LEGO mindstorms and FPGA

Why? Do you need microsecond level timing on some control loop?

In general, if you can do the problem in software, it's better to use a uP rather than a FPGA. The developement software is more user friendly. That makes it much faster to try a new idea.

What about implementing an hitachi h8 mcu in an fpga? And attach exactly the same external components as in the rcx itself? then you have a "custom" rcx that you can add advanced hardware into. You can create a second microcontroller,statemachine whatever with a number of io/s and you can create som sort of software using the IR send / recv command in the h8 to do communication with second mcu? So that the ir port of the h8 is mapped to both IR and internal mcu-2. Create a protocoll so that you can sort out data packets to / from second mcu or packets that acutally come over IR.

Thomas

unsolicited

addresses.

Not that I've seen.

Some verilog code for servos etc here

Alex

by

Mean reason: Just for fun ;-) Secondary reason: Get a testbed for some control programming in Java on my Java processor.

I will use the FPGA only for interfaces to the sensor (sigma-delta ADC) and the motor (PWM output with readback of voltage levels during the off time). I will put the schematics for the sensor and motor interface with some VHDL code on a webpage when I got it work.

Martin

--

---------------------------------------------- JOP - a Java Processor core for FPGAs:

It depends how far you want to go w/ your robot. One of the LEGO extension sets includes a Logitech USB Camera. Unfortunately, the camera is connected to the PC via the USB cable (limiting the movemens of your robot), then few pieces of information are sent back to the RCX for robot control.

We can't call really it an autonomous agent, can't we? It would be a better idea to handle the camera directly from the robot itself. You would need a processor to handle the USB protocol stack, but an FPGA would be nice to compute in real-time the images that you capture in order to improve the robot capability to react to what it sees.

In such a case, the processor would indeed offer more flexibility but wouldn't be able to compute the huge amount of data so effiently. Therefore, an approach incl. a processor + an FPGA would be nice.

Eric

camera

Yes a camera module on the robot would be nice. I have a simple digital module (M4088 with OmniVision's image sensor OV5017) that I wanted to connect to the FPGA some time ago. I will probably do it now for the LEGO robot ;-)

The camera module I mentioned is far simpler to connect. You don't need an USB stack, just digital signals.

As processor I will use my Java processor inside the FPGA, but the NIOS would also be fine.

Martin

I would suggest running it past the comp.robotics.misc group

I know a few that are running robots with FPGAs but I don't keep track on the LEGO stuff.

Eric, camera wise, you may look at the mindstorm Vision Command. It looks somewhat new on Lego website so I am wondering whether it is on sell already...

kelvin

Martin, are you willing to share your Java processor codes? Got any website on that?

Kelvin

Kelvin,

do you mean the processor itself or the Java code for the Lego robots? The Java processor is available in VHDL at:

For the robot stuff I just started to build the interface to the sensors. I have only a three liner in Java to read out the values, but I will put the schematics and VHDL source on a webpage.

Martin

website

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NIOS

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The LEGO sensor interface to the FPGA with a sigma-delta ADC is completed. I've set up a web page with the schematic and the VHDL code:

The motor control, camera input and hopefully a nice roboter example will follow.

Comments and suggestions on this solution are welcome ;-)

Martin