Here dropbox link are two versions of a connector interfacing board for the FRC robot controller. These are conceptually similar to the Swyft Robotics JCB-0001 “NI roboRIO JST Board” but have been optimized for our own requirements. The designs may be used as-is or as-modified under the terms of the Creative Commons CC-BY-SA-NC license.
The primary objective for both designs was to provide a mechanically secure alternative to the square-pin connectors used on the NI RoboRIO. The “V1” board uses 4.20mm pitch connectors sold by several manufacturers under various brand names, e.g. Molex “Mini-Fit Jr.”. We planned to use this version of the board during off-season competition (BunnyBots) and for advanced software development, so I included connectors for all the analog and digital I/O pins on the MXP connector as well as the primary analog, relay and digital I/O pins around the edge of the RoboRIO. I provided additional four-pin connectors routed to pairs of DIO channels for easy connection of quadrature shaft encoders. I did not, however, include breakouts for any of the RoboRIO PWM channels as our designs are using CAN for all our motor controls.
The second version of the board uses the slightly smaller, but more expensive, 3.81mm “Euroblock” pluggable connectors, again available from several manufacturers. The smaller connectors, along with the ability to stack two three-position connectors in the same space as one six-position connectors, leave enough room to include connectors for all the PWM channels. This is the version of the board I expect will be most useful to other FRC teams.
In order to aid both software development and diagnosis of sensor and actuator wiring problems, I included LED indicators on the DIO and the relay channels. The LEDs on the DIO channels illuminate when the DIO line is pulled LOW by an external sensor (or by a low output from the RoboRIO, but we didn’t use any digital outputs.) Although this may seem “backward,” it’s actually quite convenient because it works with common open-collector or switch-closure-to-ground sensors operating at either 3.3V or 5V and because it means the LEDs are OFF when the sensor is disconnected. The LEDs on the relay channels illuminate when the FWD/REV outputs are driven HIGH by the RoboRIO. Each of the LEDs draws less than 3mA so they should not interfere with sensor or relay operation. OTOH, we haven’t yet verified with FIRST that this is in full compliance with R75, so we plan to construct one of these boards without the LEDs for competition use.
I’ve included the original Proteus Design project files, printable PDFs of the schematics and layout, generated Gerber files for board construction, and parts lists and pick-and-place files for board assembly. You should be able to send the Gerber files to any of the prototype PCB manufacturers and get bare boards back in one to three weeks. You’ll also need a day, or a few days, to hand-solder all the connectors on the board. (Hint: assembly is faster and cheaper if you leave out the LEDS and resistors and install only as many connectors as you really need.)
CSA and mentor,
FRC 1425 Error Code Xero