paper: The HERO for FRC

frc900
hero

#1

Thread created automatically to discuss a document in CD-Media.

The HERO for FRC
by: marshall

Migrating the 2014 Zebracorn Robot from the cRIO Platform to the CTRE HERO

White paper describing our process for migrating the 2014 Zebracorn Robot from the cRIO Platform to the CTRE HERO.

TheHEROforFRC.pdf (3.65 MB)


#2

We’re happy to answer questions about our experiences using the HERO from CTRE! It’s been a great project to work on for us and we’re thrilled to have had CTRE sponsor our work on this.

If you’re looking for an alternative control system for a robot then we can highly recommend the HERO. It’s a great platform.


#3

Thanks! This is timely, as we’re deciding how to keep our demo robots running without forking out $500 for another roborio.


#4

So what advantages does the HERO offer over the cRIO? Is this just a cheaper alternative for non-competition bots or is this a possible replacement for the cRIO?

Also, this is great work from what I can tell. (Though my extent of electrical and programming knowledge is that it’s basically all sorcery, so who knows?)


#5

Thanks! We have been trying to get out there for teams exactly for that reason. It’s a great choice for that… at least it was for us.

  • It’s cheaper.
  • It’s supported now (not that the cRIO isn’t but it wasn’t for us… the 2CAN LabVIEW drivers/libraries for the cRIO are kinda busted now).
  • It’s cheaper.
  • It doesn’t require a driver station to run.
  • It’s a lot simpler to wire up.
  • It allows you to use Talon SRXs with it via CAN.
  • It’s cheaper.

Yeah, there is a lot to like. :slight_smile:


#6

I’m noticing a theme…

In all seriousness, that is good to know. My team has only disassembled our 2014 robot and we built a demo bot for kids out of the chassis, but we’ve been stripping the control systems off of all but the demo bot and this year’s, so we could use some cheap control systems.

We would have no need for CAN capabilities, so could the price point be dropped even further by using Sparks?


#7

The HERO does provide PWM outputs but it’s not something we’ve tested. If you go that route though, you’ll need to breakout the 10pin .05" headers to PWM connections.

Something like this should work for breaking out the PWM connectors: http://core-electronics.com.au/servo-motor-expansion-module-gadgeteer-compatible.html


#8

Thank you for that; I’ll let them know that option exists.


#9

Have a wiring diagram to share, and a priced BOM?
I have two robots that I would also like to keep running, I have one already working with the ardunio and 221 hardware.

Can you talk about what the srx breakout was used for?


#10

Wiring is dead simple, it’s 12V and CAN. I don’t have a diagram but maybe I can bribe a student into making one. It really isn’t hard though.

The breakouts were used to attach the encoders on the drivetrain to the Talon SRXs. We plan on testing out motion magic and motion profiling on this robot within the next few months so we’ll need the encoders. We also needed them to attach to the limit switches to prevent our mechanism from breaking.

BOM:

1x HERO - $60
6x Talon SRX - $90x6 = $540
4x Encoder Breakouts - $10x4 = $40
Total Cost = $640

That might seem like a lot if you are buying all of the parts new but I suspect most teams won’t be and instead might be looking to keep their stronghold robot online and working which might be using CAN today. The bulk of the cost is from the Talon SRXs and if you don’t need to purchase those or plan on purchasing new ones then it’s not that bad.