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Comment by andyjohnson0 | Hacker News Reader

Having played around a bit with the original 1998 Mindstorms hardware, I found that the main factor restricting what I could build was the limit of three input and three output ports. Its a bit disappointing to see that the EV3 has added only one more input and one output port.

If Lego had made the physical connectors smaller then I don't see why eight or more sensor inputs couldn't have been allowed. I appreciate that outputs are limited by the on-board power, though.

Still, this looks very tempting.

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The Sensor Multiplexer solves the too-few-ports problem, though it comes with its own sizeable battery pack.

http://www.legoeducation.us/eng/product/hitechnic_sensor_mul...

Didn't know they made these.

I remember building a mux for touch sensors with some resistors and reading it as a light sensor.

A lot of that I think is to keep the complexity of a single unit fairly low. On the older models, you could set up IR communication without too much hassle, and it looks like these new ones can speak over bluetooth and wifi. I'm not sure if they support it out of the box, but I'll bet an API is forthcoming for microsoft's robotics studio or similar, and will make coordinating multiple units a bit simpler.

There is actually an arduino shield that let you integrate arduino with the Lego microcontroller, so you can expand the number of inputs and outputs, though this is mostly a transition from lego to arduino, because at that point, you better off doing everything through an arduino (except that you get to use your lego motors and sensors with it this way). Here is a book that teaches about how to do it and talks more about the arduino shield:

http://shop.oreilly.com/product/0636920024316.do

I don't think they added any sensor ports - still just the four. But now it comes with a gyro sensor built into the brick.

The 4th motor port is huge for some things. It was almost impossible to build a holonomic drive with only 3 motor ports. Now you can have two drive motors and two for manipulators, so you can have a simple articulated arm with a motorized grabber. But I'd sure love to have six of each port.

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