Category: hardware
Arduino Microcontroller
hardware : by Tommy — May 25th 2009, 01:15AMFirst of all, the Arduino is an open, "free" (as in beer) platform running atop the plentiful (and cheap) Atmel AVR microcontroller line. The open nature of the platform allows each revision of the platform and IDE to improve. The current 2009 model is very easy to use. The documentation is pretty good and (imo, best of all) it uses the C programming language. This rounds off the learning curve quite a bit since I have more than a couple years working with C-style programming languages. Now I don't have to fool with BASIC or assembly. I really disliked the patty-cake approach that the BASIC Stamp provided (i hate BASIC), it's easy to get bogged down in assembly, and most C-compilers for microcontrollers are well over $200. The BASIC Stamp pales in comparison to the Arduino in just about every category. The Arduino is cheaper, faster, offers libraries and has a much wider audience than the Parallax BASIC Stamp. The PIC and standard AVRs have a relatively steep learning curve and is easy to get buried in the syntax.
The Arduino abstracts quite a bit for you, freeing you up to be creative and rapidly develop whatever interests you.
What's interested me lately is parsing the WWVB atomic clock signal from Ft. Collins, Colorado. Thanks to a C-Max CMMR-6P receiver chip that I got from DigiKey, I have a data stream going right into my Arduino. A little bit-twiddling and voila I now have the exact time and date. I dug up a couple of old HD44780 LCDs and now have the time displayed. Next up will be the addition of a Real Time Clock chip to hold the current time, maybe the addition of temperature and barometric pressure sensors and I'll have a neat little info station. More on that project some other time.
I also bought an Ethernet Shield so maybe I can share my future project(s) on the interwebs. There's so much that is possible, I can't recommend the little microcontroller highly enough. Check 'em out, they're only $30!
The real cost of SMS.
hardware : by Corey — December 28th 2008, 10:26PMBut first, some nomenclature! The technical name for a text message is SMS (Short Message Service). It was designed and originally codified for use with GSM networks and devices during the 1980s. It consists of a short message, usually 160 total ASCII characters or less in length, transmitted between devices.
Another term thrown around is control channel. The control channel represents the very small piece of RF spectrum that is always active and serves as the, "always on" link between your device (usually a phone) and the network. All network information is transmitted over the control channel, including what RF channel to use and at which power setting to operate. Additionally, it is used to transmit paging messages, which is also why the control channel is often called the paging channel. Those page messages include alerts about incoming calls, outgoing calls from your device, incoming call waiting calls, network alerts, and other network/device communications. The other channel is called traffic channel, and is utilized when a call is made (either voice or data).
With that in mind, the central point of most of the articles published about this story is that SMS utilizes the control channel of the network, which does not require a traffic channel connection to be made that takes up valuable spectrum on a particular sector of a cell phone tower.
This point is flawed. Specifically, SMS messages are designed to roll over to the traffic channel any time the control channel is too busy to handle the additional traffic. This happens regularly in large cities during peak usage. Moreover, on non-US networks where the SMS size is greater than 160 characters, those messages are usually sent over a traffic channel. In CDMA, all devices have a setting that can force the device to send all SMS over the traffic channel if the carrier so chooses.
To be clear, most text messages are sent over the paging channel. But it is important to understand that SMS is not limited to use of the paging channel. The message must run through the SMS Concentrator (SMSC) and is then transmitted over wired networks, and often the Internet when sending messages from one network to the other. They are small, but they are utilizing network resources. And that does cost the carrier in terms of bandwidth and infrastructure. When that message has to be transmitted over the traffic channel, that message takes up a slot on that sector that cannot be used for other data calls or voice calls. That doesn't seem like a big issue when looking at a single sector, but if you weigh in the traffic on a national network, it does start to add up.
Now, carriers are of course screwing over the customer at any possible turn. Though the carriers do have some costs, the economies of scale they enjoy from a network infrastructure standpoint render those costs infinitesimal at best. So why have they doubled their rates over the last year? Simple: to pay for everything else.
Voice networks are not generating the revenue they used to. They used to make a lot of money off ringtones and pictures, and while that is still a viable market, it isn't what it used to be either. The real issue here is data usage. The amount of data used by subscribers is very significant, especially for EVDO Rev. A users on Verizon and Sprint. Both of those carriers have rolled out ridiculous limits on the service, such as Verizon's limit of 5GB per month for $60. Prior to these limits, they were virtually no gauges on data usage, and it was the same price. The huge margin they enjoy on SMS helped offset the loss of margin in voice and data services.
Another reason is that the consumer is willing to bear the cost of the service as offered. If people didn't use it, they would lower the cost, but text messaging is (lamentably) growing in popularity. That's a classic example of supply and demand at work.
Without a doubt, carriers are screwing over the consumer. They charge outrageous fees for services in order to maintain margins. That's right boys and girls, not revenue, but margins. The revenue continues to cover operational costs, but margin has been adversely impacted. A synonym for margin is profit.
They're all greedy jerkfaces. and I'm all for Congress investigating these companies for failing to compete, but the problem with that is that the only body we have responsible for this is Congress. I suppose time will tell, but I don't expect anything to come of it that favors the consumer. What say you?
USB CueCat
hardware : by Tommy — September 18th 2008, 10:51PMRecently I purchased a USB model of the CueCat. I had no idea USB models were ever available, but I found plenty of online sources selling them. I bought mine from mavin.com. I just got it in the mail this afternoon and was able to "declaw" the cuecat in about a minute. The process of declawing is simple enough and, in short, it allows the cuecat to output only the barcode information in plain text (versus an obfuscated and "proprietary" format). After declawing I can now use the cat to scan any barcode. I hope to use it for cataloging any books I own, as well as selling used textbooks online after each semester.
Grendel sez: Neat, but otherwise useless, I've learned that Google will take UPC numbers and link to various UPC databases to tell you about the item you just scanned. Interesting.
update: 10/30 - Apparently the patent for :Cuecat was still outstanding until recently.
New Motherboard Time
hardware : by Tommy — August 21st 2008, 11:29PMSince I've been out of the hardware scene for a while, I'll open up discussion on what's hot now. Remember, I'm not a fan of "bleeding edge", I'm looking for best bang for the buck.
Update: Ok, so I didn't go the performance route, but I think I got a modest computer setup. Maintaining about the same performance before the motherboard went out. I found a deal on a dual-core AMD Athlon X2 Brisbane for $30 shipped, so I decided to bump up the CPU a tad. I went cheap on the motherboard because, frankly, I don't need a whole lot. I settled on the Asus M2N-MX. Because my old RAM wouldn't work on new boards, I got 2Gb of OCZ DDR1066. The machine is functioning again, all systems are go and I'm back online at my regularly scheduled times. Thanks for all of the suggestions. I'll prob be ready to upgrade this "value" setup in a year or so.
(total spent: ~$130)
