Week 1: System Overview - aka: It Begins

Professor Anderson advised that I begin my research with some investigation of what I'll be working with. I agree that 9 out of 10 times it is in your interests to know what's going on. And so I began with a systems overview, and basic requirements analysis.

Now the overall goal can be stated pretty simply: Make the Arduino talk with the NXT.

Fig 1. Eventually, the Arduino will be used to interface with custom sensor implementations, presumably breadboarded or developed as part of the new class.

Since whatever I decide to work with will revolve around what the NXT has to offer, I'll begin with some basic analysis of the NXT's hardware. Some cursory investigation yielded that the NXT is equipped with an ARM7 AT91SAM75256 embedded processor. The use of an ARM7 processor indicates that the NXT platform is deceptively robust, and among other things has native hardware support for communication options such as UART, USART, and SPI. The NXT itself is connected to a computer a la USB 2.0 cable, and the newer revisions (with which I am presumably working) appear to have bluetooth, though further investigation seems to indicate this is for remote programming and control of the NXT instead of for general use by the user program.

As far as embedded platforms go, the Arduino is fairly versatile. Any of the above communication options (UART/USART/SPI/BT) are viable to implement with the proper time and, in bluetooth's case, hardware. However all of these are relatively complex for what we need, and thus by the KISS principle I'm going to turn to the obvious low-hanging fruit: The RJ12 jacks already used by the NXT for sensor communication.

Fig 2. The four RJ12 sensor ports in all their glory.