Smart Robot Car Chassis Kit with UNO R3 Module - Educational DIY Toy, 2WD with Battery Box and Speed Encoder for Tracking Obstacle Avoidance - Designed for Beginners to Learn Programming

I'm giving this 5 stars for the price and because my kit actually did come with pre-soldered motors, as well as a mini-CD with sample code and a video showing how to assemble the kit.I ran into two minor assembly problems: 1) The holes for connecting the caster wheel were too large (it slipped right over the nuts that were supposed to hold it on). I didn't have any washers of the right size, so just I used a little bit of cardboard from a tissue box to fasten it. And 2) the battery pack didn't have the extra wires coming off the plug, so I had to chop the plug off.Neither issue was bad enough to drop my rating. I still think this is a very nice kit for the price. What I really like is that almost all of the parts will be useful in future projects.

As others have pointed out, this kit isn't exactly perfect. You will get all the parts you need to build this robot but no part of the assembly will be without a little challenge. I would not recommend this kit for a beginner to Arduino or to electronics. Nothing will work right from right out of the box. Someone with a little experience can massage this kit into a fun, working robot. If nothing else, you get a lot of good parts for the price in this kit.First I'll share some of the assembly challenges I experience. The Arduino and the motor controller can only be secured to the acrylic with two screws each. If you want more than that you will have to drill your own screws. For now I've opted not to and it holds together well enough.The battery case is meant for six batteries and only one hole lines up on the acrylic. I got around this problem by using velcro to hold the battery pack in place.The servo mount already had the servo arm mounted inside it but the screws were installed from the wrong side. The included instructions suggested a "fix" of installing a screw through the center of the arm and into the servo shaft which will work but I chose to also fix the incorrectly installed screws. For all this hard work you will still find that the screw holes in the acrylic do not quite line up with the screw holes in the servo base.Others have noted that the instructions for wiring the motor controller are incorrect. I found that to be the case in my kit too. However, where others found that the problem was the numbering of the analog pins was off by one, I chose to use the digital pins and reserve the analog pins for future use with actual analog devices.For assembly, the last problem I had was the instructions calling for connecting the power switch between the Arduino and the motor controller. This is not ideal as the result is that the Arduino board is always on once you have installed all the batteries. I cut the red power lead of the included barrel connected and connected the switch right after the battery pack so that once the switch is flipped the whole robot turns on.Others have complained about the rear caster needing washers or not quite lining up. Funny, but that was the only part of my kit that was without problem.Another reviewer, Perspicacious Consumer, pointed out that the ultrasonic scanner is "crappy." I agree.As for the included Arduino sketch, it stinks. It is a very poorly written piece of code that will have to be edited just to get the kit to work. At bare minimum you will either need to adjust the analog pin connections as pointed out earlier or you will need to change the pin values in the sketch. Also as Perspicacious Consumer pointed out, unless you enable PWM by uncommenting the analogWrite commands, your robot will run at full speed. I have hardwood floors in my house so I need to run the motors just barely above stall speed or the robot "peels out" by spinning its wheels in place without grabbing traction.There is one last significant problem I experienced with my kit. No matter what tricks I tried, I could not get the left and right motors to turn in sync resulting in the robot veering in one direction or the other. The kit includes shaft speed encoders but for some curious reason it does not include the photo-optical speed sensors needed to read the encoders. I've ordered a pair of speed sensors and will update this review with my results once they are installed.Despite all I've mentioned above, this kit is pretty fun and I've already started writing a custom library for it. It has a lot of potential and room for refinement and additions but it will require a little know-how and perseverance to get it going.

The media could not be loaded. This is a great, low priced robot kit. The kit doesn't come with any instructions or code so if you are looking for a step by step, Instructable style, kit this is not the kit you should be buying. This kit is a bunch of independent pieces put together into one package then sold as a "kit" and as a result unless you drill additional holes in the robot chase you are not going to get all the screw holes in the PCBs to align with chase holes.In all this is a fun few hours of layout, assembly, piecing together, and coding.

I'm a geek. I build things, I modify things, and I'm not new to Arduino. I wanted something that I could learn more with, and I chose this kit for the included parts and the low price. I used the instructions in the video just to see the contrast between those and the ones linked in others comments. The video and instructions that come with the product are no good. Was able to use instructions mentioned by other reviewers.With it all done, I uploaded the code and powered it up. It didn't work as expected, and it wasn't avoiding any obstacles. I grabbed another arduino and and used a test sketch, and found that the ultrasonic transducer didn't work at all. I checked a few solders on it that looked sketchy but to no avail. It's a dud.I originally thought about getting one of these kits for my nephew but with worse than terrible instructions and bad parts, I can't. I'll have to spring for a more expensive kit with better instructions and some QA for parts so I don't send him broken stuff!Update 5/13/19: The Arduino clone that it came with died. I ended up replacing the motors with continuous rotation servos and wheels that slowed this thing down to reasonable speeds. Save your money, buy a better kit, or else buy the parts separately and scratch build.

I have purchased 2 of these kits. Just can't beat them for the cost. The instructions are useless. Neither kit I purchased had the battery case given in the instructions, which messes up parts placement on the chassis. Good instructions and code are given in the links in the Questions section of the product descriptions on Amazon. This would not be a good kit for a beginner - on the other hand, it is challenging and fun to sort/search/learn your way to getting this working. I recently bought the Lafvin kit for just a few $ more. Much better instructions and the code works.