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Wireless Classpad

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#1 vstrasser



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Posted 04 October 2004 - 02:11 AM

Me and some friends of mine, that has a classpad, are interested in develop a digital transmitter for connect two classpads without cable.
The transfer would be implemented by a fm transmitter, working in a not used frequency.
The connections would be performed by 3 pin cable, and get power directly from batteries.

Analising this port, we could see, but not shure (yet), that when two classpads are connected, but no data transfer exists, the level is 0. When a classpad try start a comunication, the level goes one, and waits until the other one responds. At now, seems that this communication is similar to IRDA protocol.

The idea, would be turn a transmitter on for level one and off for level zero. Very simple. There is one problem in this kind of transmittion: the band must be clear, or errors in transmittion could exists. Maybe we implement a tone generator for transmitter, what could helps a lot in this data transfer.

The idea was create a chat to use with this wirelles system. The same chat would allow user send and receive files and variables. But there is a problem with SendVar38K and GetVar38K. The GetVar38K has a big timeoooooouuuuuuutttttttt forcing user stops the program to send a message :(

The Receive38K, that has a smaller timeout, could solve this problem. In the other hand, I could not, yet, establish a connection between two calculators and tranferring data using Receive38K and Send38K

What I need at now:
If some body has a data analiser, like EA200, I need to know how this functions (Receive38K and Send38K) works. Please hooks the connection and records it. This could help a lot ;)

If somebody knows how to implement a connection using these functions, please help me. This would be useful.


ps.: excuse me for my bad english. it is not my native language. if there are errors in my posts, please let me know ;)

#2 CrimsonCasio


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Posted 04 October 2004 - 02:22 AM

im going to take a look at Receive38K and Send38K to see if I can make a real chat program with them, Im not sure exactly how they work but I have an Idea that might work :)

i'll let you know :)

#3 Guest_Guest_mkanter_*_*

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Posted 17 October 2004 - 12:47 PM

the analysis of the protocols is quite easy:
take the fa122 plug it into the classpad and the serial,
write a little (visual) basic program using the serial comm ocx
with some buttons to send fix signals (ready to receive, send, ok, ...).

And then transmit some simple data and analyse it's structure, change the data a bit and analyse the changes...

some info can be get from my site:

the wireless should work like the communication with wires:
an hf generator transmits the signals instead (maybe an lf generator is needed to produce an tone which means active)

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