Archive for the ‘Informative’ Category
From ni.com:
National Instruments today announced that Dr. Michio Kaku best-selling author and professor at City College of New York, will deliver the closing keynote address at NIWeek 2010, the world’s largest graphical system design conference and exhibition scheduled for Aug 3–5 in Austin, Texas“We are excited to welcome Dr. Michio Kaku to NIWeek as this year’s guest keynote speaker,” said Ray Almgren, vice president of software and education at National Instruments. “Dr. Kaku’s expert insight on future technologies is especially beneficial to the thousands of NIWeek attendees who are continually innovating and pushing the boundaries of science and engineering.” In addition to his Henry Semat Professorship in theoretical physics at City College of New York, Dr Kaku is an author of several best-sellers, including“Hyperspace,” “Visions” and “Physics of the Impossible,” and host of the national radio program,“Explorations in Science.” He also has hosted numerous documentaries for the Discovery Channel Science Channel and the BBC about the future of science. Additionally, his doctorate-level textbooks are required readings at some of the world’s leading physics laboratories. Prior to his current position, Dr Kaku held a lectureship at Harvard University and a visiting professor position at the Institute for Advanced Study at Princeton. Dr. Kaku received a Bachelor of Science degree from Harvard University and a doctorate in theoretical physics from Berkeley Radiation Laboratory at the University of California Berkeley Dr. Kaku co-founded string field theory, a branch of string theory that summarizes the five string theories into one equation. Dr. Kaku also continues to search for Einstein’s “theory of everything” that unifies the four fundamental forces of the universe. In addition Dr. Kaku has interviewed more than 300 scientists to decipher the most accurate prediction of what the next 20 years of science holds.
From the New York Times, Tesla predicting cell phones:
This has been an interest of mine for a while and I have researched and developed a few ways to achieve communication over the air. Here goes…
The MRF24J40 is a chip developed by Microchip that allows for 2.4Ghz communication over the air. The IEEE standard protocol for this device is 802.15.4 which means that the device is not licensed to be compatible with wireless communications using other protocols such as 802.11.x. The device has 4 available channels open for use. These channels associate to transceiver frequencies at which the device can communicate. We have the ability to hop onto these 4 channels via the RFCON0 register in increments of .005Ghz. Knowing this, and knowing the WiFi standard, it IS possible to hop onto a WiFi network with this device as both have common channels at 2.405Ghz, 2.410Ghz … although programming the protocol would be redonkulous.
So how do you use this thing?I’m glad you asked.
So there she is, in all her freaking particular complexity. I’ll tackle the easy part first. Programming.
This chip accepts all of its incoming information from the host controller via the SPI protocol. The SPI protocol is a 2 wire communications type that employs a clock and data line for one-way communications. For two-way communications an extra wire is needed. So, you say, “what the heck do you call CS(not)! That is another wire!” CS(not) is a signal used to herald across the SPI bus which chip is the intended receiving party of the SPI information. SPI is a little strange in that it is a broadcast bus that doesn’t natively allow addressing the receiver. What I mean to say is that, when using the SPI bus, you cannot simply send out the address of the chip you wish to speak with, and then speak, but rather you must signal the chip you which to speak with, and then speak. If you want a true 2-wire serial bus, look to I2C by Phillips. Long story short, tie CS(not) low with a 10k resistor so that you are always permitted to chat with the chip.
Looking at the datasheet, there are a good bunch of registers that need to be set in order to start communicating. This is how.
Now that you can write and read the short registers, we can set up the chip to start yapping at 2.4xxGhz. These are a few registers that need attention: RXMCR,TXNCON,SECCON0,INTCON,BBREG0…Run through the list of short registers and make your selections.
Now,I must back up and mention the few particular nature of RF communications. The chip and specific requirements in order to speak over 2.4xxGhz. I’ll just speak on what I am familiar with in the following schematic.
L5 and L4 are the inductive managers of the incoming and outgoing differential analogue signal. As we know, it is not possible to send digital information over the air because there is little to none differential in binary information. To solve this we employ a SINE wave whose differential is constantly changing. Electrons of porous material respond analogously to a consistent differential. So, L4 and L5 saturate current during the negative and positive cycles of communication. These inductor values must be calculatedly small in order to react quickly enough at 2.4xxGhz. I’m still a little confused about the tank circuit used to trap the resonant frequency but L1, C7, C23, and C38 contribute to a resonant tank circuit that supplies communications of 2.3215Ghz. Capacitors such as C45, C39, C10… are decoupling caps that ensure a consistent operating voltage.
Okay! I know all of this is uber confusing, but hopefully this helps as an introduction to the chip. This next order of business is to select a protocol stack. There are a few options: ZigBee, MiWi, or if you live in your mothers basement and enjoy D&D you could write your own communications protocol. Next post I will briefly describe the differences.
Apparently, fantabulous is a word. I did not know this. And apparently it is from the ’50s. Interesting…
RoastedToast is back again with a brand-new look and feel!
2010 brings yet another engine powering the site: Wordpress. Previous blogging engines used were (most recently) Blogger, Joomla, Drupal and various others. Let’s hope that Wordpress is the new way to go.
Upcoming posts include a review of Western Digital’s Velociraptor hard drive (model HLFS).