Teacher Notification setup

Hey all! I'm dreaming up a system that goes something like this. It is very similiar to an Andon light used in the manufacturing world.

  • Each student has a switch on their desk connected to an LED.
  • When the student is working away just fine, the LED is set to green.
  • When the student needs help but can continue working, the LED is set to Yellow.
  • When the student needs help and can not continue, the LED is set to RED.

The trick is that I want to read the status of the lights from a "main console" which will probably be just a PC in the corner somewhere gathering data wirelessly.

My thought is that data can be compiled to show a variety of information such as: which students are doing well, which students are getting along, and which students are falling behind. Also, one could take the data and compare it across multiple years for certain lesson plans to find out which are working and which are not. Etc, Etc.

So my question to all of you is: What hardware do you think i should use to transmit the current state of each desk? I'm thining that xbee + arduino might work, but the cost of that scares me a bit. I'm wondering if a simple RF connection would work? There are about 30 kids per class, so cost is definitly an issue here.

Anyway, I'm anxious to hear what you all think.


I've seen this used in Second life, and it fails to be utilized for a simple human issue.

If people are having issues, they don't always want others to know that they are having issues.

We've found consistently that a signaling device that allows others around you to identify you are having issues causes users not to use them.

I know this sounds a bit bubble bursting, and I hate to ever tell someone to think up something different, but singling out students is horrible when its done in front of their peers.

Do you want to be the only person in class with a red light above them while everyone else's light is green?

I think the idea is sound - its our prides that get in the way of our learning.

Instead of a pole with 3 lights on it, perhaps just your screen in the corner with desk numbers setup like restaurants do. If desk#4 presses button, an event is sent to the screen to indicate #4 needs assistance. You could use a single Xbee to an LCD with a pager vibe to make it portable so you wouldn't have to run to the PC all the time...

BRuTus - thanks for the response man!

I definitly see what you're saying and in most cases agree with the idea that pride is a major barrier to admitting you need help, especially with adults! This situation is a little different though.

The subject is reading/writing, so a block of time each day/week is set aside for students to work independently on their current writing project may it be a journal entry, a topic paper, or otherwise. So the questions aren't necessarily "I don't get it" but more like "I'm thinking about doing XYZ could you give me feedback"

Two signaling systems have been used thus far: - Students simply raised their hands, - The current system of having 3 different colored index cards that hang off the front of the desk.

Both of these work, but both have their problems/limitations.

From a data mining prospective the idea of capturing what students had issues and when, is very interesting to me. I agree that the andon light might not be necessary and could be cut in favor of a restaurant style notification system, but to be honest I think the kids would really like them!

Then the only question I have is what are your thoughts on powering each desk? Batteries or some sort of cable?

If you are going to run a cable for power, might as well make it a cat5 cable and just throw an ATMega onto each station connected via I2C. Last leg into PC.

3ea 10MM Diffused lens LEDs should look nice if mounted in regular ABS plumbing pipe. Use two for each color, one through front, one through rear.

You can get really fancy and only light up each color at 65% initially and every minute jump up the brightness by 5%.

I like that idea! Increasing the intensity preportional to the time! Excellent.

I am hoping for a solution that incorporates rechargable batteries. Not sure what size because I'm not sure what wireless hardware to use :)

I'm thinking they will be "docked" at night on the counter and when the students pickup their writing folders off the counter they will grab one of these devices. Then, when they bring their folders back, they will set them in the cradle, where the device will be charged and ready for the next go-round.

That's going to take some serious thinking.

Not sure what cheapest RF data comms would work best here.

IR would be tricky for multiple data streams... something like this would work, but you're going to end up with one heck of a mess of software on the other side.

You could just as easily repurpose this, but cost is not cheaper than XBee. (Although Dev time would be, since each transmitter/receiver pair can be coded uniquely.)

Anyone else have some thoughts?

I've been informed that IR would work not to badly.

You could help cut down collisions by having multiple receivers (Maybe one for each row of desks?)

Each transmitter (The Student unit) would just broadcast it's unique ID when it student presses button. broadcast a couple of times to ensure message received, and delay in between. Also have a little IR detector in each so they wait their turn to broadcast when someone else in the same row is transmitting.

To acknowledge assistance is being given, teacher has a unique FOB that when button pressed issues a set pattern to the student's IR detector.

The actual IR emitter can be located in the Andon pole clone.

To make it inexpensively, I'd look into building the "poles" with something like an ATTiny AVR or a PIC, a transmitter like this one, and a single RGB LED. The same ebay seller has cheap receivers, too.

Each CPU would be programmed with a unique ID, which it would transmit multiple times for redundancy whenever its state changed. There would be some collisions, but careful design should come up with a protocol that would pretty much ensure delivery without the expense of 2-way communication (although an IR "broadcaster" on the ceiling might do the job cheaply).