My First Vex Robot

I’ve added a link to a video. The video is only 5 MB in size and is 2:43 minutes long. The quality is low, so apologies about that.

The assignment was to load materials from point A and transport them to point B. The method of loading and the materials were left up to the students to decide. The robot had to repeat the task three to five times. The robot was based on the Protobot design. I added a scoop to the arm (I need to rebuild it - it started wearing out and not closing completely) which used gears to open and close. The robot used one light sensor and a bumper switch on the front and back.

The basic program flow is as follows:

  1. load scoop (lower arm, open/close scoop, raise arm)
  2. Backup (preset backup - needs to be rewritten - not flexible)
  3. Rotate right and search for sequence of light and dark lines (patterned search until it finds the far black line of the long center path)
  4. Follow line (if hit pure white, then go straight) until bumper switch is hit
  5. Backup (again, not flexible enough, needs rewrite)
  6. Rotate (same as 3)
  7. Follow line until hit bumper.
  8. Repeat 1-7 for three more times.

I had one hiccup when the robot was returning from the second trip, but the rest of the trips went fairly smoothly.

Windows Media Video file

I could have done better on the programming, but had been a little overconfident, and ran short of time. I made some decisions that were not ideal, but worked for the project. I plan to break down this robot and build another design that I had in mind.

The above project was an assignment, and now that the class is over, I can play with it.

Nicely done. Congratulations.

Thanks. I appreciate the kind words. I’m looking forward to working with it more.

Just booted up my PC and checked out the vid.

Awesome robot! My first independent robot with vex was the squarebot, and my first custom just shot rubber bands.

Yours has a scoop, line tracking, and adjustment sensors. I haven’t even built something like that; The best I’ve built was a candle snuffer. Boring, I know.

And the programming didn’t seem rushed, it moved around perfectly.

Mind uploading schematics/a pic for that claw? I’ve been trying to get a working design for one, but all of mine has been hyper slow un-reliable worm gear ones.

Anyways, great job and welcome to the community.

Cool robot. I like how you use the bumper blocks as a backup sensor if you miss the line change.

The grabber claw is a nice design. Can you tell me what you are picking up?


I’ll try to draw up the specs for the scoop this week. It’s far from perfect, and it could stand to be redesigned (or built with tighter specifications), but it worked for the project.

My materials that I was moving were tamarind seeds. I was on a kick for a while eating tamarinds, and I saved all the seeds. All are irregular in shape and are glossy brown.

Wow, impressive! It’s not easy to scoop/carry such small objects without spillage.

BTW, ever try Mangorind? Not peelings, but a blend of mango & tamarind – better than candy!

Mangorind? I’ll have to look out for that. Sweets are my weakness. Now I’m getting a craving for more tamarinds.

One thing that I did to “help” keep the scoop closed was the addition to two magnets. Worked fairly well. If I added a potentiometer, I think that it would work better. I mounted a switch which was flipped by a long bolt sticking out of a shaft collar. As the scoop was degrading in performance, I started having lots of spillage. :frowning:

Here’s some photos. Sorry for the poor quality. I’ll try to explain more later, but I have a major research paper to complete in the next couple of weeks.

You have some very innovative ideas in action. Since we are always thinking competition, I’m always thinking about Vex parts. Which means I’m not always thinking outside the box likey you are. The pen spacers are very good idea.

I’m sitting here looking at one of those giveaway plastic mini-baseball hats they serve ice cream in. It looks like you could split that to make the scoop. The flat bill of the hat would give a flat place to attach the closing gear. You might look at the Dollar Store for plastic containers, you may find one that will make a sturdier scoop.

A pot may help on figuring out when the scoop is closed. Or one of the limit switches (the switch with the long flat metal arm would also work. I’d set it up so that one side would push it towards the center, when it trips the scoop jaws would be in their closed position.

And I can’t help you with Mangorinds. When I want something sweet I just head straight for the chocolate stash.

I agree about using the pot. That would be the first thing that I would change. Being a cheapskate, I didn’t want to order it because shipping was so much. But now, I’ll be ordering more sensors, so the bigger order will offset the shipping costs (in my mind, at least).

As to the scoop, the plastic sheeting worked fine (but excellent idea about those small baseball caps!). I used the softer plastic, because I wanted the scoop to deform a little when it touched the ground. Ideally, it would flatten out a bit against the ground. One of the problems was my misalignment of the paddles. I made an incorrect assumption when I cut the slots. If I recreate it, I’ll make a jig to hold the cogs in place and line up the paddles correctly, so that they close properly with no gaps. The magnets on the scoops worked well. I was quite happy with those.