We are trying to find a simple and less expensive substitute for our cRIO for our demo bot, that doesn’t require changing too much wiring or programming. We need to take the cRIO off but want to still be able to use the robot. Unable to find anything in search but may be wording it wrong.
Thanks
Technically the cRIO is still supported as an endpoint for LV and there are some threads about getting it to work with other languages but I can’t speak to those.
AndyMark is selling the Gorgon board:
I haven’t used it and don’t know how well supported it is but it’s been around and I believe you can get some help for it if you need it.
AndyMark also sells the HERO from CTRE (http://www.andymark.com/Hero-Development-Board-p/am-3206.htm). 900 used the HERO to replace the cRIO on our 2014 robot and it’s still going. We wrote a white paper about it. Nothing particularly revolutionary in the paper but the HERO is awesome and we really like it.
If your willing to do a little tinkering in C, the CTRE Hero dev board is looking like a really good option in my opinion, it also has compatible with all the CAN bus stuff FRC uses nowadays. But marshall does know more than I do 
Crios can be had for cheap or free. The problem is the programming languages are not supported any more and it will take a bit of resources figure out how to implement them. The RoboRio is the closest substitute, but has the downside of cost. Anything else will require complete reprogramming. There are a lot of options if you can run everything open loop with PWM outputs to the motors. Some possibilities are Arduino, the NXT that FTC used to use. I have not looked closely at the current FTC solution, but that is a possibility as well. The Hero is good option if you want canbus. Reading enocoders and vision processing add a lot of complication. So the first step is to decide how complex it you robot. If you keep it simple then there are a lot of inexpensive solutions out there.
Having been around FTC a fair bit the last few years, I can’t really recommend their platform as a solution for an FRC-style demo robot. The REV Expansion Hub is an improvement in a lot of ways and does offer six PWM outputs, but the connection to the phone using a USB OTG cable is still a bit fragile for a lot of teams’ liking–and any FRC-scale robot out doing demos on sidewalks is going to see much worse conditions than an FTC robot on foam tile. If you can use the REV Hub Interface Software or some other means to talk to the hub and get around that weak point, then it’s more palatable in my eyes.
I would not invest much time in the NXT/Samantha setup unless the hardware was in-hand and I just wanted a hacking challenge. Both NXT and Samantha are beyond EOL, and most of the resources for setting it up got hosed in the great FIRST website migration a few years back.
Also, nobody brought it up but the Cheap & Dirty setup may also suit your needs depending on what you want to do.
Our team got the Gorgon to work on an old robot. Based on how quickly one of our programmers got it to work, this might be one of the easiest ways to get an FRC robot running.
I’ve always wanted to setup a robot with a plain Arduino with the USB receiver of something like this gamepad plugged into a USB host shield. If we could get an Arduino to play nicely with a USB gamepad, then this would be an easy way to control the robot without the need for a driver station. But we have always run into snags with that before getting distracted with other projects. Gorgon is easier.