Jetson Jetbot

So both of the pi-cams I have are both ver 1.3, and apparently, you need version 2, so, we move on to plan B

And since I don't have a plan B, I'm just going to wing it. Luckily, I have an extra C270, which seems to work just fine

Mounting it, however, on this tiny little frame, is going to be fun

Well, it works... After a fashion. Carrying enough power on a frame this small is an issue, plus the Jetson doesn't seem to like the gamepad I'm trying to use as a joystick. The keyboard controls work. And I need to learn the web interface thing so that I can program the obstacle avoidance. It even has a roaming mode, which, of course, won't work without the obstacle avoidance, but I think that's just a learning curve for the interface. You actually have to teach it what it means to be "blocked" and what it means to be "free", which is cool

I was attempting to test something using ROS the way it was intended, with 2 SBC's and an arduino, but, that got complicated, so I removed parts until I got it to work, and what I got to work was the RPI mounted on a frame with wheels, using the L298N controller. This worked fine, until I tried to add the arduino into the mix, at which point I got confused, and then the Featherwing finally showed up, so I swapped out the RPI in the frame for the Jetson nano so that I could test the Jetbot project, which was already programmed, if you had the right hardware

This is working, except that it appears that the Feathwerwing sucks about 4.5V right off the top just to run it, which meant that the batteries I had been using successfully with the L298N were no longer powerfull enough to run the motors at full speed. I tried mounting all the batteries on the frame, but, it was just too unwieldy. There was just no place to mount all the batteries I needed for both the Jetson and the motors

So,  I decided that I needed a bigger frame to test the Jetbot on, and, since I FINALLY finished a project on my printers, they were now free to use for something else, which is a new frame for the Jetbot. Since my printer isn't actually big enough to print all the parts I need, I'm only going to print the parts that I can't otherwise fabricate. So I'm printing the tank treads and tread mechanisms, then I'll just build the platform out of wood or metal

These parts are pretty big, so, some of them are taking a full day each to print, and others, like the tank treads, well, I need a LOT of them, and due to really good bed adhesion, I'm only printing the links in lots of 3 each, which means that this could take awhile

@spyder

Hi Spyder,

I would ditch the L298N for such a low-power bot as they are very power-thieving. I tend to use them only on motors I am going to overpower. You may try the L9110S, TB6612FNG or MX1508.

Scott

Posted by: @triform

@spyder

Hi Spyder,

I would ditch the L298N for such a low-power bot as they are very power-thieving. I tend to use them only on motors I am going to overpower. You may try the L9110S, TB6612FNG or MX1508.

Scott

 

I didn't have any of those in stock

@spyder

I can send you a few 🙂 

@triform

Thank you. That's extremely kind. But, I only chose that because it was something I already had sitting on a shelf that I could use instantly, plus, Bill already covered the L298N in a video about 2 years ago, so I had a passing familiarity with it

If you think one of those would be a better idea, I'll go ahead and order a few, however, that would also require sketches that I don't currently have

@spyder

Hi. Spyder.

What's the more specs or type you are going to use and how many?  Based on that I can pinpoint a recommendation.

Scott

It depends on which project we're talking about. For the Jetbot, I'm kinda stuck with the controller that Nvidia programmed it for (cuz I'm lame when it comes to programming), although I can change the motors, which I plan to do. I just ordered a couple different models for that one cuz I'm building a new case for it so I will have more room. 

The other one, well, the motors came with the frame, which is 20 years old. They seem to be about 6V motors (markings have long since worn off, but they seem to work fine with 6V). This one doesn't matter which controller I use. This is the one I want to use with arduino and Pi

Here is the motor I'm going to use for the test bed (the blue one)

And here's the new test base unit for the Jetson. Obviously, still a work in progress. I needed to print 34 of those individual tank treads, drill out the supports, file them, etc. That took about a week, and I still haven't finished printing the treads for the other side

The ruler should give you an idea of scale. The reason that the treads look different from the base unit is that I'm using two different filaments on two different printers. One printer is printing the base part, wheels, gears, etc, and the other is doing nothing but tank treads. I've only got 25 printed so far for the other side, and I've still got to make some kind of chassis to connect the two halves. I'm leaning toward sheet metal for that, and I still haven't decided if I want one motor per side, or two. I originally planned for only one, cuz it's just a test bed, but, I did leave room for two per side

Since it's just a test bed, none of the ideas for this thing are set in stone yet

They're all set in... melted plastic ? 

I decided to go with 2 motors per side for a total of 4, and this thing should be capable of holding enough power to run them all pretty easily. I'm not happy with the way that the wheels turn the tracks tho, so I've got some re-engineering to do

Okay ! Making progress here... SLOWLY, but progress nonetheless

I temporarily removed the treads and replaced them with wheels. The treads fit over the wheels for when I want to put them back on, but, I've got the thing up on "jacks" and it pretty much weighs a ton with the treads on it, plus, all I'm doing right now is testing the wheel action

I wanted to make sure all the motors move in the right direction, which I didn't. There's only 3 ways to connect the motors... with left-right correct, with fwd-back correct, and with both left-right AND fwd-back correct

I, of course, got it wrong the first two times. But it's right now (as far as the jetbot notebook software is concerned anyway)

I've started the teleop thingy, and it sorta works. I can't seem to get a picture out of the camera via the notebook, but it works fine in the cheese program that comes with the Ubuntu version of Jetbot software

I ordered the PiCam V2 that it says it wants, but it hasn't showed up yet. I'll worry about that later

When I get to the part of the notebook where it's supposed to move the bot with the on screen buttons, it works fine, but, it's giving me an error when I try to use the gamepad joystick thingy. I looked at this page

https://html5gamepad.com/

Which tells you about your joystick, and it looks like, according to the software, that it controls the motors individually with the left-right controls. So the left knob is for the left motor, and the right knob is for the right motor. Logical I guess, but, if it worked, it seems like a straight line might not be an easy thing to accomplish

I'm not quite sure what the error is since I don't really understand exactly what it's telling me other than that it doesn't work

Here's the control page...

If somebody could help me decipher this it'd be greatly appreciated

Also, I put a 15,000ma battery in it to run the Jetson in low power mode, which works, and I've got some batteries for the motors, so, it's self powered right now, so I guess that's a plus.

Joystick-Teleop control is where I'm stuck right now. Axis 1 and axis 3 is giving me readings, but it's not making the thing move

Help

I think I understand the camera now. The jetbot software is written specifically for the IMX219, so any camera with that chip is gonna work, just not any of the ones I currently have

Still don't have an answer on the joystick yet tho

I got the joystick working ! (yay)

It's digital proportional too, so, less movement on the stick equates to slower speed. And there's enough buttons on the joystick screen that if I knew what i was doing I might be able to add more functions to the robot.

Although, calling it a robot right now is a bit of an exaggeration. It's more of a fancy remote control toy tank at this point

A tank sans tank treads. I'll put them back on when I'm ready tho

But hey. It's one more step 🙂