Future

After two year's participation in the competition and two first prices at the regional and one second price at the country fair, it's very unlikely that this project is to participate again. First of all not a lot changed since Jugend forscht 2002 thus some efforts would be necessary. Additionally Burkart has finished his first semester at the university and therefore may not participate anymore.

After we found out that TI has developed TI-Navigator, chances are really small that we try and put TI-Net onto the market. Your advantage from this is, that the project is now made public. Nonetheless we will try and further develop our project, especially the software. Hardware development is rather expensive and as of this you shouldn't expect much in that direction.

We summed up some ideas which (if realised) would make the TI-Net even better :-)

If you have ideas we didn't think of, please just drop us a line.

Currently the TIs can only display plain text, fullscreen menus and edit fields together with some text. It is intended to add other content types, like graphics, multi-screen text and the famous TiML.

Wouldn't it be cool to have a PC with tons of games and other TI stuff and just use TI-Net to get that onto your TI? - via radio, of course. Through the use of a microcontroller this is possible and somewhat easy. Problems would arise in the handling: The user would have to select a program from the PC's library and then exit the software just in time to enter receive mode and get the variable from the microcontroller.

Ah yeah, once the basic system is working, it shouldn't be too hard to allow TI<->TI linking.

Browsing WAP or even Web pages on a TI would be the definite killer application. But... First of all only the very basic information (the text) of Web pages could be displayed, a handheld calculator just isn't a full-blow computer with high resolution display and calculation power. WAP is much better in this regard, as it is intended to be displayed on mobile phones with even worse displays. However, to really gain this, the TI would have to be capable of TiML (see above) and the Server software would have to include a WAP to TiML converter.

Hardware is expensive, so why not just connect more than one calculator to one microcontroller i.e. radio hardware? Of course this would make portability worse, just imagine four people with their calcs connected to one radio hardware, running around :-) on the other hand costs would drop by a factor of 4, so where portability isn't that important it'll be worth it.

Some technical stuff: This is possible as the microcontroller has 6 I/O lines free, which would allow for 3 additional calcs, the problem however would be that the microcontroller software would have to be heavily rewritten to do something like multitasking. Also the memory (currently 32kB) would get shorter (then 8kB each calc) and the radio high-level-protocol would have to be modified (not necessarily, but else it would be waste of precious bandwidth)

Probably we ended up "only" being second best at the "Jugend forscht" country competition is because of a bug in the server, which sent an "illegal" packet causing the TI to get totally screwed up. Although each packet features a checksum, damaged packets may also arise due to radio transmission errors (no checksum is perfect). To avoid such errors, content rule checking was invented. The basic idea: Upon receipt of a packet, the TI software checks it for rule violations and according to its importance either corrects it or tells the Server that the packet cannot be displayed. If you take a look at the content ids.txt you will find a huge packet definition for a packet named {error} which would be used if rule violations have been detected. The problem however is, that this hasn't been programmed into neither the TI nor the PC software yet...

It turned out, that the Server software is compatible only to some selected PCs :-) At a presentation at school we ended up with a laptop running Windows XP on which the server crashed, the instant, TXEN was connected to the PC's serial port. Also the used serial port component seems to crash on Burkart's PC when receiving radio noise. Has to be changed...

Currently the TI client software is available for TI-82 and TI-86, but it's intended to port it to at least the Z80-TIs with linkport (TI-83, TI-83+, TI-85, TI-73) and someday also to the M68k-TIs (TI-89, TI-92, TI-92+, Voyage 200). The problem with porting is that we don't own all those calcs (Alexander has a TI-83, his brother an 89, the others we don't own) wich means we can't port, for the Motorola-driven TIs it would even be necessary to completely rewrite the software... Nonetheless we're on our way - and be it that Burkart has to get the whole TI sortiment :-)

Of course TI and microcontroller have to communicate in a way, currently this is a selfmade protocol which is on the low level similar to the one TI uses (see project internals for more on this). The idea is to adapt completely to the TI protocol, as then probably on the TI ROM routines could be used (saves program space) and also variable upload (see above) would be easier/less space consuming on the microcontroller.

Last modified: 05/24/2003 mmddyy by Burkart