Cheap wireless (RF) receiver/transmitter solution?

Why do you need radio communication for distances of 25 m ? A network of computers and a simple program is a lot easier, and the students already have laptops, I presume. (The pupils get free laptops to use in the schoolwork when then begin school at 6 years age in my country, and all classrooms have networks built in already)

The simple function you described can be realized with a simple directly wired circuit, if the students have no laptops. Hardware cost is something like 100 dollars.

In short, forget the radio communication, it is extremely unnecessary for the purpose you describe. We are trying to minimize non-important radio communication, because there is too much pollution of the radio frequency ranges.

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Roger J.

Try this.

not a very cheap solution, but it works. we've used it succesfully. Last I heard, years ago, they were testing a low cost/low tech/simple to use unit for K-9, maybe HS students. Their signature system is used by large corporations for voting by their board. We used it on classrooms.

BTW, The Fleetwood Co. is better known for making furniture, go figure!

Also, google for "response system".

Great link. Looks exactly what I would like, but the cost is a bit pricey ($130US per unit for the cheapest unit type).

Will keep poking their site though, see what else they might have around...

P

Hi,

So, the fallback is to create a wired circuit. It requires signifigantly more prep time for each class, and makes demonstrations of the technology a bit more painful. This is likely how I will go, but thought it wouldn't hurt to hit usenet first for some opinions.

As far as I know, we don't give our 6 year olds laptops yet, but one day perhaps (though I hope not). Truthfully, I doubt more than 50% of the students would use them at once during the class anyways, due to the size. Something of a smaller form factor like a remote control or a car alarm remote is what I would be aiming at instead. Pocket pc sized would be acceptable but kind of the largest I would be looking at...

P

Try garage door openers. You can program multiple codes in them and they are available with multiple functions.

73 Gary K4FMX

One student with a finger on the button would probably block all the other transmissions.

Mobile phones? Text 1,2,3,or 4 to this free number etc...

Do a deal with the phone company for special rates to that phone number.

| So, the fallback is to create a wired circuit. It requires signifigantly | more prep time for each class, and makes demonstrations of the technology a | bit more painful. This is likely how I will go, but thought it wouldn't | hurt to hit usenet first for some opinions.

The ultimate logic behind a wired versus wireless system can be identical, meaning there would be no increase in prep time required for each class. The added pain of demonstrating the wired technology is of little consequence compared to the actual functionality of the system, in my opinion.

| Pocket pc sized would be | acceptable but kind of the largest I would be looking at...

I have friends currently developing an in-house solution to a similar problem in a corporate environment. Their solution involves a simple program running on Blackberries, that parses data into XML format and emails it, all transparent to the user.

A program that uses this email technique running on a similar pocket pc is very easy to implement, but of course the cost of the wireless pocket pcs and wireless 802.11 router would be too expensive for your budget.

Your 3 main options are to either go with the wired approach, seek additional funding, or scrap the idea altogether.

--
MT

To reply directly, take every occurrence of the letter 'y' out of my
address.

Yes. they are pricey - now I remember, this was years ago. Talk to them, I believe they have special pricing for schools. The system works, and they had good customer service (directly from them, not the many resellers they had). There might still be competition, I kinda remember a British offering or some other low tech device. I wish I had their names for you. I remember we went through a lot to get alternate sources,and there were some, but we went with fleetwood --- their furniture is so comfy:)

Absolutely. A similar problem is Hot/dead spots. We had that problem with a system in two adjacent classroms operating in the same band. You have to make sure you are not in close proximity to a garage opener testing ground. YKWIM.

I'm not a teacher. I'm an engineer who researched the technology at the request of teachers, many, MANY, teachers that teach for a very LARGE corporation. These teachers said they needed a system like the OP requests, I found one solution for them - the company also makes furniture.

The logic behind it is, AFAI remember, similar to what hapened when I went to school; the teacher asks a question and points to a studnet to answer it - now he knows one student got it right/wrong - but what about the rest of the class? Nowadays, specially adult learning, you get many people in one room and not enough time to querry and interact with everyone.

This system allows the teacher to prepare a test - project it on big screen - querry the class - and immediately see the results for each student (honor system). The teacher can analyze the data and find which students did not understood the material (concentrate on them) or if the teacher sucks and have to explain the concept all over again.

soap box: Every classroom should have overhead projectors, PC and software for presentations, and one such reponse systems, along with the best trained/paid profesionals, along with a few other tools... (slide rule and yard stick:)

Since you'd want to do your data capturing on a PC, perhaps an electronic unit on each unit equipped with an 802.11 interface that has a unique assigned address. Not sure how you'd go about that, but I know that option is there.

Mike

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Does it have to be RF? When inside one room, IR may be an option as well (cheaper and more common)

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The protocol may be complicated: imagine the following situation: the first 2 students answer at exactly the same time, so the signal is garbled and rejected, the answer of number three comes in on its own, and he wins, how unfair ;-) This may be solved by sending a timestamp. Desiging such a protocol and proving its correctness would be a nice academic assignment.

Wim

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Use IR ?

Wim

As a professional software developer, I can say that a client/server environment would be ideal. On the server side, assigning a "test unit" to each student is as easy as keying in the serial number of the unit (which typically would map the IP). Data capture could be done in just about any language supporting socket IO operations. If you (or anyone in the group) can figure out how to make such a unit with an 802.11x module, this is probably a good candidate.

Mike

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There are several companies that make this type of system. Speak to companies that make "audience response systems" or "quiz show systems".

You can even rent them if you want.

Probably too expensive for schools though.

perhaps...

Since you didn't indicate that this was based on some "game" "quick response" type situation, I would go the route of IR. A simple handheld device for each student, with the output configured to send a serial # (uniquely assigned to each student) and then the response (A, B, C ... etc.) You could easily place a couple of receivers around the room and have them all tied into one PC. A simple display board that gives feedback to the students that their response was received would allow them to know whether or not their answer has been registered (I am thinking a grid of lights, one per student that gets reset with every question, assuming that all students are answering every question.) The PC could give immediate feedback to the teacher to indicate whether they understood the material, or, if this is a true testing situation, would give immediate scores. You would also know each student has answered before moving on to the next question.

I see it as a bunch of IR remotes transmitting to 4 or 5 carefully placed receivers, attached to a pc running a fairly simple VB program to tally the results.

Now if you are thinking a gaming system of some sort, most of this doesn't work (ir is too prone to interference), but since you didn't indicate that, I think this will work. The great thing about this layout is you can always add remotes and basically have an unlimited supply of unique serial numbers or number of answers (10 to 16 with most standard keypads), and can cover a larger area by simply adding ir receivers. Each student can keep their own, and you can probably build (buy?) them for $3 to $6 each (small board, PIC, ir led, crystal, a few discreet components) and write the software in a day (or have someone do it for you.)

Just an opinion

-Doug

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RFI would be minimal in this case because the master could poll all the slave units avery ten or more seconds, and very little time would be spent transmitting.

But I would consider another method. Since every student seems to have a cell phone, have them call a number and enter their ID, and then press a key, which can be 1 to 4, or 1 to a hundred for that matter. As soon as the student completes, it hangs up. You could service a lot of students with just a few IVR lines.

But they're all on about the same freq, and would interfere with each other if they were used all at the same time.

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