CHAPTER 9Two-Wire Powered Sensors
The original LEGO MINDSTORMS brick, the RCX, used a two-wire powered sensor interface. The NXT has a backward compatibility mode with the old RCX sensors, and that mode offers some advantages for homebrew sensors that need higher voltages than the 4.3V supply described in Chapter 8. It's a natural choice for sensors that need to take full advantage of the 5V analog-to-digital conversion. Conveniently, the two wires are the same two wires you already used for passive sensors: the white and black wires in the NXT cable, or pins 1 and 2 on the port connector.
Signals
Power and sensor readings are combined on two wires by splitting the functions in time. First the sensor signal is read, with exactly the same method ...
Get Extreme NXT: Extending the LEGO MINDSTORMS NXT to the Next Level now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
