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Welcome to Cemetech! Since 2000, Cemetech (pronounced KE'me'tek) has been teaching programming and electronics and developing software and hardware. Among Cemetech's specialties are TI, HP, and Casio graphing calculators like the TI-84 Plus, TI-Nspire, HP Prime, and Casio Prizm, embedded and DIY electronics, and computer and web programming. Cemetech provides a safe, friendly space for people to learn, show off projects, and share knowledge and expertise. Our staff of friendly volunteers hang out on our forum and IRC and SAX chatrooms, and are happy to help.
Hands-On with the New Casio Prizm fx-CG50
Published by KermMartian on August 15, 2017 at 11:25:14 PM CST | Discuss this article (4)

Back in 2011, Casio released the Casio Prizm calculator, a revolutionary device that added a bright full-color screen to the classic graphing calculator. It offered 384x216 pixels of space for numeric math, graphing, and user-made programs, powered by a 58MHz processor that could be clocked up to nearly 100MHz. Here at Cemetech, we embraced the calculator, building up lots of documentation and creating plenty of programs. We even wrote a forceful editorial promoting the Casio Prizm over the subsequently announced color-screen TI-Nspire CX, citing the latter's lack of programmability (which was subsequently ameliorated). The Casio Prizm's popularity eventually waned in favor of the admittedly weaker and slower TI-84 Plus C Silver Edition and TI-84 Plus CE, the latter being by far the calculator with the most active set of projects these days.

This March, we announced that Casio was following up the trusty Casio fx-CG10 / fx-CG20 Prizm with a new fx-CG50 calculator. Casio was kind enough to send along a review model of this calculator, so we had the opportunity to go hands-on with it. I outlined my initial impressions in a hands-on review video, while Cemetech administrator Daniel "tifreak8x" Thorneycroft explored the speed of user-made BASIC programs on the new calculator. We found that the calculator represented a significant improvement on the physical design of the older calculator, with a brighter, crisper screen and a zippier experience. On the other hand, the interface remains somewhat unintuitive, and the calculator continues to rely on now-outdated AAA batteries. Among our most important takeaways:
  • Pro: More modern, squarer case design, with attractive white and pseudo-carbon-fiber plastics separated by a thin aqua line, and a more comfortable keyboard, with a few chromed keys as accents.
  • Pro: Iterated color screen, brighter, crisper, and with truer colors (but the same resolution as the fx-CG10/20)
  • Pro: Significantly faster interface, especially for running Casio BASIC programs, as shown in tifreak8x's video below.
  • Pro: New built-in (limited) 3D graphing application
  • Pro: Unrestricted BASIC, C, and SH ASM programming features (the latter two only unofficially supported)
  • Con: Same arguably unintuitive OS interface as the older calculator
  • Con: Necessarily thicker than the TI-Nspire CX and TI-84 Plus CE due to continued use of AAA batteries for power.

The vast majority of our criticisms about the new calculator could be solved by updating the operating system, but we also believe that avid Casio calculator users will find the interface much more intuitive than those of us trained on TI graphing calculators. We just wish there was more official documentation on the Casio BASIC programming language! Are you considering getting a Casio Prizm fx-CG50 for the upcoming school year? For that matter, have you taken a look at our Back to School Graphing Calculator Guide yet? We're more than happy to field questions or comments on Casio's newest calculator in the comments, and be sure to check out our video reviews below.

Back to School 2017: What Graphing Calculator Should I Buy?
Published by Alex on August 6, 2017 at 1:41:54 AM CST | Discuss this article (2)

For the seventh year in a row, Cemetech is excited to bring you a Back to School guide, helping you figure out the best graphing calculator to get for school and how to use it. In both 2011 and 2012, we published trios of guides, showing you which calculator to buy, how to get programs and games onto your calculator, and how to learn to program your calculator. In 2013 through 2016, we held your hand through Which Graphing Calculator Should I Buy?. This year, we once again present a guide to selecting from the baffling array of graphing calculators now available to high school and college students. We'll help you figure out which calculator is right for primary school, high school, or college students, whether you're buying for yourself, your child, or researching for your students.

The landscape of available graphing calculators in 2017 is largely the same as in the prior two years, so we based our selections on the same democratic vote we conducted in 2015, tempered with our two decades of graphing calculator experience. In that poll, we asked our members to vote on the best calculators in three categories: (1) High School Math and Science; (2) CAS (College); (3) Programming. As you'll see in the discussion below, the TI-84 Plus CE released in 2015 (and updated in gold, white, gray, mint, coral, and blue in the last year) was a very popular contender. The TI-Nspire CX CAS and HP Prime also earned high marks. All three of these calculators are accepted on standardized tests like the SAT, and of these three, only the TI-84 Plus CE is allowed on the ACT. We stopped recommending the TI-84 Plus C Silver Edition and TI-84 Plus Silver Edition in 2015, as both of which have been effectively made obsolete by the TI-84+CE (although each is a great calculator by itself). In addition, although the TI-Nspire CX is a fairly popular high school math and science calculator, we feel that the TI-84 Plus CE is a better, easier-to-use choice, and the general student, teacher, and programmer consensus appears to increasingly overwhelmingly agree.

Read the full article for details on the best graphing calculator to buy. Ľ

  • If you (or your child) are a middle or high school student, your teachers may recommend a TI-84 Plus CE or a TI-Nspire CX, in which case you should follow their advice. For high school students getting a new calculator, the TI-84 Plus CE is our favorite choice.
  • If you're looking to take college classes in higher math, science, or engineering, the TI-Nspire CX CAS or the HP Prime are the calculator for you.
  • If you're a programmer, or you want to encourage your student to be a programmer, the TI-84 Plus CE is the best option. It allow BASIC, ez80 ASM, and C programming. The HP Prime also has a very fast BASIC language, and the Casio Prizm (fx-CG20 and fx-CG50) was the original C-programmable calculator.
Good luck with the hectic rush that is Back to School, and I hope this guide helped make at least one decision easier. If you need help picking a calculator, getting games and educational programs for your calculator and onto the device, or you want to learn to program, just stop by Cemetech and chat with us. We're always happy to help.

The Final Verdict:
Now that the three major graphing calculator companeis all offer color-screen calculators, the quiet disappearance of the battery-conserving black-and-white graphing calculator has inexorably continued. Like last year, we are no longer recommending the TI-84 Plus Silver Edition and the TI-89 Titanium, as much as we respect those erstwhile models. Of course, if you already have a TI-83 Plus/TI-84 Plus (or Silver Edition) or a TI-89, you don't need to upgrade to a color calculator yet. If you need a new calculator, we recommend the TI-84 Plus CE, TI-Nspire CX CAS, or HP Prime. Read the full article for details on which of these calculators is best for you. Ľ

From Cemetech Game Projects to Startup: Geopipe
Published by Alex on July 10, 2017 at 9:33:47 AM CST | Discuss this article (10)

I recently sat down with two Cemetech administrators: elfprince13, or Thomas Dickerson, and our founder KermMartian, or Christopher Mitchell. Over the past year, they've been busy working together on their startup, Geopipe. Geopipe automatically builds detailed virtual models of the real world, and licensing these immersive models of the world to architects, urban designers, special effects artists, video game designers, and many others. Geopipe leverages proprietary algorithms to automatically generate immersive models of the world from existing sensor data. They take 2D and 3D data like satellite photos, maps, laser scans, terrain contours, and more, and use machine learning to analyze and understand the data. Their algorithms then reconstruct models at configurable levels of detail to meet the needs of a wide variety of customers. Today, they enter the next step in their quest, a 12-week program called Techstars.

Through this interview we'll see how this idea arose as a challenge that they each tackled in separate environments; Thomas in Freebuild and Christopher in SparseWorld. We'll touch on how the similarities of FreeBuild and SparseWorld brought the two of them together and how the ideas behind each of those projects helped spawn Geopipe.

Here's a video that introduces Geopipe and shows Christopher and Thomas onstage presenting their company to investors.

Read the full interview >>

Accessible Tech: VR and Calcs for the Visually Challenged
Published by KermMartian on July 6, 2017 at 11:45:27 PM CST | Discuss this article (8)

by Thomas Dickerson and Christopher Mitchell

Over the last few years, we have been happy to see an increasing amount of technology designed with accessibility in mind. One of the first examples that we saw was the Orion TI-84 Plus graphing calculator, a modified TI-84 Plus designed by Orbit Research for blind users. When we were at SIGGRAPH 2016 last year, we also VR viewing technology specifically tailored to nearsighted users such as those common in the tech community. We'd like to tell you more about each of those projects, and we'd like to open this up as a discussion about how you think technology can or should be made accessible to more users in the future.

The Orion TI-84 Plus Talking Graphing Calculator

We first encountered the Orion TI-84 Plus back in 2013 at our first T^3 conference. Back over four years ago, Shaun "Merthsoft" McFall described this initial encounter with an accessible graphing calculator: "It was quite an amazing device. When graphing it plays pitches for the Y value of the graph, the same while tracing. When the value is negative the unit vibrates. When on the home screen, it talks out the answer of the equation you enter, and you can put it in a mode where it tells you all the keys youíve pressed. We were curious how easy it was to learn the keypad, and Ken [Perry, a visually impaired user and researcher] assured us that itís very easy to pick up and learn, and that he had no trouble whatsoever." I eventually got an Orion TI-84 Plus of my very own to play with, and found it to be a fascinating tool.

The calculator itself is a classic TI-84 Plus, loaded with a custom OS version, with an extra module semi-permanently attached to the top. I won't exhaustively replicate the list of features we previously published in 2013, but the upshot is that it can speak the math and menus on the screen, as well as make tones and vibrate to represent graphed plots. To demonstrate other ways to visualize graphs, my Orion TI-84 Plus also came with a set of printed, embossed plots that you can feel to "see" the shape of a graphed plot. If you're looking for a full technical teardown, our friends at TI-Planet also posted a hands-on review of the Orion TI-84 Plus for your enjoyment and edification. Since we're a community of DIYers and hackers, they even explored clever ways to play music using the Orion module.

The Orion is certainly a technically impressive tool, and Orbit Research did a great job of creating a module that provides a lot of extra power with minimal hardware modification to the original TI-84 Plus. Perhaps its bigger claim to fame, though, is in its role as a tool for the visually impaired to explore math just as fully as the rest of us. The problem of being able to use a calculator as a blind or visually impaired person is probably something most sighted people would never even consider, but once you think about it, a whole host of problems pop up. First, there's the problem of just doing arithmetic with a calculator in the first place. Perhaps text-to-speech software and OSes' built-in calculator tools could do this, but that's certainly not a good solution for a classroom setting. Then, there's the problem of doing any kind of non-trivial math, working with lists and probability and statistics, and finally, the problem of finding a non-visual way to represent the shape of graphs and plots. The Orion module cleverly solves all these problems, allowing blind or visually impaired users to hear the keys that they're typing, the menus they're navigating, and even the shapes and axis crossings of the graphs they're plotting. Considering the Orion device, and trying to use it with my eyes closed, made me think about so many other technologies that must be challenging or even impossible to use without reasonably good eyesight. I applaud Orbit Research and TI for exploring this, and hopefully in the future more technologies (and at a lower price point) will look to solve similar problems.

VR for the Nearsighted
The Stanford Computational Imaging Lab has a long history of working on problems at the intersection of display technology and human ocular physiology, including the design of an eyeglasses-free display that could provide automatically vision-corrected images to users.

More recently, they've been working to address issues in virtual reality headsets (and other "near-eye displays"). Human vision builds on two separate types of eye movement. When your eyes swivel to look at a new object ("vergence"), they must also relax or contract the shape of the eye itself to alter the depth of focus. In a traditional near-eye display, the physical surface that a user is looking at remains in the same place, and so these visual cues become mismatched from one other, causing visual discomfort and fatigue, as well as potentially more painful symptoms.

At last year's SIGGRAPH we got to test their prototype VR display, using a number of different corrective display modes, including a "monovision" mode adapted from treatments for presbyopia, where one eye is used to focus exclusively on near objects, and one eye to focus exclusively on far objects. While that display, pictured below, is too bulky to be used as a wearable headset in the near future, we look forward to seeing how the technology progresses.

Accommodation-invariant Near-eye Displays

At this year's SIGGRAPH they'll be presenting more fully on those findings, but a short video has already been made available:

In a unification of their work on accessibility and physically-adaptive VR displays, they've also recently published a paper on correcting visual refractive errors in VR, using a hacked Samsung Gear VR, capable of moving the position of your phone relative to the lenses.