Hi,

After I saw the very first very the interactive table, I started working on something similar. Since I'm not really into electronic stuffs, more into software, the first think I wanted to do was to implement the "water effect". For this, I need a microcontroller, and a led driver. I only started trying to make a JDM programmer recently, then I've found that you have now a more advanced (and kit aviable) design, so I wanted to know if, with your experience, you think my design may work :

-I will use a pic18f4550 (because it is the first think I'll be doing with pic, I wanted to buy one with USB and many I/O pins so I'm not limited, also I4ve made not estimation of the computing power I need so I choosed a 48mHz pic18)
-I will use tcl5940 led drivers, those driver can be cascaded, and can each handle 16 lines of up to 80mA.

So with one pic and four of those drivers, 64 independant lines of leds can be driven, making a 8x8 matrix for the water effect. This mean it would requier (for 640 leds) 10 leds per line, which mean a 30-35V power supply.

Another reason why I'd like to make a pic based thing, is because I hope (if I have enough CPU power) to make a dopler effect sound localisation system, so the table (which won't be a table but a roof in my case), can react to speaking people, footsteps, ...

Any comment ?

I'm not quite sure what you mean by "water effect," and I presume that you mean the tlc5940, not tcl.

Anyway, a PIC and LED driver can be made to work, isn't the only way, and isn't the way that I'd do it.

I'm not sure that I see your specific reasons for choosing PIC over other platforms-- looks like you're using the choice of the PIC platform to drive the other choices, so you get what you get: If you're happy with it, great!

>I'm not quite sure what you mean by "water effect,"

There was a link to the water effect exaplaination in my first message, but it seems taht links are displayed like normal text here http://www.gamedev.net/reference/articles/article915.asp

>and I presume that you mean the tlc5940

yes, because I have them ready. People interested in this soultion should have a lookg at the 5942 (nearly the same chip, only 80mA instead of 120, but eeprom can be programmed at low voltage, it does not requier 20V)

>and isn't the way that I'd do it.
>I'm not sure that I see your specific reasons for choosing PIC over other platforms-- looks like you're using the choice of the PIC platform to drive the other choices

As I explained before, I've playe a few time with electronics, but I really more a business analyst and java coder. So what lead my choice was the way that I'm stronger with coding than with creating things out of resistors and condensators, and my lake of culture in this domain (maybe other µC are better than pics for this purpose ?)

Another question I asked myself, is if you consider the intereactive table an "open" project. I mean, do you mind if I other people make website giving details on how to make one from scratch (I don't really think so because you website already give so much information, but I prefer to be sure) ?

Regards,
John.

>As I explained before, I've playe a few time with electronics, but I really more a business analyst and java coder. So what lead my choice was the way that I'm stronger with coding than with creating things out of resistors and condensators, and my lake of culture in this domain (maybe other µC are better than pics for this purpose ?)

If you are just getting started, I would suggest the AVR or arduino platforms.

Our tables are not *yet* an open-source project; we do plan the release, but we need to take care of a few things first. Obviously there's nothing wrong with publishing your different approach to the idea of an interactive table.