CrossRoads:
Welcome to the forum.Start by updating your profile so folks can make geographically correct referrals for material - doesn't do you much good to know that everything you need is in a surplus store in California for instance.
Mega has 69 IO pins. Your list doesn't appear to need that many. The touchscreen does use a few. Looking at the pictures it appears that at least 32 pins are not committed at all. If your other components needs I2C or SPI access, you may have to add some jumper wires to bring the two I2C pins and the three SPI pins to an accessible point.
Or make the touchscreen cards the last thing on your stack of parts.Your sketch can include a clock program, may drift a very little bit, you can update it when connected to the PC as suggested.
You can connect to the internet with an Ethernet shield. Probably get the time there too.
You can get Wifi, bluetooth, 315/434 MHz, 2.4GHz, all kinds of ways to connect wireless to your PC.
Thanks, I updated my profile.
I would like some infos about shields. For example with ethernet shield + touchscreen shield, how am I supposed to plug those, if they both need same pins? How arduino can route to the correct shield? I don't understand.
Also, on the "adapter shield" (the thing between the screen shield and the arduino), you see there are pins at the sides, I think I've read that they are unused: are they just used as supports for the weight?
sdturner:
Unless I am missing something, the kit in the link is just a display, not a touchscreen.The simplest wireless link would be a wireless UART or wireless RS232 link. It will look like a serial port on the PC and you can communicate via Serial.read()/Serial.write() on Arduino. It can be done with Bluetooth or WiFi, but it will require a little more knowledge on both ends (Arduino and PC).
Steve
No the screen is touchscreen, they probably forgot to mention it! Look this ebay link (I apologize if I'm not allowed to post ebay links just tell me and I remove) and this library
About wireless (that I prefer over ethernet, for this project), is wireless UART or RS232 bidirectional?