Haptic Feedback For The Blind

December 17, 2010 by Chris Nelson 32 Comments

[polymythic] Is helping the blind see with his haptic feedback device called HALO. At the heart of the device is an Arduino Mega 2560 which senses objects with a few ultrasonic range finders and then relays the information back to the user using some vibration motors from old cell phones. The user can feel the distance by the frequency at which the motor pulses. The faster the motors pulse the closer an object is.

This kind of sensing is something that it can be applied to pretty much any sensor allowing the user to feel something that might be otherwise invisible. While haptic feedback is nothing new its good to see continuing work with new sensors and different setups.

The Heinz Automato

December 17, 2010 by Chris Nelson 27 Comments

[Bill Fienup] and [Barry Kudrowitz]’s robots, The Automatos, have been leaving a sticky path of destruction all over the internet. Their sole purpose: to crap ketchup. They accomplish this feat by dumping a CO2 cartridge into a ketchup bottle at the push of a button, leading to some pretty awesome results. While the details are a little sparse it appears that they are using RC cars for the base and a small air gun CO2 cartridge to push the ketchup. The latest version aka the Atuomato 4 appears to be multi-actuated and can shoot more than once for maximum ketchup proliferation. See some videos of it in action after the break.

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Update: 6809 Computing

December 15, 2010 by Chris Nelson 26 Comments

[Matt Sarnoff] is designing his own 8-bit computer from scratch. This means not only designing the hardware but also writing his own kernel and custom libraries. Since we last saw this 8-bit machine hes added both video and sound output which has allowed him to start developing some software for his computer (see it play Conways game of life after the break).

Sticking with the retro theme of his computer he uses a TMS9918 chip to output the video and a YM2149 for audio. The YM2149 was the audio chip used in the Atari ST allowing him to play songs generated for that system with a little bit of hacking to account for the fact that the Atari ST ran at 8MHz where his Motorola 6809 only runs at 2MHz.

Via [Retro Thing]

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Make Your Own Minimalist AVR ISP

December 14, 2010 by Chris Nelson 31 Comments

Giving a programmer is a great way to get people started in microcontrollers so If you want a cheap simple AVR programmer this might just be what you’re looking for. It combines the V-USB firmware, USBtiny software, a few resistors, and some zener diodes. An interesting trick using this programmer is if your trying to program another 8 pin ATtiny you can use some tape to isolate the USB data pins and then piggyback the target ATtiny on the programmer.

Unfortunately in order to flash the ATtiny for your programmer you need a working programmer so it’s somewhat of a catch-22. Make sure your careful when setting the fuse bits because it will use the reset pin making it hard to reprogram without additional programming hardware. AVRs in general are a great way to start using microcontrollers so if your interested give out tutorials a go. You’ll find some tips to get started in addition to information about using an Arduino, or a DAPA cable to flash the firmware to this chip.

Radar Gun Teardown

November 28, 2010 by Chris Nelson 30 Comments

[Jeri Ellsworth] is at it again, this time she takes apart a hot wheels speed gun and in the process she does a good job of explaining how radar can be used to measure speed. She also demonstrates a way to determine if an object is approaching or receding from the radar gun.

The Doppler shift is one way to remotely measure the speed of an object. It works by measuring the change in frequency of a wave after it strikes an object. Rather than measuring the Doppler shift of the returning wave most radar guns use the phase shift. The reason is that the frequency shift of a relativly slow object (60mph), to a relitivly high frequency signal(10GHz) is small (about 0.893Hz), where the phase shift varies based on the distance of the object. This is all just a stepping stone in her quest to build a crude TSA body scanner.

Retro Adapter For Canon SLR

November 20, 2010 by Chris Nelson 19 Comments

[calculon] was able to modify a “dumb” adapter to allow his Canon SLR to use the aperture and focus on a retro lens. With his new flip mounted wide angle lens he was able to achieve some pretty neat macro shots. By cutting away some of the cheaper ring he was able to feed the wire through and glue it onto the the cameras contact points. The wire was then attached to the inputs on the “new” lens. With a new adapter running about $375 not only was this a neat little hack but it was also a money saver. You can see some more of his photos on his flicker

Beginner Concepts: Powering Your Projects

November 20, 2010 by Chris Nelson 44 Comments

Powering your gadgets generally seems like a necessary evil. To help with this [Felipe La Rotta] made a really nice bench power supply using a PC power supply and a LM317 adjustable voltage regulator. PC power supplies are an example of a switched power supply(more on that later). The LM317 is a type of linear voltage regulator that allows for adjusting the output voltage by varying some resistors. Whats the best way to power your circuits? well that depends…

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