Posted by Deliverator on 12th April 2006
I have been playing around with the 3w Luxeon Star emitters that Lumileds sent me in conjunction with some very neat LED regulator/limiter circuits from Taskled. The Taskled regulators are a very neat piece of circuit design and layout, fitting on a circuit board about the size of a quarter. Couple an emitter with one of these regulators and a watch/coin type lithium battery and you have got a blindingly bright flashlight that can fit on a keychain. The chief limiting factor of a such a bright light in such a small package is the heat.
LEDs are very efficient light sources, but a 3w LED still puts out a fair ammount of heat. My full sized, 7 watt Luxeon flashlight has a solid metal body and will get quite warm if you leave it on and aren’t holding it (your body’s circulatory system whicks away the heat from the flashlight body). In the case of my “micro” sized 3watt flashlight, the only metal heatsink is the hexagonally shaped metal “star” to which the actual LED emitter is mounted. This heatsink gets pretty warm in about 15 seconds of use, so you couldn’t use a flashlight like this for very long before risking burning out the emitter from overheating. If one housed the components in a small metal box, one could probably use it for 2-3 times as long without increasing the overall size much. Still, there are a lot of uses for a small, very bright flashlight.
Most of the situations for which I require a flashlight don’t require the light to be on for more than a few seconds (i.e. lighting the stairs so one doesn’t trip, finding the keyhole on your car, etc.). One odd thought that crossed my head after being half blinded by my own creation (with bright purple spots floating in my vision for several minutes!), is that it should be possible to create a very small, non-lethal, personal security device that simply temporarily blinds an mugger/attacker/rapist/school bully/whatever. I am not sure about the required intensity, but my guess is that an array of maybe a dozen emitters would do the trick, particularly if they were highly over-driven (supplied a higher voltage and current than is optimal for long term emitter life).
I have plenty of LEDs with which to experiment, but only have 5 of the taskled regulators. Each regulator is capable of driving two LEDs, if one swaps out a single surface mount resistor (replacements thoughfully supplied by taskled). Sounds like an interesting project for a rainy day.
Posted in General, Tech Stuff | No Comments »
Posted by Deliverator on 8th April 2006
I have been rather displeased with the recent crop of PC video games, in particular the whole FPS genre, which increasingly dominates store shelves. I recently played F.E.A.R. to completion and at the end was left with the fealing that it should have been something more. The one thing that fear really had going for it was atmosphere. The sound effects were terrific and the designers made much better use of shadows/lighting to set the mood (unlike Doom 3). On the whole, though, many fundamental aspects of the game felt wanting. In particular, the few “puzzles” in the game were far too easy to solve and the almost invariant way in which voicemails and laptops were used to move the story along, really made me feel like the game was just a series of levels that had been stitched together, with a veneer of a story pasted along the top at the last minute. Half Life 2 (and HL 1, for that matter) did a far better job of revealing aspects of the plot through more subtle hints placed in the environment. In Half Life 2, it was easy to believe in the world that the game designers had so meticulously crafted. Fear, to me, just felt like a pointless exercise in FPS mechanics. Frankly, the whole FPS genre has gotten rather stale, and it is a rare game like HL 2 that stands out in the faceless crowd.
So, in lieu of playing yet another hackneyed FPS, I have been playing a number of classic computer adventure games from Lucasarts and Sierra. Thanks to platform agnostic game interpreters like ScummVM, I have been able to play many of these games on my Netbook Pro. Rather than taking a trip down nostalgia lane, I decided to start playing games that I’ve heard great things about over the years, but had never played “the first time around.” I started with Sam and Max Hit the Road and followed it up a couple days later with The Secret of Monkey Island. It took me a couple of days to complete each of them, and I confess I had to use a walkthrough twice. Some of the puzzles really had me pulling my hair out (but in a good way!). The sheer goofy inventiveness of these classic games has really been a breath of fresh air for me.
Sadly, adventure games have all but disappeared from the PC marketplace. I had a memerable chance to visit with legendary game designer Roberta Williams shortly before Sierra went poof for good after a series of bad mergers and corporate malfeasance. Ken and Roberta have more or less wiped their hands of the PC gaming genre (and fell off the earth for a number of years), but some of the great adventure game designers are still plugging away and fighting the good fight. Notably, Tim Schafer, who helped create some of Lucasarts most popular games (including Monkey Island), has started his own company, Double Fine Productions, which has come out with a very highly regarded new game called Psychonauts. Psychonauts, despite all the critical acclaim, is very hard to find on store shelves. Thankfully, due to the miracle that is the interweb, you can order it online.
So, if you are as disgustipated as I with the state of modern gaming, try downloading a classic adventure game from Sierra or Lucasarts. Your sense of whimsy will thank you.
Posted in Gaming, General | 1 Comment »
Posted by Deliverator on 8th April 2006
I was able to fix the CVS video cameras that we used with minimal success to capture “on robot” footage at the PNW regional. I think that the experiment that Ryan and I conducted on building a linear voltage regulator (to run them off the main robot battery, rather than on internal AA batteries) scrambled the firmware somewhat, resulting in the periodic hard lockups we encountered at PNW. I was able to acquire a fresh firmware and reflash the cameras. Each camera has now captured over an hour of video and they haven’t crashed once.
The original “robocam” footage from Portland is available elsewhere on my blog.
Posted in General, Photography, Tech Stuff, Titan Robotics Club | No Comments »
Posted by Deliverator on 3rd April 2006
I’ve heard from many PPC owners that the Xscale series of processors are often very conservatively clocked. Most PDAs don’t need a whole lot of processing power for the tasks they perform. I believe that the first couple generations of palm pilot, for instance, were 16mhz Motorola processors, and almost all the applications I used to run felt quite snappy compared to their PC equivalent. Today’s PDAs seem to be clocked at between 300 and 600 mhz and are almost universally Xscale/Strongarm processors at this point. My needs are a bit more demanding than the typical PDA user, so I decided to see if I could overclock the Xscale PA255 processor in my Netbook Pro a bit. I managed to find a overclocking utility for the Xscale processor. The application is in japanese, but is fairly self explanatory, and full source code is included, so it should be possible to create an english language version. The application was designed for the NTT Docomo Sigmarion III, a japan only HPC that has gained a cult international following despite the japanese only Win CE OS version. The utility works fine on my Netbook Pro and is reported to run on the NEC Mobilepro 900c as well.
After some mucking about with the utility and some nominal overclocking just to test that the utility was actually working, I decided to put my Netbook Pro through its paces. I gradually increased the clock speed and benchmarked and looked for signs of instability at each progressively higher clock speed. I ran timedemos in quake, a video benchmark using TCPMP, ran the BMQ benchmark suite and calculated PI out to a rediculous number of digits. All the while I watch for signs of overheating (visual artifacts, hotspots of the case, weird smells, smoke, etc.) and found none. I also checked to ensure that the Netbook Pro’s CF, SD and PCMCIA slots were working properly. On my Strongarm based Jornada 720, I found I could overclock the unit, but that the expansion slots would stop working, rendering any overclocking of limited utility. On my Netbook Pro, I had none of these difficulties and was able to stably clock the unit to ~800mhz, double the units manufacturer clocked speed!
I am not sure how badly battery life would be impacted at this extreme speed, but I noticed no stability issues while running at this speed. General system navigation was perceptively snappier, and every quantitative indication of performance increased substantially. BMQ returned very high scores, with only an overclocked Sigmarion III scoring higher overall, due to its dedicated video processor. I would like to plant a thermistor on the CPU and get temperature readings at different speeds before overclocking on a more or less permanent basis, but am a little wary of cracking open my rather expensive Netbook Pro. All in all, I am quite impressed with the overclocking potential of the Xscale processor. Not since the mid 300 mhz Intel Celeron processors can I recall a processor that so easily overclocks to nearly twice its default clock speed.
Posted in General, Portable Computing/Gadgets, Tech Stuff, Windows CE | No Comments »