RC Train controlled from RCX

[AlexC]

Sorry if this question already been asked, but can't find any answers.

I have an oil RCX brick as well as 7938 RC passenger train set. I know that new NXT brick with additional HiTechnic IR sensor can control the RC train, but wonder whether old RCX can do the same job?

Thanks in advanced,

Alex

[JopieK]

It should be possible. We use Arduino at my school to control the RC train, using just a simple IR LED. I think the RCX IR sender is using a different frequency but apart from that it should be doable.

[Burf2000]

Once I get my RC train, I will give this a go!

[teflon]

@AlexC

I've seen and tested Bob Koyima's solution (see bottom of his page). It worked on PF cars so it should work on trains. As far as I can understand those programs, it enables different type of signal sending (PWM etc.), however I am too clumsy to use it for trains.

If you use this, please report here. I am keeping my fingers crossed.

[Toastie]

I have an oil RCX brick as well as 7938 RC passenger train set. I know that new NXT brick with additional HiTechnic IR sensor can control the RC train, but wonder whether old RCX can do the same job?

Hi Alex,

what Bob has done is replacing the firmware of the RCX brick with his custom code. Usually this means that the RCX forgets everything it could do before (i.e., store/execute LEGO byte codes) - with the new firmware, it now can perform specific but more demanding tasks. I take it from the readme in Bob's zip file that this is the case here as well: With the new firmware, the RCX reads the input from two rotation sensors and sends out the matching PF IR code. Channel switching is also possible by pressing the view/prgm buttons. But that's it then, the RCX can only do that.

This is very, very exciting work, however at the expense of RCX "functionality". Also, this approach is somewhat costly, if you don't have the rotation sensors yet.

The bit protocol for the RC train is again different form the PF protocol. The Mindstorms, PF, and RC IR bit protocols are transported on a 38 kHz carrier, but the bit stream is different in each case. Custom in case of PF and RC and "plain vanilla serial XY00 baud" in case of RCX/SCOUT/Spybotics. With the standard firmware (from TLC) or even with the enhanced RobotC firmware (V 2.03) the RCX cannot generate the IR bit stream required for PF and/or RC.

I guess you have to find a guru that has the capabilities if writing RCX firmware. Bob knows how to do this - he has done for PF. I have done some measurements on the RC bit stream - seems to be very similar to PF but with different timing.

Best regards,

Thorsten

[AlexC]

Thorsten,

Thank you for detailed answer. It looks like that amount of work required to connect RC IR to RCX is very big. Probably I will connect RC IR and RCX through NXT.

Best regards,

Alex