Robomo Club Robot Project


#41

Allowing for switching back and forth between wired and wireless sounds like a good idea. You can probably do that with just a switch, if it is able to handle the current.


#42

After looking at available switches, I agree that relays are probably the way to go.


#43

Regarding motor controllers, looks like the Sabertooth 2x32A controller has a “User Mode” which could allow for combined RC and on board computer control (manual: https://www.dimensionengineering.com/datasheets/Sabertooth2x32.pdf). This feature doesn’t seem to be in the Sabertooth 2x60A model (https://www.dimensionengineering.com/datasheets/Sabertooth2x60.pdf).

The Roboclaw 2x60A (http://downloads.ionmc.com/docs/roboclaw_user_manual.pdf) does allow combined USB and packet serial control - so we could read RC signals on an arduino and then send packet serial to the motor controller. If we really needed 60A per side, this might be a way to go.

/K


#44

We came to the conclusion that since the breaker is 30 amps. The 2x32 should be great.

I’m looking at the Flysky i6 for a remote. Although I don’t know if that’s the best choice.


#45

The parts are on order for the motor controller and remite. So I posted a meetup for next Friday. They should arrive by then.


#46

Weird. I didn’t get the Meetup notice
/K


#47

Got the Meetup notice today /K


#48

FYI. The last of the parts came in today. So everything is on scheduled.


#49

Rather than try and adjust the stand at home, then checking it tonight, I’m bringing a bunch of parts with me tonight so we can just get it right.
/K


#50

Made it over to Arch Reactor today. Got the stand built. Also charged the battery while building.
/K

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#51

That looks awesome! It’s going to make programming the motor control so much easier.

I’m planning on going up there after Saturdays meeting to install the controller and setup the remote control.


#52

Do we need anything (tools, box, components, etc.) to install the controller?


#53

We are making good progress. The motor controller is tuned and working well. The wiring for the charger is started and should be simple to finish. Soon we can start adding the raspberry pi.
One issue that hasn’t been solved is the wheel odometers. There is no direct access to a motor shaft to attach encoders to. We could try magnets on the back of the wheels and mount some reader behind them. It would have to be well made and placed to get consistent odometry. Not something I could do.
Any ideas?


#54

I’ll be out of town this weekend, so I won’t be able to work on the robot on Saturday. Odometry sounds reasonable - I don’t have any experience with it. /K


#55

PROJECT UPDATE:

Craig started on the wheel encoders. He’s going to CAD up a drawing for a inside wheel hub attachment. First trying hall effect sensors.

I started on the manual override and controlling the robot with python. Controlling the robot with the computer is OK. Manual override is going to take a little thought though. It’s hard to detect if the remote is in use or not just by reading RC signals. We may need to use a third channel to signal the override condition.


#56

You can set up a Sabertooth motor drive to use R/C signals, and have an R/C receiver, so that the robot can be controlled with an R/C transmitter,

Then you only need to switch the 2 servo signal wires (left & right) with a DPDT switch ( or relay) to connect the sabertooth board to a “servo controller” board (pololu) - connected to a laptop USB port.

This way, you can switch between computer control and manual R/C.


#57

What ever happened to the club robot project?


#58

Mostly Covid-19. It’s been hard to meetup as a group. If anyone wants to move the project forward they definitely should.