Slashdot Mirror
Building an Open Source "Clicker"?
fieldtest asks: "Most Slashdot readers have read about "clickers", remote control style devices that students use to wirelessly answer a teacher's questions. Unfortunately, as a college student, I have had less than stellar experiences with these clickers. I hear complaints from my professors and fellow students often as well. So, I want to build an open source clicker system for all universities to use. I believe that this is a prime opportunity to show how powerful free software can be.
So, what do the talented people of Slashdot recommend?"
"The problem is this: a clicker system requires...clickers. What I need are remote controls that have a minimum of 6 buttons (for users to select options with). The sticking point comes when a button is pressed -- the remote must send the option choice, as well as a unique ID specific to the remote, so the clicker software can distinguish between different students.
I've experimented and Googled around. I've tried standard TV remote controls combined with an USB-UIRT receiver, but the range was too low. Googling shows some interesting programmable remotes, but they're far too expensive ($100+) to have each user purchase one.
How should I go about building the perfect clicker and receiver system? Any suggestion is welcome, from IR to radio, from Bluetooth to ZigBee based communications. Recommend a commercial product, or a do it yourself solution. Please also recommend a receiver device, and a way to connect it to a computer. Also, if you recommend that I just build a custom circuit board for the remote control, please give some references and examples of how it should be implemented."
I've experimented and Googled around. I've tried standard TV remote controls combined with an USB-UIRT receiver, but the range was too low. Googling shows some interesting programmable remotes, but they're far too expensive ($100+) to have each user purchase one.
How should I go about building the perfect clicker and receiver system? Any suggestion is welcome, from IR to radio, from Bluetooth to ZigBee based communications. Recommend a commercial product, or a do it yourself solution. Please also recommend a receiver device, and a way to connect it to a computer. Also, if you recommend that I just build a custom circuit board for the remote control, please give some references and examples of how it should be implemented."
www.cypress.com
CY7C601xx
CY7C602xx
About $3-$5 in quantity
Development kit: CY3655 $350
(also check out their wireless USB products)
* Wireless enCoRe(TM) II -"enhanced Component
Reduction"
o Crystalless oscillator with support for an external crystal or resonator. The internal oscillator eliminates the need for an external crystal or resonator
o Configurable IO for real-world interface without external components
* Enhanced 8-bit microcontroller
o Harvard architecture
o M8C CPU speed can be up to 24 MHz or sourced by
an external crystal, resonator, or signal
* Internal memory
o 256 bytes of RAM
o Eight Kbytes of Flash including EEROM emulation
* Low power consumption
o Typically 10 mA at 6 MHz
o 10-A sleep
* In-system reprogrammability
o Allows easy firmware update
* General-purpose I/O ports
o Up to 36 General Purpose I/O (GPIO) pins
o High current drive on GPIO pins. Configurable 8- or 50-mA/pin current sink on designated pins
o Each GPIO port supports high-impedance inputs,
configurable pull-up, open drain output, CMOS/TTL
inputs, and CMOS output
o Maskable interrupts on all I/O pins
* SPI serial communication
o Master or slave operation
o Configurable up to 2-Mbit/second transfers
o Supports half duplex single data line mode for
optical sensors
* 2-channel 8-bit or 1-channel 16-bit capture timer. Capture timers registers store both rising and falling edge times
o Two registers each for two input pins
o Separate registers for rising and falling edge capture
o Simplifies interface to RF inputs for wireless
applications
o Internal low-power wake-up timer during suspend
mode
o Periodic wake-up with no external components
* Programm
"Is life so dear, or peace so sweet, as to be purchased at the price of chains and slavery?" - Patrick Henry
Alright.
First, a normal infrared remote won't work. You'll need a custom programmed microcontroller remote and a receiver to handle such. In order for the receiver to detect all the remote's answers (given a one way system) each remote, when the button is pressed, would send its message, pause a random amount of time, send again, pause random again, etc. This would go on for a second or so during and after the button press so the receiver has a chance to catch it in the midst of all the other remotes sending their data. The data burst would have to be *very* short to increase the bandwidth and decrease the collision rate.
A one-way RF system would be very similar.
If you do a two way radio, there are a few more options. Ideally you'd do a two-way network (such as zigbee) since it would be very expandable - it could accept a variety of clickers from the simple credit card remote to the full keyboard and display.
A simple 2.4GHz custom network could be designed using Nordic Semiconductor's nrf series of chips. The nRF24E1 chip would be perfect - includes microcontroller, 2.4GHz transceiver, and is very low power.
-Adam
Clickers are a solution looking for a problem.
In fact, research has shown that using clickers to help enable "Peer Instruction" techniques can greatly improve the quality and durability of learning.
Hopefully, some empirical evidence outweighs what you think ought to be true.
Well, the last time I chimed in with experience from lecturing, I was modded down "flamebait" -- but I'll come back for more. The clickers (in my experience) really help the middle third of the class -- the people who aren't coming back as majors, and therefore will only learn whatever they glean from this particular class: it is the last time they will encounter this material formally.
The future majors will probably do just fine anyway -- it's the history majors in astronomy class, or the engineers in art history class, who need help. The clickers have been shown to help those students focus and assimilate material.
It's actually unbelievably odd that I saw this article up here on /. I am a CS major at RIT(Rochester Institute of Technology) and there is a pilot going on here with a few teachers, using a "clicker" to answer multiple choice type questions during the lecture. I find that the clickers are a great idea, inspiring more students to answer questions due to being anonymous. It totally eliminates the blank silence after the prof. asks any sort of question. As a matter of fact it actually helps hold my attention more and really lets the teacher spend more time on the topics people aren't understanding rather than what he thinks students should understand.
But there are some drawbacks, one primarily being the cost($60 is awful considering the other expenses associated with class), and the other being that the technology is in it's infancy and the software is definitely a few releases from being truly ready for primetime.
This technology can really take off, if the clickers become a part of the desks, or worktables or whatever and are totally funded by the university. Ultimately the price and the glitchy software will hold this back from being well implemented in schools even though it has some clear advantages.