Hey, We are trying to build a t-shirt shooting robot for our school, but buying a C-rio is out of the schools budget. Any cheaper alternatives that you guys would recommend?
Go ahead and use your current cRio for it - you’ll be getting a whole new control system with the RoboRio in the Kit of Parts next year!
We would like to keep the 2014 robot operational, and a new crio isnt in our budget.
The RobotOpen control system from Team 221 Robotic Systems was designed as an alternative FRC robot controller. The system is Arduino-based, and is available as either a set of Arduino shields or a standalone unit. I don’t have any experience using it, but when I looked into it a while ago it seemed interesting.
What are you trying to do with the T-shirt shooter? If you provide some specs we may be able to offer better suggestions.
If all you need is basic control then an RC setup may be all you need. Something like the AM Cheap & Dirty control system.
The Sasquatch Robot Controller or RobotOpen from Team221 will give you more control.
A lot of teams use a VEX cortex to replace their cRIO on old robots.
There are also some much cheaper custom options if you only need a few controls.
I think they understand that. They just don’t want to take their cRIO off their 2014 robot, so they can still use it for demos and things along with their new T-shirt shooting robot.
Basically, we need to drive, move the launcher up and down, activate a compressor, and activate the solenoid to launch the shirt.
What 3946 did was use an Arduino and two XBees to make a remote control T-shirt launcher.
All the code for the Arduino (and I believe the Firmware for the XBees) is avalible on our github: https://github.com/frc3946/MobileAirCannon
What we did was have the XBee standalone in the controller, using its dedicated IO lines as inputs. Then we had the XBee on the Arduino sending that data from the Controller to the Arduino via Serial. Then I made some breakout boards for PWM (S + -) and Relay (A B -) ports.
Here is the hardware we used:
Arduino Leonardo (an Uno or Mega would work just as well): https://www.sparkfun.com/products/11286
2x XBee Pro S1 https://www.sparkfun.com/products/8742
Arduino XBee Shield: https://www.sparkfun.com/products/12847
XBee Explorer USB (For Programming XBees): https://www.sparkfun.com/products/11812
XBee Explorer Regulated (For use in Controller up to 12volts): https://www.sparkfun.com/products/11373
The rest are just buttons, joysticks, battery holders, and switches to make the controller, and some perfboard and headers for the additional breakout headers.
I’m not sure how your system will work, but if you’re using Spike relays, the RobotOpen cannot drive the Relay ports on the sidecar, and driving them directly off the Arduino is iffy in terms of currrent draw (and a pain to wire). It worked great for us on a motors-only robot, but it didn’t work on a robot with solenoids and relays.