Hi, I am making a homemade robot with some frc parts. I have 2 questions what can I use as an alternative to the pdp? My budget is small. Also, how do I put A Victor sp on can with the CTRE CANifier?
Thank you
The hero board can be used as it is as a C# based robot controller or flashed to act as a CAN to USB adapter.
There is also a device called a Canable that can be used for the same task of CAN to USB. Then with a Linux based PC like a Jetson nano, raspberry Pi you can control any CAN 2.0 (TalonSRX, VictorSPX, Pigeon 1.0, older generation not CAN FD) devices with CPP code.
For the PDP specifically you are looking for a fuse board rather than current measuring and the other fancy features of a PDP. I have had good luck with The Chunzehui F-1005 9 Port 40A Connector Power Splitter Distributor Source Strip, 1 Input and 8 Output. https://a.co/d/fxBCUaT
It uses Anderson power poles so should be familiar for many in FRC and it supports changing fuses out as needed. There are larger sizes for more amperage, depends what your homebrew project has for power draw.
CTRE sells the PCB for a PDP without the smarts just for power distribution.
This is unfused so you will need to add fuses to each line as nessecary. This however does distribute power from the battery to the other poles as it says, just no safety built in.
Edit: found a picture of when I did this with a Jetson nano, talon srx, pigeon 1.0, a couple off the shelf window motors with wheels and a basic terminal rail (before we found the nicer one). The encoders are missing but was based around the srx magnetic encoders
Eagle eyed people will also see a REV FTC power switch because that was compatible with the smaller FTC batteries I had at the time for 12v and the regular FRC batteries were much too big for the project.
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For smaller/cheaper power distribution with breaker protection, I would recommend an inexpensive ($10-$20) fuse block used in cars, e.g. https://www.amazon.com/dp/B07W6KBJ8G/
(FRC used these [not this exact one of course] for many years, before introducing the blue PDP in 2009)
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What parts do you have from FRC land? I’ve found that if you don’t need CAN and can stick with PWM, you’ll end up saving a lot of money. The newish Arduino Uno 4 Wifi is super budget friendly and will let you prototype with wifi, LED’s and a lot of other little features making it super versatile for use in multiple different projects.
For reference, when I upgraded my spool robots to have CAN and TalonSRX’s with Encoders, it took a robot of net worth ~$250 to ~$600.
If you need CAN, CTRE is a excellent choice, and the Hero Board made my life infinitely easier with their excellent customer support.
You might consider changing the name of this thread to something like “How to build a custom robot with FRC Parts” as it’s a lot more similar to what you currently are asking.
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I have 2 3 cim ball shifters and I might get victor sp
Victor SP can be driven via PWM on its own. The green and yellow CAN wires become PWM on a TalonSRX or Victor SPX. Not sure which is which but it does work.
If you go the Arduino route treat the signal line as a servo and use the writeMicroSeconds function. 1000 is full reverse, 1500 is stop and 2000 is full fwd. The wiring is covered in the Victor SP manual for standard pwm
Cool cool.
I don’t know what it is for a Victor SP, but I know a Victor SPX and Talon SRX have a continuous current of 60 amps, so you could probably get away with one motor controller per ball shifter using a Y cable at the power output. This is only legal in FRC for bag motors (assuming those rules haven’t changed) but probably will work for your purposes.
You might also like to use a snowblower motor from AndyMark, as shown in @kingc95 robot above. It’s less powerful but already geared to work in certain applications without a gearbox. They are nice for “figuring it out” the first time.
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I will say those motors are “fun” to work on the mounting for. You end up with parts sticking under in many orientations so make sure to get at least 5 inch wheels if you do go that route to get clearance.
Ok so will the cima and motor controllers draw more than 30 amps per group because the fuse blocks I am looking at max out at 30 per channel.
FRC rules spec those for 40A breakers, per motor. When I or my coworkers have used them for work stuff we’ve always tried to make sure the power supply can hit 60A or more in case of over-amp, and we’re tending to run one or maybe two motors per supply.
You’re running 6 CIMs, in two groups of 3. That means you’ll need 6 channels each able to hit at least 40A. (Note that in practice, that doesn’t mean they’ll all pull 40A, particularly when grouped.)
Are there any Raspberry Pi CAN FD devices compatible with CTRE CAN FD?
I found a couple devices that are CAN FD compatible, but I don’t know enough about the CAN FD standard to know if they’re all inter-compatible. Some of the Pi adapters talk about max data rates of 5 or 8 Mbps, and CTRE advertises 10 Mbps so that has me on alert that maybe not all CAN FD busses are the same.
Examples products:
and
I started looking at these as a possible way to build a “black box” to log all CAN and Ethernet traffic on a robot. Now I’m thinking you could directly connect an IMU like the Pigeon 2.0 directly to a Co-processor and do localization completely offline from the RoboRIO.