Quick microcontroller question

Allrighty, so I’ve got this side project for my team where I have to build a robot arm to perform several tasks like picking up objects, scoring them, etc. BUT I can only use a set number of frequencies for the transmitter and I know that the Rx1 and Rx2 ports on the vex-net cortex are withing those requirements (75MHz).

The question is this:

I know how to attach and use the older style radio crystals because I used them in elevation, but I’m unsure as to how this would work with the joystick. Can I use a newer joystick or do I have to revert to one of the original ones? AND if I do use an old joystick, what do I have to do to get it working? I’m assuming that it’ll transmit to the receiver if they have the same crystal number, but do I have to do any programming with it? (if I recall correctly, the programming cables went straight to the PIC in 2008-2009 and had little do do with the joystick). I know it’s not a common question, but any input on how to adapt the cortex to use its Rx1/ Rx2 ports is much appreciated.

The Rx1 and Rx2 ports on the cortex were designed to take the 6 channel pwm signal from the RF receiver, however, as far as I know (never having tried to use them) they are not supported anymore. It took me a while to find this (wish we had better forum search tools) but I remembered a thread from a while back that discussed it.


That was almost two years ago so who knows what works now. I don’t have the necessary gear to test this, MarkO or Quazar might.

To use the old style rf control system there was a VEXnet upgrade, that added WiFI capability to the joystick.

What’s wrong with using the normal VEXnet system?

I’m not positive but will test it when i’m at school tomorrow.

It’s a requirement for a science competition, just something on the side I was working on. There were only certain allowed frequencies for it. I don’t have the list in front of me, but I was curious about what would work. Do the vexnet keys have a certain frequency (I don’t know much about the system and I couldn’t find it in the product description)

thanks for the thread, it helps a lot!

VEXnet keys are 802.11g WiFi, which is 2.4 ghz.

I tried top use a crystal with a cortex today and couldn’t get it to work. I believe it is no longer supported because the project type says (wify) after it so that makes me think that it is not supported. You might be able to if you can get your hands on an older version of the software.

so in short it is not too easy to do. ( from what I saw)

Aha! 2.4 Ghz is one of the acceptable frequencies, thank you very much!