Gesture Based Security Lock

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A team of students from Cornell University are looking into alternative ways of creating a security system that can be locked or unlocked by using physical gestures in an enclosed space.

It is the final year project for [Ankur], [Darshan] and [Saisrinivasan] in their MEng of Electrical and Computer Engineering. The system prototype is capable of recording a gesture and then comparing the gesture with future gestures to lock or unlock the system. Consider it like a secret handshake to get into the office!

To analyze the gesture they are using four SparkFun proximity sensors setup in a linear array to sense the distance a hand is moved. An ATMega1284P is used to convert the analog sensor signal to digital for further processing. The project is extremely well documented, as it appears to be the final report for the project.

A short video after the break shows off the prototype and gives a good explanation of how the system works.

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Pair of musical hacks use sensor arrays as keyboards

sensor-driven-musical-keyboards

This pair of musical keyboard hacks both use light to detect inputs. The pair of tips came in on the same day, which sparks talk of consipiracy theory here at Hackaday. Something in the weather must influence what types of projects people take on because we frequently see trends like this one. Video of both projects is embedded after the jump.

On the left is a light-sensitive keyboard which [Kaziem] is showing off. In this image he’s rolling a marble around on the surface. As it passes over the Cadmium Sulfide sensors (which are arranged in the pattern of white and black keys from a piano keyboard) the instrument plays pitches based on the changing light levels. [Thanks Michael via Make]

To the right is [Lex's] proximity sensor keyboard. It uses a half-dozen Infrared proximity sensor which pick up reflected light. He calls it a ‘quantised theremin’ and after seeing it in action we understand why. The overclocked Raspberry Pi playing the tones reacts differently based on distance from the keyboard itself, and hand alignment with the different sensors.

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Simple proximity sensor

[Dustin Andrews] built this add-on board which works as a proximity sensor. He wanted a standalone sensor for his Arduino projects which would use a single pin as a trigger. This lets him alert the Arduino when an object approaches the sensor without the need for polling or extra code on the Arduino side of things.

As you can see, a single chip on the board takes care of all the work. That’s an ATtiny13, they’re inexpensive and sometimes you can even salvage them from consumer electronics like this color changing light bulb. The microcontroller monitors the phototransistor which is wrapped in electrical tape to isolate it from the IR LED emitters on either side. This setup creates a reflective sensor. When an object nears the board, the infrared light from the emitters reflects off of it and onto the phototransistor. And since the Arduino works as an AVR programmer you don’t need special hardware to program the device.

Build your own miniature self parking car

self-park

[Achu Wilson] was watching TV when he saw an ad for Volkswagen’s latest Passat, which happens to come equipped with a park assist mode. This essentially allows the car to park itself with little to no user interaction. While these systems come as a pricey add-on option, he figured he could build something similar in his own home, albeit on a much smaller scale.

Digging through his parts bin he only came across a single infrared proximity sensor, so instead of building vehicle that could parallel park, he settled on constructing one that can situate itself in a traditional parking spot instead. The car is built from wood and a pair of DC motors [Achu] had on hand, both of which are controlled using an ATmega16.

As a proof of concept, it looks to work pretty well despite the fact that it only has a single fixed sensor navigate its surroundings. We imagine it would be a relatively easy task to adapt the system for parallel parking, among other things.

Continue reading to see [Achu's] self-parking car in action.

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Medusa: a proximity-aware tabletop

Finally [Michelle Annett] can talk about her super secret project she did at Autodesk Research.

Medusa, as [Michelle]‘s project is called, is a Microsoft Surface that has been fitted with 138 proximity sensors. This allows the Surface to sense users walking up to it, and detect users hands and arms above the table top. Multiple users can be detected at the same time, and the left and right hands of two users can be mapped to specific users.

The proximity sensors [Michelle] used are inexpensive, so we’re wondering when someone with a crazy multitouch setup will add proximity sensors to their build. We’d like to play with Medusa, even if just for a virtual game of Settlers of Catan. It seems like the perfect setup…

[Michelle] built Medusa last January during her internship at Autodesk. Now that UIST 2011 is over, she can finally talk about it. There’s also a video demonstrating the possibilities of Medusa, check it out after the break.

Thanks [Fraser] for sending this one in.

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Nimbus, the wall-following robot

nimbus_wall_following_robot

[Johannes] sent in the latest iteration of an ongoing project – Nimbus, the wall-follwing robot. Originally operating on a cardboard frame, the robot has undergone several revisions as you can see by reading through his blog. Nimbus started out as a simple, Arduino-powered robot, but the project has progressed nicely over time. The last revision simply avoided walls, using a Sharp IR proximity sensor to detect, then avoid obstacles. The most recent model sports a nice polycarbonate frame as well as two additional IR proximity sensors, allowing Nimbus to navigate quite well, following walls and avoiding obstacles with ease. It does get caught up from time to time on carpets and wires, but overall Nimbus is a great little robot. [Johannes] even added a small RGB status LED for the bottom of the bot, communicating its navigation status to the operator at all times. This is done by flashing various colors when objects have been discovered or have moved out of sight – it’s a really novel addition.

Keep reading for a video of Nimbus navigating his way around, and don’t forget to check out the Nimbus photo stream.

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Parts: Digital proximity sensor (Sharp GP2Y0D02)

The GP2Y0D02 is an infrared proximity sensor with a detection field that extends 80cm. This type of sensor can be used to build collision avoidance systems for robots. We’ll demonstrate this sensor using a single resistor and a multimeter.

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