Superpositioned

Theodore Gray, co-founder of Wolfram Research, Inc makers of Mathematica, wrote up an amazing article on making your own light bulb. The project is quick and simple, but a little pricey:

• Element: Tungsten
• Time: 30 minutes
• Cost: Roughly $50

Edison’s first mistake was living before tungsten wire was available. Tungsten is way better than carbon as a filament material, and now you can find it in any metal-supply shop… His second mistake, repeated in classroom physics demonstrations to this day, was using a vacuum to get the air out of the bulb…

If you have ever wanted to play pong on a three dimensional display, then this one is for you. There are 1,000 white LEDs in the matrix that can refresh at a rate of 60 fps.

There are videos included, and they also dance to music. I don’t imagine the videos do the display any justice, though.

Afraid the government is trying to track you? Want to disable your old credit cards wireless signal? Need to get that new backpack out of Macy’s without getting caught? You need to disable those RFID tags.

There are several ways to deactivate RFID-Tags. One that might be offered by the industries are RFID-deactivators, which will send the RFID-Tag to sleep. A problem with this method is, that it is not permanent… The RFID-Zapper solves this dilemma… It generates a strong electromagnetic field with a coil, which should be placed as near to the target RFID-Tag as possible. The RFID-Tag then will receive a strong shock of energy comparable with an EMP and some part of it will blow, thus deactivating the chip forever.

If this zapper was bigger, then I could mess up Wal*mart’s inventory for months.

Lately I have been daydreaming a lot in my laser communication course. Surfing around Google after class, I managed to find an article on sending serial port data over a laser link. The article is rather old (1997), but was published in a prominent Australian magazine. This is way back when a good, red laser pointer was only $70.

All said, this is an interesting read. It would be nice to see this applied to more practical situations. Many computers do not even have serial ports anymore. We have been discussing the feasibility of using a laser to send video signals in the DIY Live Forums. The idea is great because running cable your projector is often a major problem in home theaters. Unfortunately, I have no home theater and my only only monitor is an old, huge CRT. I will have to find another excuse to play with lasers.

On a side note, it is theoretically possible to send terabits of data per second over one channel, because the optical frequency of a laser is extremely high (~460 terahertz for a red laser). This bandwidth is limited to mere gigabits by the response time of current optical detectors and circuitry, though.

I recently discovered an interesting application note from National Semiconductor in October of 1999. The article details nine sine wave generation techniques. Some techniques can be accomplished several ways so there are more than nine circuits available. The note also tabulates each technique with its frequency range, typical distortion, and amplitude stability. Both fixed frequency and adjustable frequency oscillators are covered. The simple crystal oscillator also has one of lowest distortion rates.

A recent post regarding high altitude balloons in the DIY Live Electronics Forums reminded me of an older altimeter project I wanted to copy for my model rockets. His original design uses a Basic Stamp to record pressure data from a sensor. Due to price constraints and chip loss, he changed to the cheaper PIC microcontroller. Later designs implemented a accelerometer and temperature recording as well.

The site contains schematics and source code, making it an excellent starting point. There is also an Excel spreadsheet to linearize the pressure output and converting it to altitude.

Too bad I lost my interest in model rocketry when I moved into ‘the city.’ Small rockets in the park are not as fun as all the space we had on Daddy’s farm.

The Do It Yourself Laser Light Show has more to do with optics than electronics. Taping a mirror to your sub-woofer and pointing a laser at it is fairly ingenious. At least I never considered it, and I am nuts about lasers.

Most coverage of this project is useless. However, Kenwardtown does an amazing job explaining the mod with detailed pictures. “I recommend you don’t tape anything to the cone itself, because you can damage the cone.”

Valentine’s Day is almost here, so you better have a plan. The LED Flashing Sweetheart Kit may not be a surefire winner, but nothing says love like the labor of your own two hands.

Something like this would not be too hard to pull off on your own. If you go ahead and try it, do yourself a favor and get some dinner reservations. You can always cancel if the gift goes over well.

The hard drive clock is quite possibly the best diy electronics paperweight I have come across. Even though it has no particular use, it is uber cool. The clock requires a PIC 16f628 microcontroller, and old hard disk, and some miscellaneous components.

Unfortunately, the design lacks a real time clock. After a few days, you’re going to be late. He also mentions adding a fancier hourly chime. Personally, I think an old school computer beep and some circling LEDs would be perfect.

Hopefully I can find some time to convert my old 800MB drive into a $300 clock. It would be perfect for my office because the bedroom is definitely out of consideration.

DIYLive.net dug up a simple fm radio. ‘A good starter DIY project for anyone interested in audio.’

AM radio circuits and kits abound. Some work quite well. But, look around and you will find virtually no FM radio kits. Certainly, there are no simple FM radio kits… I have developed this simple radio kit. It is a remarkable circuit. It is sensitive, selective, and has enough audio drive for an earphone.