Add a dirt-cheap screen to the Raspberry Pi B+ • Hacker News Board

Re: Add a dirt-cheap screen to the Raspberry Pi B+

#61

Post by mdturnerphys » Fri, Mar 06, 2015, 7:35 AM UTC

Crito wrote: post #49

derekp7 wrote: post #39

Earlier quoted context omitted.

Because of cheating? How can you use the Raspberry Pi (in a calculator shell) to cheat, in such a way that you can't use a ti-89 to cheat? Most cheating will be by either storing crib notes on the device (which won't do you any good in math if you don't understand the concepts), or by running a program to solve a problem for you, both of which the ti-89 is more than capable of doing -- that is its whole purpose, is t…

Standardized test calculator rules in this country are not governed by reason. For instance, a TI-89 is allowed on the SATs, but a TI-92 is not. Basically the same calculator, except the TI-92 has a qwerty keyboard. How would a tiny little qwerty keyboard actually give you an advantage on a test like the SAT? Who the hell knows. Remember 10 or so years ago when teenagers were all typing on telephone keypads? On the o…

The TI-92 with its keyboard was banned not because it would help the test taker, but because of a worry that the full keyboard would enable copying the test to send to someone in a later timezone.

Re: Add a dirt-cheap screen to the Raspberry Pi B+

#62

Post by ilaksh » Fri, Mar 06, 2015, 1:14 PM UTC

I can get a whole Android tablet for $60 with higher resolution. Why cant I buy just the screen for $25?

Basically take the tablet manufacturing process and remove most of the stuff thats not a screen and add HDMI.

Re: Add a dirt-cheap screen to the Raspberry Pi B+

#63

Post by paulfurtado » Fri, Mar 06, 2015, 6:30 PM UTC

icebraining wrote: post #46

derekp7 wrote: post #39

Earlier quoted context omitted.

Because of cheating? How can you use the Raspberry Pi (in a calculator shell) to cheat, in such a way that you can't use a ti-89 to cheat? Most cheating will be by either storing crib notes on the device (which won't do you any good in math if you don't understand the concepts), or by running a program to solve a problem for you, both of which the ti-89 is more than capable of doing -- that is its whole purpose, is t…

During my high school exams, every calculator would get reset by a teacher/supervisor beforehand. Harder to do with such a device.

This was still trivial to get around on calculators: on a TI 83/84 you could simply archive any programs you wanted to survive a memory wipe, then un-archive them after the wipe. This trick was widely employed by students in my high school who stored notes/equations by using programs as generic text files.

Re: Add a dirt-cheap screen to the Raspberry Pi B+

#64

Post by Crito » Fri, Mar 06, 2015, 7:18 PM UTC

mdturnerphys wrote: post #61

Crito wrote: post #49

Earlier quoted context omitted.

Standardized test calculator rules in this country are not governed by reason. For instance, a TI-89 is allowed on the SATs, but a TI-92 is not. Basically the same calculator, except the TI-92 has a qwerty keyboard. How would a tiny little qwerty keyboard actually give you an advantage on a test like the SAT? Who the hell knows. Remember 10 or so years ago when teenagers were all typing on telephone keypads? On the o…

The TI-92 with its keyboard was banned not because it would help the test taker, but because of a worry that the full keyboard would enable copying the test to send to someone in a later timezone.

I am skeptical that it would be of any help, particularly since the calculator is only allowed to be out during the math sections, not during the language/written sections.

With the 89's input history, you could effectively record the mathematics section merely by running it all through your calculator and then extracting the history after the fact.

Re: Add a dirt-cheap screen to the Raspberry Pi B+

#65

Post by ChuckMcM » Fri, Mar 06, 2015, 9:32 PM UTC

rootbear wrote: post #42

ChuckMcM wrote: post #27

This is an awesome post. A number of older laptop screens use this "standard" and you can just take off the screen and repurpose it. The trick is that sometimes the flex cable between the screen and the laptop has extra stuff on it. Time to go panel hunting for some more panels :-)

I was wondering recently what the interface is on my old Nokia N800 tablet, for just this reason, but I'm reluctant to take it apart to find out. And I still have a soft spot for my trusty old N800. I also have an XO-1 OPLC laptop, but it has a funky display. Hmm. I have an old IBM T60 in my junk pile, maybe that could be used...

Heh, if you want a matching XO-1 I've got a spare :-)

Re: Add a dirt-cheap screen to the Raspberry Pi B+

#66

Post by chisleu » Sat, Mar 07, 2015, 2:04 PM UTC

tdicola wrote: post #23

chisleu wrote: post #22

Earlier quoted context omitted.

This comes up every time someone mentions the corruption. We don't power off our many pis, but they are on UPSs (we use them for a security system.) However, the corruption happens so much that we keep disk images and have a spare on hand when we have to reboot them for any reason because 1/4 of the time they will not boot up. Even if it were corrupting the FILES being written when hard booted, it shouldn't corrupt t…

> Even if it were corrupting the FILES being written when hard booted, it shouldn't corrupt the FILESYSTEM being written. That's not how SD cards work unfortunately. When an SD card erases data, like if it's updating a file allocation table, it has to erase an entire block of flash and not just the bytes you care about. The card will throw the block into a cache in memory, erase the block, and then rewrite the parts…

I get that, but I don't get how that applies to the corruption we are seeing. We aren't having power fail issues.