Well, I went out and bought a Kit.

I built the basic square bot as per the instructions. It seems that a couple of steps were missing. Easy enough to figure out if you had experience, but not so obvious to a novice.

The big ones are:

1) Too much slop in the drive train. You need to add a couple of washers so the gears don't walk back and forth on the shafts.

2. The center drive gear is just a fraction smaller than the wheel diameter. The robot will run on short nap carpet, but leave nice track marks. it would get tangled in a shag rug. Also the gears will tend to pick up dust and dirt easily, so I'd never want to lubricate them. The default wheels should be about 3/8" bigger.

3. If you build the robot as shown the wheels will fall off.


Some minor pet peeves:

4. I can't figure out the antenna holder. The parts I got don't match the diagrams, and don't appear to work as designed.

5. All the screws and nuts come in plastic bags with a number on them, but there is no reference to that number in the documentation. Instead of putting 1, 2, 3 doesn't it make more sense to put 8-3/8" 6-3/4" on the bags?



Except for these minor 'nits' the kit and documentation are pretty well designed. But what I am interested in is taking the control system and using it on a full size robot. I got a bunch of globe motors and Victor 833s gathering dust. Robocup Rescue Bot - here I come! This is really important, because most wireless cameras interfere with the 900 MHz garbage band radio frequency used by FRC.

Hey Joe, How come you get to play this stuff early!

[Adam Y.]

4. I can't figure out the antenna holder. The parts I got don't match the diagrams, and don't appear to work as designed.

Take the long plastic tube and thread the antenna through it. After that take the antenna and slip it through the object with only one screw hole. It should have enough room for the antena to fit through.

5. All the screws and nuts come in plastic bags with a number on them, but there is no reference to that number in the documentation. Instead of putting 1, 2, 3 doesn't it make more sense to put 8-3/8" 6-3/4" on the bags?

I didn't find that big of a deal. The small screws only fit into the spacers while the larger screws only fit onto the nuts. The pathetic fact is that for the life of me I cannot get the default drivetrain to tip over. No matter what it always pops a wheelie but it just will not tip over.

[team222badbrad]

I personally do not have a Vex kit, but I know with the Radio Control stuff I have, I usually have to put Vaseline or other slimy stuff on the antenna wire to get it through the antenna tube.

Just thought I would throw this little tip out there in case someone was struggling with this.

[tacman1123]

Originally Posted by Dr.Bot

3. If you build the robot as shown the wheels will fall off.


4. I can't figure out the antenna holder. The parts I got don't match the diagrams, and don't appear to work as designed.

5. All the screws and nuts come in plastic bags with a number on them, but there is no reference to that number in the documentation. Instead of putting 1, 2, 3 doesn't it make more sense to put 8-3/8" 6-3/4" on the bags?

Although you posted this a year ago, I echo these concerns, and found the exact same situation. The bag labelling is particularly dumb, it would be trivial to either label the bags with the sizes or at a minimum provide some sort of description in the documentation.

The wheels falling off is stupid, too -- they need one more instruction to add collars.

My biggest complaint, having spent several hours with the hardware now, is that unlike the Mindstorm kit, which you can try new things very quickly, it's really somewhat slow to just "try this" or "try that". You point out the gear size problem. Suppose you wanted to try a different ratio, see how it affected speed and accelleration (and move it higher from the floor)? You practically have to disassemble the entire squarebot to change one gear!

If the vision of FIRST is realized, that kids start out in elementary schools using Mindstorm then "move up" to Vex, I think the kids are going to be somewhat suprised how how many more limitations there are in Vex. No worm gear, very few angle brackets to allow you to attach parts and motors in ways that feel intuitive but are difficult to do.

We'll see what VexLabs comes up with now that Vex under US FIRST rather than Radio Shack, but I hope they put some resources into general improvements to give the Vex some real flexibility. I'm a big believer that high school students should be using the Vex a lot more before diving into the FRC.

Tac

[GeorgeTheEng]

Originally Posted by tacman1123

We'll see what VexLabs comes up with now that Vex under US FIRST rather than Radio Shack, but I hope they put some resources into general improvements to give the Vex some real flexibility. I'm a big believer that high school students should be using the Vex a lot more before diving into the FRC.

Tac

Just something quick that I feel must be pointed, if only for clarity. FIRST itself has nothing directly to do with manufacturing and distribution of kits. VEX has gone from RadioShack to Innovation FIRST (aka IFI) which is a completely independent company.

That being said though, I think there is a lot of hope that IFI will be able to innovate more with VEX that RadioShack ever seemed to want to do.

[gblake]

Originally Posted by tacman1123

My biggest complaint, having spent several hours with the hardware now, is that unlike the Mindstorm kit, which you can try new things very quickly, it's really somewhat slow to just "try this" or "try that". You point out the gear size problem. Suppose you wanted to try a different ratio, see how it affected speed and accelleration (and move it higher from the floor)? You practically have to disassemble the entire squarebot to change one gear!

Tac

Tac

If you think about it, the tedium of (dis)assembling a design a zillion times as you iteratively test and improve it is exactly part of educating a MindStorm user about what they face in an FRC robot. Those FRC big boys rarely pop together/apart like LEGO blocks.

That you don't have to cut, bend, weld, solder, etc. when rearranging Vex parts is still a blessing compared to how I presume many FRC bots get revised.

So.... Maybe the Vex kits are "just right" for helping students make the leap from LEGOs to FRC bots.

On the other hand - "Maybe not." and "Yes - I agree." Building the same basic wheel design over and over and over again, is getting wearisome at my house too. There are a few parts and subassembly patterns that need to be supplied as COTS out-of-the-box parts.

Blake

[Lil' Lavery]

Echoing an eariler post, FIRST does not create the Vex product, only the FIRST Vex Challenge game. Just like LEGO makes the Mindstorm kit, Innovation First produces the Vex kit.
Vex is the "middle-ground" between FLL and FRC. I have seen multiple posts concerning how much harder it is to "tinker" around, deconstruct, and reconstruct a Vex robot than a Lego one. Coming from an FRC perspective, I found FVC bots to be much simpler to tinker and play around with. In vex it can take a couple hours to maybe a day depending on how involved and how many "custom" parts you have to make to create a robot feature, while in FRC it would take much much longer than that. An FVC design problem can typically be ironed out in a single build meeting, maybe two, while in FRC, if you design fails, you're often up the creek without a paddle, and you have to abandon that feature.
With the Vex kit, while there are limits to what you can do with the "stock" material, it presents a whole new feature to the educational and creative process behind creating a final product. While with Legos you can tinker, build, re-build, etc all with stock pieces, with Vex you have to do substantially more designing beforehand, and you are introduced to many more mechanical and fabrication issues. You have to decide, how, where, and actually manufacture custom pieces from the stock pieces to pursue more ambitious designs. I think that was an intentional, and if not then still advantageous, feature.
Also keep in mind the squarebot was meant to be what it is, not something else. It was meant to be a simple, robust platform for a customer to get a feel for the Vex kit when they first purchase it. It may be hard to re-design, but that's because it wasn't meant to be re-designed. It would probably be alot simpler to actually build a custom platform from the starter kit if you wished to tinker around and play with gear ratios, etc more.

[ManicMechanic]

Originally Posted by Lil' Lavery

Vex is the "middle-ground" between FLL and FRC. I have seen multiple posts concerning how much harder it is to "tinker" around, deconstruct, and reconstruct a Vex robot than a Lego one. Coming from an FRC perspective, I found FVC bots to be much simpler to tinker and play around with.

Yes, Vex is the "middle ground", but where you start from (FRC "moving down" or pre-FRC "moving up") greatly colors your perspective on Vex and how willing you are to work with the system. While it's not a good idea for pre-FRCers to indulge in too much complaining, FIRST will need to be sensitive to the frustrations of pre-FRC teams if the Vex program is to grow. Otherwise, Vex teams will largely be siphoning students from FRC teams, simply serving the same students in a different way, rather than attracting new populations to robotics.

Our team reflects the dangers of ignoring the difficulties. We were a very successful FLL team for 2 years and "aged out" in time for the 2005 FIRST Vex Pilot (FVC-38), which we were privileged to attend. During 1-month build season, the team had good ideas, but couldn't make most of them work. I'm not an engineer and relatively non-technical, so I wasn't much help, and there were no adult mentors in town available (we did contact the FIRST Senior mentor 100 miles away, but there were limits to what can be done over the phone with someone who had never seen the Vex kit). The Atlanta experience was awesome, but the team didn't feel they'd learned enough to "make things work", and more importantly, they didn't see a way that they COULD learn. As a result, when we returned home, each of the 4 members took home a kit, but those kits have gone largely untouched all year, and the team's enthusiasm for robotics in general was largely doused. If there had been a Vex regional pilot in our area this year, we would not have participated.

This is in marked contrast to Lego Mindstorms. My son begged me to buy him a kit, but I was a tightwad, so he saved allowance for 2 years to get it. For the next year, he couldn't put it down and built and re-built projects from every available book from the library on Mindstorms (more than a dozen) and scoured the web for building ideas, and his teammates immediately caught the fire for robotics from him. If the team members had the same enthusiasm for Vex as for Lego, they would be posting here, not me.

I managed to coax a reluctant team back into robotics by entering a competition that potentially involves both Lego and Vex. This time, I opened my wallet and stocked up on Vex parts during the 50% sale, but the team declined to participate in the Vex portion. Having regained some of their confidence, I'm hoping that they will give Vex another try, and I've come to the conclusion that the following resources are essential in attracting AND KEEPING other pre-FRC teams.

1. Adult mentorship is key. While many of the teams at the 2005 Pilot had students who had never participated in robotics before, it was my impression that almost all the coaches had some FRC experience, or close connections with someone with FRC experience. Our team model had previously been kids learn by doing, researching, and doing again, then me learning from them. The team needed more guided instruction, which so far has not been found in our region.

2. Written resources that are organized in a systematic, orderly way are also needed, beyond the Squarebot instructions. These could include tutorials, overview books like "Building Robots with Lego Mindstorms" for Vex, or a "Constructopedia" of several cool projects with building instrucions. While veteran builders may feel these are "crutches", for teams in isolated areas without engineers, these mean the difference between making progress and stagnating.

3. The programming platform should have been one of our first purchases, because of the step-by-step tutorial. This might have captivated the team's interest enough to overcome the frustrations if we had purchased it early on.

There may be hope for us yet! I may have found a mentor (former FRC college student) only 40 miles away, and the team is willing to commute to him.