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[on:]

Hi all,

I've read all that I could on arduino for robotics gain a world of experience and have been using an arduino uno board to hammer down the concepts.

Now I want to buy my first robot kit and have some clear goals so here they are:

1. Dagu Quadot which uses a Arduino Mega replica( Black Spider) with an Atmega 1280 at it's heart
http://robosavvy.com/store/product_info.php/products_id/1669

2. The DfRobot 4WD which has been very popular and uses a Romeo 328.
http://robosavvy.com/store/product_info.php/cPath/21_1200/products_id/989

I plan on on adding a ultrasensor to either of them and make it an obstacle avoiding robot.
The most important part is I plan on using Oleg's Host USB 2.0 shield that allows ADB connection to Android which basically transforms it into a Google ADK and removes the hassle of bluetooth connectivity when you need reliability and speed but I'm not sure if any of these boards have problems with the USB shield, this is untested territory.

The dfRobot has  4 motors while the Dagu has 8 servos.

Any opinions? I just wanna get some feeling of accomplishment because it was always my dream to build a robot, I know this is a kit but I can still add a lot of awesome things to it to make it into my own creation.

[Reply #1 on:]

Have you thought about other options? A kit is an easy way to go for a first robot, and will definitely remove a lot of headaches. If this is your first option, you'd probably have the best luck with the second kit (the wheeled one). Robotics is difficult all on its own; no need to add the headache of walking if you don't have any experience with a general wheeled platform first. I only say this because you might end up getting frustrated with a walking robot, and robots in general - when it is really the issue of walking, and not robotics, that would make things difficult and frustrating.

Here's another low-cost option - if cost is a factor:

http://www.budgetrobotics.com/item/ArdBot-Chassis-Kit-340

You'd have to supply other components, of course (so it may or may not end up being cheaper than your other kit options).

Another option to consider is repurposing an old radio-controlled toy car (something made by New Bright or Nikko) - in many thrift stores (my favorite is Goodwill) you can find perfectly serviceable R/C toy cars for $5 or 10.00 USD. All you have to do (once you know the motors, gearing, and steering mechanism are OK), is trace the connection from the motors (or other actuators) to where they connect on the PCB back to the control system (in most toys, its a single R/C chip). Most of the motors go thru some kind of discrete component h-bridge made from transistors or mosfets, and eventually end up at the IC. You have to also trace the power and ground connections to the h-bridge, then carefully remove everything not needed (R/C control IC and support components), leaving you with the h-bridges in place with power and ground, so that you can splice the Arduino in fairly easy.

Not for the faint of heart, but you'll definitely get a good education in the process, you'll have a cheap robot platform (in some cases, better than anything you could buy), and the satisfaction of knowing you did it all yourself...

Good luck - whatever route you take! You'll have an exciting and educational time no matter what, no doubt.

[Reply #2 on:]

2. The DfRobot 4WD which has been very popular and uses a Romeo 328.
http://robosavvy.com/store/product_info.php/cPath/21_1200/products_id/989

I got one of these, and I totally love it!

It was easy to put together, can take a lot more beatings than it should ever get from normal use, and it can actually drive over a lot of things, like high doorsteps and so.

[Reply #3 on:]

I agree with cr0sh... go with the wheeled version since it's fairly simple to make it move and will still give you plenty of headaches if you want to go deep enough...

Whilst on the legged robot, you'd have to make it walk, on the wheeled version calculating trajectories, controlling direction (less than a milimeter difference on the radius of the wheels can cause a big impact on the "linearity" of the movement) and even (if you put a GPS on it) global positioning can give you plenty to learn from.

I also find the wheeled robot a bit more robust than the legged one and quite a good platform to evolve. Meaning that the base of the robot looks big enough to add more sensors, a different control boad with more memory, etc, etc, etc...

But it all depends on what you really like and want to develop on.

Also, you could buy just the hardware and different control boards for the robot base.

[Reply #4 on:]

Oh I totally forgot... I don't use a Romeo 328 for mine, I use a Seeeduino Mega with a WiShield 2.0, because I wanted to make sure I didn't run out of pins

And then using one of these to drive the motors instead http://www.seeedstudio.com/depot/l298-dual-hbridge-motor-driver-p-284.html?cPath=170_173, as you can see in the movie, it is working pretty well.

[Reply #5 on:]

Thanks a lot guys I went with the DFRobot kit with the Rome 328 in the end, the link I've posted is a good place to buy if you're in the UK since they have it in stock and it's going to get delivered in 48 hours according to the seller.

The purpose of my project is to have the robot car controlled by my android phone connected through USB in a two way communication pipeline. I plan on using Oleg's USB Host Shield(which transforms your arduino into a google adk that works through android adb):
https://www.circuitsathome.com/products-page/arduino-shields/usb-host-shield-2-0-for-arduino/
It's compatible with UNO,Duemilnuove, Mega and Mega 2560 and arduino clones with standard connector layouts. Does the Romeo 328 fit in that category? I do not have the required knowledge to figure it out by myself, but I'm willing to learn more if anyone can tell me how I can figure out this stuff out from specifications.

[Reply #6 on:]

I got the DFRobot 4WD platform a while ago and I'm having a load of fun with it.
It goes together quite easily and offers a lot of space for sensors and other gizmo's.
You can always screw a regular Arduino on it, which I did, with a motorshield. Works like a charm!

And as already said, it will still give you plenty of headaches getting it all to work properly.

[Reply #7 on:]

Think about the value you get for your money in each. How good of quality are each? How many motors and parts does each have? Just some things to think about. It's your decision to make I can't really decide for you.