Robomo Club Robot Project


#8

OK. My plan is to get a base by Saturday. I would like to start working on this after the meeting at Archreactor. If there are no better ideas I will get the first sub $200 one I can find on Craigslist.

Any suggestions on a motor controller?


#9

I would expect you can make use of the driver already integrated into the scooter. Craig mentioned an option of using an arduino to emulate joystick output, which would probably be worst case scenario if there was not a more direct solution easily determined, but also totally acceptable as far as I am concerned. It could also become a task to cover in the monthly meeting.


#10

It looks like a lot of the 6 wheelers (4 casters and 2 drive wheels) can have some of the casters easily removed if terrain is flat and loads are simple.


#11

If possible, it’d be nice to take measurements from the joystick and other parts to see what voltage is required to operate the original motor driver. I do have a power supply that we could use for testing but not driving any more than a few amps. Let me know if I need to bring it.


#12

I bought the scooter. So it’s a done deal. I’m bringing it Saturday and will need some help to get it out of my car.


#13

Cool! I will try to give you a call on the way to the meeting Saturday. If all goes well I will get there in time to help you unload it.


#14

I posted a meetup for going to Archreactor after the morning meeting. I’m planning on going there Saturday. I may need to make sure Keith or Craig will be able to let us in. I hopefully didn’t jump the gun a little on this but I wanted to get things rolling. I applied for membership also but I don’t think it will go through by Saturday.

@MarkM Thanks for the help. I don’t know if we should bring it in for the morning meeting or not. We’ll need to unload it at Archreactor though.


#15

Yes, it can
/K


#16

So far so good. Looks like the batteries might be OK. Craig is taking them home to charge and test. Mark tested the charger and it is definitely bad. We’ll need to replace that. Kieth is building a stand so we can test the motors without having the base drive off. Pretty good progress for day one.

wheelchar_taken_apart


#17

Just got the new charger in.


#18

Great to hear we have a charger now!

On a somewhat related note… Here is a link to an RC car running a track using a camera and Jetson TX2.


#19

Looks like the batteries are dead. :cry:
I’m thinking of getting these https://www.amazon.com/Battery-Scooter-Mobility-Electric-Wheelchair/dp/B07VFT6BQT/ref=sr_1_1?crid=Y2VW1SKDB0M9&keywords=jazzy+select+6+battery&qid=1571015528&sprefix=jazzy+selec%2Caps%2C172&sr=8-1

It might be best to test the motors first. I have a couple of 12AH 12V lead acid batteries. Would those move the wheels?


#20

Your smaller batteries would be fine for testing. Because we don’t have a 300 lb person in the chair they might also work for the robot. But the bigger battery will last longer once we put other electronic loads on it. I don’t think it would hurt to try them out and see how long we last.

How many amps is your charger rated for?


#21

The charger is 24v 3A

I’m planning on going up there Tuesday night just to test the motors.


#22

Before you go ordering, it may be good to look into Lithium Iron Phosphate Batteries (LiFePo4). Higher capacity, longer run, significantly better number of cycles, but of coarse, more expensive and a bit more effort to find.

A quick google search came up with some details here:


#23

I think the AGM batteries will be great. The LiFe batteries are better but might be Overkill. The max range is 15 miles already. We don’t want to be showy.


#24

The robot moves! The charger is working as well. I have a video but can’t upload it here. Now I’m looking at the controller.


#25

It’s got a 10k pot for speed control. There are 3 wires from the board going to the base. Power, ground and signal. 8 wires from the joystick into the PCB.


#26

If anyone works on the robot. The brakes must be engaged to control the robot.
I am leaving the smaller lead acid batteries in the base for testing.


#27

How should we interface with the base? Emulate the joystick? or Send signals through the same lines that the joystick controller uses?
I probably should have looked inside the motor controller case. Maybe it’s a known controller with an established serial protocol.