Lego RCX + BS ??

CircuitMage

So, I ended up winning that Lego RIS kit at the Goodwill auction for $55. Some guy bid me up over $50!

WOW. These kits are amazing fun. Very simple. In 1 week I completed 4 projects. Now working on my 3rd improvement on a light theremin project. I would highly recommend these kits if you can find one, though on Ebay they still go over $100. The GUI programming interface is sweet. Very well made SW. I got it running with the serial port IR tower on my Dell laptop. Very Sweeeet.

A quick search here yielded nothing on Lego RCX, but google searches point to a few sources. I also found a book on Ebay for $5 on interfacing the RCX, that should be here soon, but I've already found several web pages on homebrew sensors.

Any other sources here for BS interfacing/ideas? I've already found ideas for opening more I/O ports using the BS. Very nice. I guess that's the basic idea anyway, but I would like to use the BS with the RCX block for other capabilities.

Duane Degn

I have a couple of RCX sets. IIRC, the inputs are analog so the light sensor outputs a voltage that the RCX translates into a light intensity. So if you could get your BS to communicate with the RCX, you could use it for analog inputs.

I have no idea what the IR communication protocol is like with those. If the $5 eBay book has the protocol, you should be able to use a IR LED to program the RCX from a BS.

I'd think the RCX would be useful as a motor controller (IIRC it can control three motors). You might be able to use it's LCD screen and as I mentioned, you could use it to read analog inputs. You might be able to use the RCX's buttons too.

I'd think you could use the RCX's batteries to power the BS. It might take a bit of hacking to add an exteral connector. The version 1 RCXs have a barrel jack to use with an external power supply. I bet it has a protection diode you'd need to remove in order to use this connector as a power supply for your Stamp. The latter versions of the RCXs didn't have this connection. which I thought was a really bad change since it made the RCX a battery power only device.

I hope you let us know how you end up using it.

CircuitMage

Duane Degn wrote: »

I have a couple of RCX sets. IIRC, the inputs are analog so the light sensor outputs a voltage that the RCX translates into a light intensity. So if you could get your BS to communicate with the RCX, you could use it for analog inputs.

I have no idea what the IR communication protocol is like with those. If the $5 eBay book has the protocol, you should be able to use a IR LED to program the RCX from a BS.

I'd think the RCX would be useful as a motor controller (IIRC it can control three motors). You might be able to use it's LCD screen and as I mentioned, you could use it to read analog inputs. You might be able to use the RCX's buttons too.

I'd think you could use the RCX's batteries to power the BS. It might take a bit of hacking to add an exteral connector. The version 1 RCXs have a barrel jack to use with an external power supply. I bet it has a protection diode you'd need to remove in order to use this connector as a power supply for your Stamp. The latter versions of the RCXs didn't have this connection. which I thought was a really bad change since it made the RCX a battery power only device.

I hope you let us know how you end up using it.

All good stuff. Yes, the inputs are analog, lots of info on the net for interfacing and customs jobs. I have not taken time to go through all the BS apps though. I think the IR comm is documented and available.

Funny how you are thinking of slaving the RCX with a BS, whereas I was thinking of slaving the BS, I need to consider both options. I'm already seeing limitations on the RCX brick though (ex. sounds are limited to 0.1 s duration, not shorter, and some very lengthy decision loops (~25 decisions) start to lag), so it may function better as a slave compared to a BS. I have seen others use the RCX as a slave controller.

I picked up an add-on kit on Ebay, that has the remote also, which lets you control the brick functions.

I have a 1.0 Brick from the 1.5 kit, so it does not have the jack. , but I was thinking about shared power too.

spiked

I'm not sure that my use of the letters BS means the same as you but take a look at http://lejos.sourceforge.net/ for some serious access to an RCX that may or may not be helpful. Other than that, what does your BS stand for? :P

CircuitMage

Yeah, I've seen that the library has been ported to like 20 different programming languages. I really like the simplicity of the GUI programming, and am not sure what going to another language will open up for me at this time. VB seems to be popular too.

BS= Basic Stamp

spiked

"20 different programming languages" - got any references? I just reluctantly accepted Java as my only choice, as I find no 'robotics' library as advanced, other than possibly ROS. ROS uses C/C++ but has typical open source problems, you spend more time tinkering than doing. LeJOS has pre-built Subsumption, navigation (pose and mapping), PID as well as broad sensor support. - So if your robotics ventures desire to go there, it can save quite a bit of time by avoiding the low level raise pin 3 high kind of code (which maybe you prefer, to each his own). Thanks for explaining BS, I read here a lot because I was interested to see if/when Eddie went anywhere. I do not have any real parallax experience.

M

CircuitMage

http://en.wikipedia.org/wiki/Lego_Mindstorms#RCX

I agree that pin code can be tiresome, but useful if debug/design is needed. For simple routines such as the RCX can handle, it's more fun to build/program/run over and over again. Also, I am enjoying seeing what this little board can do so I am doing things like exceeding the variable limitation with custom counter routines.

spiked

ah, i thought you meant LeJOS ported to other languages. Actually I don't think any of the languages they listed are ports, just different projects that run on/with the legos. I have not done pin code in many many years, and do not plan to. I've never had or used an RCX, just the newer NXTs. No pin code on it, unless you get down to to replacing whats running on the unit (as the LeJOS team did).