After some smack-talking in the office regarding robot fighting, I bought the bluetooth robot kit from DealExtreme a week and a half ago. While I was waiting for it to come in, I started trying to find help for how to put it together and program it. I found a word file that contained some helpful things, but it was sort of obvious even without the kit in front of me that it was going to be a challenge.
I took pictures of the process of putting it together and will document all that out sometime soon, but I want to start with an overall review and impressions of it for those considering buying one.
Pros: It's all there. The wheels, the motor driver you need to run the wheels, the sensor shield to plug it into, the arduino itself and the chassis it all mounts on. If you have no idea what you really need to build a robot, this has everything you need to do it.
It comes with an ultrasonic sensor on a servo that swivels 180 degrees. It comes with three line sensors if you want to have it drive along a line. It comes with a bluetooth module, and an IR reciever and remote control. It comes with all the screws and spacers (well, mostly. I never ran out of screws, but I had some that just wouldn't fit). It was really cool to know that I have all the parts I need in front of me. All the parts are from DealExtreme, so you can search for that part to find more information and docs on it if you need to.
Cons: This is not something you work on with little Johnny or Jane, unless you have a remarkable amount of self control or don't mind giving them some vocabulary lessons.
The assembly of the physical parts is very frustrating. The screw holes in the plastic are always off from what's supposed to be mounted there by a touch, and I ended up having to sort of cut/scrape a hole in a certain direction so I could get the screw to fit. One of the first things you have to do is cut apart something they give you so it can fit in this little cavity. I think someone got this to work and just released it without trying to make it a finished product. The whole ultrasonic rotator servo part is hacked together out of a part for something else as evidenced by the special plastic pieces you don't need. It works, but if you're the type that is looking for something super polished, it's not really this kit.
Lastly, the bottom part with the motors for the wheels comes preassembled, but you'll need to adjust them because they didn't leave a lot of space for the wheels to not scrape against a part of the chassis somewhere.
The instructions aren't clear. Most of the complaints about this online have to do with the instructions. The word document starts out with incredibly detailed instructions of how to put the servo the ultrasonic sensor sits on (which began in this world as an email to a guy named Jim, since someone forgot to remove signoff). Then there's an essay about arduinos followed by installation instructions for them, then some wiring diagrams in Chinese and some large copy/pasted programs for the various modules. It's really disjointed, there are pictures of robotic cars that aren't the one you bought, and it's confusing to know what advice to keep and what doesn't apply. Having pages and pages of arduino code in a word doc (intersperced with words and pictures) is annoying to page through, too.
I don't know where the bluetooth part is really supposed to go, they have a bunch of code for it but it's not hooked up in any of the pictures. Same thing for the line sensing parts, although I don't want to hook those up anyway.
Final word: I mentioned little Johnny or Jane up there. I think if an adult assembled this and got everything wired up and had some sample programs, it would be fun for kids to play around with - provided your kid is interested in programming and not into fast, durable cars (this is not a fast, durable car).
This kit is definitely worth it if you know what you're doing in terms of the standard arduino process of looking up info on the various boards to find the libraries you need and how to use them. I ended up ignoring most of that document and went into it looking up the various modules part by part and building off each other. I had a program to control the robot with the IR remote rather quickly.
With the non electronics part of building it, just don't expect perfection. You're going to have to struggle getting screws in the right places and improvise some stuff to get it put together. There's also a couple places where, once you realize what they want you to do, it's easier to do something slightly different.
The big great thing for me was the plastic chassis to mount everything on and having that is a big help from having to design and make one yourself. But if you have access to somewhere where you can laser cut acrylic and are maybe kinda new but have a friend who can help you figure out how to position screw holes, you'd save a lot of time having to widen screw holes to get stuff to fit correctly, and you can have something more original.
Oh, and lastly, it doesn't take a standard battery size, it takes two 18650 batteries, which you can buy on ebay but I don't know where else.