I was planning on doing this with my clicker as well (brand: einstruction). It runs a Motorola cpu with a separate RF chip and firmware is on a eeprom. It also has 6 test pins labelled PROG in the battery compartment.

So after a good number of correct answers are received you make a transceiver auto-answer for you. You first need to record your own transmitter ID by pressing a special combination and then just fake pressing a button for each question. Somehow this feels like cheating.

@DarkFader

because it is cheating.

No, it really is cheating. Sometimes, “Working the system” IS cheating.

BTW, I am happy to see some real math here at hackaday.com: “…repeat the answer that was most often sent for the quizzes…”. A subject interesting enough to launch a short on last season’s NOVA Science Now:
http://www.pbs.org/wgbh/nova/sciencenow/0301/04.html

Basically the story goes (from wikipedia.org): “In 1906 Galton visited a livestock fair and stumbled upon an intriguing contest. An ox was on display, and the villagers were invited to guess the animal’s weight after it was slaughtered and dressed. Nearly 800 gave it a go and, not surprisingly, not one hit the exact mark: 1,198 pounds. Astonishingly, however, the mean of those 800 guesses came close — very close indeed. It was 1,197 pounds.”

Dry, I know, but this sort of stuff props up the notion hackers do think from time to time.

To answer the question about why secure encryption hasn’t been added to these clicker systems, it’s mostly that A) these companies don’t typically feel student users would be smart enough to hack them and B)the typical user would only have his/her hands on one for less than an hour unless it was snuck out of classroom without permission.

Given the expense of these systems and the cost of replacing even one clicker, I’m surprised anybody with legitimate access to one actually decided to tear one down (let alone the numbers I’ve read about here). Mostly, the only way for an average hacker to get these clickers is by theft or “borrowing” from a classroom’s set.

From a teacher’s point of view, while I’m happy to see some students thinking, hacking and doing the math and programming needed for this project, I sure hate the idea of instructional funding possibly being abused since it’s so hard to come by.

it would be great to have an open source clicker system (i-clicker claims to be, but i have never seen any source code).
it would also be useful for class room use: with a free protocol at the base station, clickers could be used for anything one could script!
group the clickers and show group progress, have different students answer different assignments, sign up for different assignments using clickers..

i’d really love to see an open clicker system. with an open source base unit, one could even use it at home as a long range remote control, to control the lights or the sprinkler. and
the cheating problem could be taken care of with an asymmetrical encryption system

Why do people still use the 8051? While the communication is dead simple, he was able to extract the entire rom from it. Its much harder to do this from a fused locked PIC or AVR. (Not imposable, just harder)

Hell, even a TEA encryption using the serial number would be preferable. Very least you can’t real-time decrypt it for tests:P