away and the resulting hole covered with a cloth to keep the coffee in place. After installing the coffee-filled balloon the grip can be operated by pulling the plunger to lock the grounds in place. It’s not going to be as easy to automate as a pump-based rig. But if you just want to toy with the concept this is the way to go.

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Jamming gripper that’s super easy to build

This is the simplest version of a jamming gripper that we’ve seen yet. The only component that might not be readily available is the pump in the upper left, but the rest is all hardware or grocery store stuff. It’s based on the concept we saw from a research video where the air in a bladder full of coffee grounds is removed to grip an item. In this case the bladder is a party balloon which is held in place by parts from a cheap shower head. A theaded-to-barbed right angle connector makes it easy to connect the vinyl tubing up to the pump.

The video after the break shows that this works quite well for small items. But we see a lot of downward force is exerted to firmly embed them in the grounds. We’re not sure if this is par for the course, or if it would work a bit better if more air were in the bladder initially. This other jamming gripper build uses a servo to release pressure from the system, and we think that might be of help here too.

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WiFi jamming via deauthentication packets

[Elliot] put together an intriguing proof-of-concept script that uses repeated deauthentication packet bursts to jam WiFi access points. From what we can tell it’s a new way to use an old tool. Aircrack-ng is a package often seen in WiFi hacking. It includes a deauthentication command which causes WiFi clients to stop using an access point and attempt to reauthenticate themselves. [Elliot’s] attack involves sending repeated deauthenitcation packets which in essence never allows a client to pass any data because they will always be tied up with authentication.

After the break you can see a video demonstration of how this works. The script detects access points in the area. The attacker selects which ones to jam and the script then calls the Aircrack-ng command. If you’ve got an idea on how to protect against this type of thing, we’d love to hear about. Leave your thoughts in the comments.

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Jamming gripper completes robot drug dealer

Here’s an inexpensive way to build your own jamming gripper. [Steve Norris] combined a robot arm with a few inexpensive items to achieve similar results as the original. Much like the last DIY version he started with a balloon and some coffee grounds, but instead of using his own body as a vacuum pump he sourced a Reynolds Handi-Vac, an inexpensive food vacuum sealer. It connects to the balloon using some plastic tubing, and sucks all of the air out, locking the coffee grounds around an object for a firm grip. The video after the break even shows the gripper picking up two aspirin. At first we thought a servo motor was being used to seal off the tube once the air had been pumped out. Instead, it is covering a hole in the tubing, which breaks the vacuum when it’s time to let go of an object.

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Robot gripper uses coffee to pick up anything

Picking up a raw egg is not something we’d think a robot gripper would be good at. But this model uses a bulbous tip instead of claw, which makes crushing the object less of a concern.

That tip is kind of like a balloon. It is stretched full with coffee grounds but air can also be pumped in and sucked out. When it comes time to grip an object, a bit of air is pumped in and the bulb is pressed down on its target. Once in place all of the air is sucked out, locking the coffee grounds around the object. Take a look after the break to see just how many things can be gripped with this technique.

Now the real question, can it bring me a beer?

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