If i converted the price right each nit costs under $33 US, however that might not be true, because the prices of the components may be different. Also use of the product might not be legal in the united states, due to fcc regulations. however it is a really neat concept.

'nit' should have been 'unit'.

Hi !

Component's price are very high in France, so the cost is probably under 30$ for many countries.

About FCC regulations : 433.92Mhz is a free frequency, legally you can broadcast only 6 minutes/hours (10% of time). Output power is about 10dbm (10mW).

Maybe I'm just not quick enough to understand it, but how could this illegal? Why would the FCC care what we are doing with our calcs? Would it have something to do with linking interferences or something?

The Federal Communications Commission has complete control over all frequency bands in the U.S. It is there job to enforce that certain bands are restricted to use by government, intelligence, commerce, etc. For this reason they must set limits on the amount of power that can be used for transmission as well as what frequencies can be used and by whom. Luckily the frequency band chosen for this application is a free band meaning that anyone can use it so long as the power of the transmitted signal does not exceed a set limit. The same organization (FCC) is the reason that you must turn off your cell phone when flying in an airplane. I'm sure that you have heard of WiFi or 802.11a,b,g. These all use free frequency bands which is what makes wireless networking so great, although troublesome at times.

wireless networking is great... in fact, i'm using it right now to browse the internet and to try to find a pic876.. which i can't seem to find

Try the link above. That should allow you to order direct from Microchip. You may be able to get a better price at digikey or elswhere though.

i still can't find it anywhere..

I've often wondered why you're supposed to turn off cell phones on an airplane. I think they also prohibited the use of any electronic devices during take-off, but it's been a while since I was on a plane.

Well, it's good that this thing is legal... if it wasn't, then that could be bad. :)

Electronics durring takeoff is for saftey.

The real reason they dissallow Cell phones is that when you are that high up and moving that quickly you would be switching towers vey often, this could thoeryeticly cause a free call, but could also increase the price of the call, The calls could disconnect suddenly etc. (This was from a reliable news article in one of the magazines I read.)

I am not certain that it is an FCC regulation, but i'm fairly sure that it is not an FAA regulation.

No. It can cause signal interfeirence with the navigation controller last time I checked.

Uhm... 802.11b and g run on one of the most crowded frequences of all, 2.4 GHz...

So, we're either using different definitions of 'free' or...

Clarification: Are you saying free as in available for use or as in not taken?

Free frequency means that the FCC does not reserve it for a special use like a radio station or some government thing. You dont need a special license do brodcast on it too. But you are limited on the amount of power you can use.

Ok. I was just checking 2 see how you were defining it.

There is also the potential of interference to the amateur service since 433 MHz lies in the 70cm amateur band.

It runs on radio signals, does that mean one could broadcast a program over an AM radio station to be recieved by people with 2.5 mm -> 3.5 mm stereo cable adapters?

Why would you need an adapter?

The person above is talking about being able to broadcast a signal ove an AM frequency and then others could tune to that station and then they could plug an adapter(you need one because the headphone jacks on stereos are too big for a ti link cable) into the headphone jack and be able to receive information that way which I think would be pretty awesome!

Hi!

It's not possible to broadcast over AM Radio, transmitter is integrated into Aurel's module, so you can't demodulate signal with radio.

drat!

How much bandwidth is it per user on your device? Or do all users share the same band gap? Also would you consider implementing some kind of a CDMA or TDMA to get the number of users to increase?

For the moment, this is the version 1.0, only 2 calcs can chat' together, this an half-duplex communications. Therefore, you can try to connect 3 or more TIs : all datas sent by one, will be sent to all TIs (not recommended).
Acutally i'm searching to implement network, but i don't have so much idea about how to do this. Is someone can help me ?

Sincerely

It seems that if we wanted to do a MIMO (multiple input multiple output) we would need a DSP. The overhead would be pretty high and it would definately be huge project. Basically cell phones are just now (since 1990's) using CDMA. Every user is given an orhtogonal code that his signal is multiplied by. In this manner all users share the same frequency band...massive interference. However through using the orthogonal codes the signel that is received by the "server" can use another algorithm to seperate the signal into the individual signals from all users. It is pretty complex and may require an ARM processor, but I'm sure there are other less advanced techniques that could be explored.

Very interesting topics. But i plan on Ethernet-like protocol or simply a master/slave protocol to share connection.

If someone has some idea about it...

talk to kerm martian, he's the expert of calc networking

No,don't ask Kerm. He's the expert of projects that don't get finished.

I think experts of unfinished projects are usually the very knowledgable ones. I think asking kerm martian is probably a good idea, since he's an expert on calc networking (I don't know that for myself...just referring to RCTParRroThEaD_ above).

See link for all the stuff Kermie Hasn't finished.

It woln't work properly... and thats if it even works @ all...

I'm not sure if this store is nation (US) wide, but a place now called Mar Vac Electronics sells electronics kits. One of them allows transmistion to either the AM band or FM band. Just allow for the imput to be from the calculator instead of a microphone and then people can use the radio to link. Only problem that arises is the static being converted into "data".

Not quite true, from what i can tell the reciving calculator must be able to contact the sending calculator, stating that it recived the transmition.

I forgot that the circuit was one way, thanks.

Yes, that is if you use TI's protocal. But if you just have a low-level recieve set up you could skip that. My other comment was suppoesed to read "I forgot that the kit was just a transmitter"

Thanks for the explaination... that's exactly what I meant.