Did you know that most TI-Nspires had a LED light at the top of it, besides the USB port?

Well, this LED was added on the regular TI-Nspire, the TI-Nspire Touchpad and the TI-Nspire CAS Touchpad models for exams in North America. Before the test, teachers activate Press-to-test mode (PTT) on the calculator to prevent students from opening any documents or programs. It also disables some functionalities such as geometry. The only way to disable PTT is to connect the calculator to another TI-Nspire or a computer.

While in PTT mode, the TI-Nspire LED flashes between 3 colors to let the teacher know the calculator press-to-test mode is enabled. It also has another signal when PTT mode is disabled. The LED cannot be controlled by any BASIC program or other calculator functions. However, from Ndless programs you can (although on OS 1.4 or higher, PTT mode must be enabled then disabled to remove the protection that TI added in that OS or newer ones). Basically, in a role-playing game, you could make the LED go green when the area is safe, yellow when you are in an area with enemies and red when a random battle is about to occur.

Critor has released a message decoder application called Norse, that demonstrates usage of the LED. Norse is some sort of evolution of Morse language. Alphanumerical characters, commas, minus symbols and spaces are recognized. The character is translated by Norse into a LED signal corresponding to the character in question. Each character are made of 1 to 3 successive LED signals.


(Image from www.ti-bank.fr)

Could this in fact be used outside North America to cheat on tests, the opposite purpose than what TI intended with this feature?

Regardless of if it is used legally or not, this feature might still be useful for certain type of ASM and C games, such as the RPG example mentionned above. Maybe even some sort of Simon Says clone?

More information can be found on TI-BANK:
http://ti.bank.free.fr/index.php?mod=news&ac=commentaires&id=911

You can also download the file there:
http://ti.bank.free.fr/index.php?mod=archives&ac=voir&id=2097

There is also a discussion topic available on Omnimaga, if you don't mind extremly long and technical posts:
http://ourl.ca/8396

ooh! I knew about the LED since the 1st nspire, and wow I must say this would be pretty cool!  Although.. wouldnt you have to memorize the led sequences to decode it upon looking at it?

oooh! nice feature

Wow, awesome. Nice job ruining another of TI's "features." But when teachers hear about this, they'll probably just seat us in a way so that we can't see each other

Quote from: Deep Thought on January 01, 2011, 02:01:30 pm

Wow, awesome. Nice job ruining another of TI's "features." But when teachers hear about this, they'll probably just seat us in a way so that we can't see each other

Teachers will not hear about this, I'm pretty sure, unless if they have a secret spy in Omnimaga and ti-bank.

Maybe they'll notice once everyone in class start looking at the LEDs of calcs during tests?

Maybe I should email T³...

If this becomes widespread, the tests will probably require people to put electrical  tape over the led, like what is currently being done with the IR ports.

I have all internet blocked, so that's no problem for me.

As for the led, I think the only way this is useful is if there is some way a calc itself can read it.  Otherwise, the teacher might notice a person staring at another calculator making notes of which color means what. ;-)

I really don't see the point of all of these anti-testing measures.  If you want to make it absolutely "fair", give everyone a TI-83 or something.  Granted, this could be difficult in some cases, but still.  I took a program called "A" in on a test that just displayed "Does anyone clear ram?".  No one checks this stuff.

I guess it's just me, but I would try and do my best without cheating.  There's no point otherwise.