Vex Vs. Edubot Vs. RCX Vs. NXT
 

After graduating from FIRST (temporarily, until I start my own team after the army!) I want to do robots on my own a bit.

I don't have an electronics lab yet, so I would be looking to start from a kit.

I used to own an RCX but someone <cough>Mom</cough> threw it out or gave it away or misplaced it.


so basically what i am asking is this:
what would you recommend I invest my money in:
Vex
Edubot
RCX
NXT

The edubot doesn't come with any robot parts i think and it a bit pricey compared to the VEX.
The RCX is discontinued so I would REALLY need a good reason to get one (a good deal is a good reason).

the real dilemma is the VEX versus the NXT.
could someone more knowledgeable maybe shed some light on the pros and cons of each.

Thanks!
-Leav

(p.s I will be programming in C anyway.)
(p.p.s I hope this is in the right forum...)

Re: Vex Vs. Edubot Vs. RCX Vs. NXT
 

I'd go with Vex over NXT any day. ;)

Vex: 16 analog/digital/IO ports; 8 PWM motor ports; 6 Interrupt Ports

NXT: 4 input ports; 3 motor ports

Vex has so many more motor and sensor ports available, and it provides a great platform for future projects (like building a Bluetooth module or serving as an FRC co-processor). Vex is also better suited for FRC-type robots, while NXT is more suited for making toy-like robots.

Re: Vex Vs. Edubot Vs. RCX Vs. NXT
 

I got a Mindstorm complete set at a garage sale last week: $3 !

I heard MIT has a controller for it that has more motor outputs and stuff - and they are for sale at a reasonable price

anyone know anything about this?

BTW - Legos are great if you nylon-tie-wrap the finished design all together :^)

Re: Vex Vs. Edubot Vs. RCX Vs. NXT
 

I agree with VEX aswell.


With a male to male pwm cable (doesn't need to be long) any existing pwm device can be used with the vex kit. This will give you a more cost effective solution because I'm sure you can borrow some older sensors from your team and such.

Also, stating the obvious here, but Vex has more inputs/outputs and It currently has a much larger (especially if there really will be 35 regionals) support group and knowledge base.

Re: Vex Vs. Edubot Vs. RCX Vs. NXT
 

If you want to get nitty gritty with the electronics/programming aspect of it, I'd recommend not using any. Build your own solution with the AVR ATMega chip series. You can get the development board (STK500) for about $80, and it includes pretty much everything to get things started off for you.

Re: Vex Vs. Edubot Vs. RCX Vs. NXT
 

Gotta disagree with you here, the STK500 is great, but none of the DIP packaged AVR chips have more than a few timers/PWM generators, so that limits your motor output options.

Re: Vex Vs. Edubot Vs. RCX Vs. NXT
 

A VEX kit would be giving you the most bang for your buck here and it's the closest thing to building an actual FRC robot that you can/could buy locally. Seems that Radioshack's online store has permanantly slashed prices in half and they still have the kits in stock Right Here.

However, I do have to say, if it comes down to getting an RCX or an NXT, go for the gold and get the NXT. In my opinion, it's going leaps and bounds beyond the old mindstorms kit and any team who utilizies its functions will have a pretty decent advantage over those with the old Mindstorms kit.

Re: Vex Vs. Edubot Vs. RCX Vs. NXT
 

I would have to also side on the side of Vex...

When compared to any of the other alternatives you provided, it just blows them away. Also I would act soon...because without a 50% discount at Radioshack they can get expensive very quickly.

Re: Vex Vs. Edubot Vs. RCX Vs. NXT
 

[quote=Ryan Dognaux]A VEX kit would be giving you the most bang for your buck here and it's the closest thing to building an actual FRC robot that you can/could buy locally. Seems that Radioshack's online store has permanantly slashed prices in half and they still have the kits in stock Right Here.

QUOTE]
I agreed!

Even though I have 3 or 5 RCX units (not really sure because of my kids keep using them for different projects) and one VEX at home, I preferred the VEX. The options for the VEX is growing day by day and it is closer to the FRC world. Definitely try to visit the local RadioShacks for bargain parts!

I found that Home Depot supplies a variety of metal decking brackets that makes great custom parts for my VEX projects. They are easy to cut, bend, shape and drill.

Re: Vex Vs. Edubot Vs. RCX Vs. NXT
 

Last weekend I actually went out to RadioShack and bought some Vex stuff after learning that it was still in stock, and still at half price. It's better to buy it now while you can still get it at the lowered price.

Here's a picture of it all:



Shown in this picture is:
1 Starter Kit
1 Programming Kit
1 Hardware and Metal Kit
1 Tank Tread Kit
2 Servo Kits
2 Motor Kits
2 Light Sensor Kits
1 Ultrasonic Range Finder Kit

Since they didn't have any of the battery kits in stock, I bought some rechargable NiMH batteries. I just wish I had enough for the transmitter, because the cheap batteries I used for that died out within 5 minutes of use. Now I'm just playing around with autonomous and plan on making a robot that has the same characteristics as myself (i.e. hates the light and always travels towards darkness) until I get some more batteries.

Re: Vex Vs. Edubot Vs. RCX Vs. NXT
 

I think it depends on what you want do with the kit. First the vex costs less and does more than an EDU, and the NXT does more than an RCX.

If you want to use different/custom parts the vex is the way to go. If you want to something to that's fast and simple to use LEGO is the way to go.

Re: Vex Vs. Edubot Vs. RCX Vs. NXT
 

Guys, just a point to think about, in Israel we don't have "locol Radio Shacks and Home Depots". :D

In my opinion vex is the best system from the above list, although to really build a cool robot you need to buy a lot of expansion packs and it can get fairly expensive. I was lucky and was able to bring a lot of vex stuff to Israel, so Leav if you have a way to do so then get vex.

Re: Vex Vs. Edubot Vs. RCX Vs. NXT
 

Thanks guys, you really helped me make up my mind.

I will go with the VEX for a couple of reasons:
-cheaper (kit and body parts) and easier to expand with scrap stuff (scrap computer cases etc.)
-More expandability and better standard compliance.

I already know I will only get the VEX kit if i manage to get the prototype programming kit. (so i can program in real C)

so now I have two questions:
-is there any other way to get the prototype programming kit not from the vexlabs? because the phone method is a bit tricky for me... (I live in israel).

-Where can I get more sensors for the Kit? what kind of sensors do i need?
for starters I would like a ultrasonic range sensor and a rotation sensor with a good resoultion (accurate at 6 degrees).

Thanks alot guys!
-Leav

Re: Vex Vs. Edubot Vs. RCX Vs. NXT
 

Vexlabs sells a pretty decent ultrasonic range sensor. The way it works is very comparable to Parallax PINGs and other similar brandings, but Vex went out of the way to provide pins for I/O signals. This is very helpful when using a preconfigured control board, like a FRC or Vex controller.

As for a rotation sensor, it depends on what kind of rotation yo are trying to measure. I will assume you would like to sense the rotation of a joint. You should have no problem wiring up a potentiometer or encoder. There's been numerous discussions here on which resistance pot to use and wiring techniques.

Vexlabs sells a 90 ppr encoder. It's non-quadrature, so you'll have to cook up some way to keep track of direction. I'd start off with that and then put those good old problem solving skills to the test. (I mean thats half the fun, isn't it? ;) )

Re: Vex Vs. Edubot Vs. RCX Vs. NXT
 

For an ultrasonic senor check this out you just solder a PWM cable to the vcc, gnd, and analog pins. It is fairly accurate (about an inch) up to 20'.

Hope this helps. :)

Re: Vex Vs. Edubot Vs. RCX Vs. NXT
 

Leav I am currently in the US and if you want I will be able to stop at Radio Shack and pick some stuff up for you (small things like sensors and programming pack, not a kit).

Re: Vex Vs. Edubot Vs. RCX Vs. NXT
 

Hi thanks David... but I wouldn't want to hassle you with all that... :) I have a friend who's coming over from the states soon, so i'm buying it all online and shipping to him... (hope he remembers to bring it...) :rolleyes:


My only real problem is the prototype programming kit. i sent them an e-mail and called but it was like 19:00 at texas when i called so they probably stopped working... :(

the whole VEX thing hinges on the prototype programming kit - i want to program like a big boy! :D

if anyonecould help me with that i would appreciate it...

thanks again!
-Leav

p.s.
the rotation sensor is for a lock picking robot (combination lock) which usualy have 60 points per rev. so i will need something that can find the angle accuratley time after time.

-Leav

Re: Vex Vs. Edubot Vs. RCX Vs. NXT
 

You can always gear up/down the VEX potentiometers to get the resolution you need. Typically it's the sampling rate (and the lack of quadrature) that limits the possibilities with the VEX pots... Sounds like a very interesting project.

BEN

Re: Vex Vs. Edubot Vs. RCX Vs. NXT
 

Where in Texas?
Jane

Re: Vex Vs. Edubot Vs. RCX Vs. NXT
 

Leav, you can use the official Vex Programming module and still program in real C (as in MPLAB). All you do is when you buy the Vex Programming Module you only install the USB-Serial driver, and ignore installing EasyC. The prototype and the official Vex modules are both the same price at $99 USD, so I'd just go with non-prototype one. :)

Re: Vex Vs. Edubot Vs. RCX Vs. NXT
 

This is entirely true. I've been playing with my vex kit since april and programming soleley in Mplab. Just use the same install cd that comes in the KOP at kickoff.

Also, Any pwm based sensor will work. Because vex has male inputs, you'll have to wire a short male to male pwm cable to use as an adapter for non vex sensors.

Re: Vex Vs. Edubot Vs. RCX Vs. NXT
 

Although I would agree that Vex is the way to go; All Vex stuff is out of stock on Radio Shack's online store and is getting harder to find in local stores as well.

Re: Vex Vs. Edubot Vs. RCX Vs. NXT
 

I've found that a lot of the radioshacks (at least in my area) still have VEX products even if they're not displayed out front. Make sure you ask a person working there if they still have anything in stock. I went to three different ones today looking for the tank tread kit and none of them had it, but they all had the kits in stock.

Re: Vex Vs. Edubot Vs. RCX Vs. NXT
 

http://www.vexlabs.com/vex-robotics-downloads.shtml

Adding to what Art said, there's the default workspace that will open up in MpLab or your favorite source editor. Compile it with MCC18.

Re: Vex Vs. Edubot Vs. RCX Vs. NXT
 

WVU (West Virginia University) uses those boards for education.... its called the Handy Board.

When they bought them at least the boards were very expensive but can't remember exactly how much he said they are. Nice thing about them is they have a pretty large LCD display and built in IR comm.

See it here: http://handyboard.com/

Buy one here: http://www.robotstorehk.com/handyboard/handyboard.html

-Q