OrionBot here with a review of the mBot!
The first video here includes and introduction, the unpacking of all the components and the assembly the mBot. Here are my comments:
Right at the start I knew I liked this kit. The packaging was very neat and well laid out. The box it came it was strong and reusable. The chassis of the mBot is made of sturdy aluminum with a great metallic paint job. The chassis in the kit I received was green and is shown in Figure 1.
Figure 1: Metallic Green mBot Chassis
The organized packing of the kit made unpacking and sorting the parts of the kit easy. All small parts were separated already in their own small bags.
I liked how the individual parts were labeled – like the Me Ultrasonic Sensor, mCore, etc. Also the interfaces and key components of the mCore board were very well labeled which will make using it much easier, especially for kids. You can see the labeling in Figure 2.
Figure 2: mCore and it’s Great Labeling
The only recommendation I believe I had in pulling the parts out of the box and checking them off against the diagram in the booklet was that the small bags of nuts and bolts and screws were lot labeled. If the small bags were labeled with the type of bolt, nut or screw (i.e. M2.2 Screws, M4 Screws, etc) it would have taken out any guess work involved, especially for kids.
I had one component that was defective. They 4xAA Battery Holder was missing one of the spring contacts. The spring wasn’t found loose in the box so I concluded the holder was defective from the factory. A good quality control would have caught this, but I suppose a few bad eggs can slip through from time to time. For kids this would probably have been a dead end for using the mBot kit. As for me, I simply scavenged a spring from another battery pack and jammed it into place to make the battery connection. The battery holder is shown in Figure 3.
Figure 3: The Defective Battery Holder
My kit came with an extra component. A LED Array was tucked inside the chassis. My immediate thought was how neat it will be to use this array to add some character to the little mBot with eye and/or mouth expressions. They only issue I saw was that there were no directions on how to use it. The instruction booklet did not reference it at all. Fortunately the MakeBlock website is very user friendly and I was able to get the instructions from there.
Assembly the mBot took about 30 minutes in the video. I discussed each step and my experience in executing it. I have to admit, one technique used the booklet that almost tripped me in the early steps was that the steps are numbered clockwise on each page instead of a ‘Z’ pattern. Each page has 4 quadrants with a step in each quadrant. Steps 1 and 2 are across the top, no surprise there, but then Step 3 is below Step 2 and then Step 4 is to the left of Step 3. After the first few pages you get used to it.
Steps 1-4 install the wheel motors and the wheels. These are pretty straightforward but kids my have a bit of difficulty in first orienting the motor in the right direction and then holding the threading the nuts in place. A pair of needle nose plyers may help here. The supplied screwdriver seemed a bit small for the wheel screws and I had some concern of striping the phillips heads, but with a little force there was enough catch on to the screw to tighten them all the way down.
Steps 5-8 install the line follower sensor, roller ball, range finder and mCore standoff posts. I really like the threaded holes in the chassis. This is a great feature that makes it even easier to assemble. It can take a moment to understand the coorect orientation of the line follower cause the picture is a bit dark, but you quickly figure it out. The wires for the motors, line follower and range finder aren’t shown in the installation steps but show up later. Step 8 shows the wires already routed which is a little confusing. Might need some arrows indicating how the wires are to be routed during the installation steps.
Steps 9-12 install teh battery holder, mCore board and Bluetooth board. The orientation of the battery holder may trip someone up. I changed the orientation of the velcro atleast once. I like the extra inset photo that gives some extra orientation information for the bluetooth module. On installing the mCore board an orientation key would help. Maybe something as easy as colored dots that you line up. A blue dot on one corner of the board lines up with a blue dot on the chassis, for example.
After the assembly is complete there is a wiring diagram that I really like. It is a good figure to use to check all your connections.
I decided to test the assembly instructions on my 11 year old son. I disassembled the mBot and gave it to my son to reassemble. It took him about 40 minutes to put it together. While working through the instructions he came to me couple time with questions. He asked “where do the wires go?” after getting to about step 5 when the line follower sensor is installed. I told him that Step 8 is meant to show where the wires route, but I also had to describe it from the underside since the picture only shows the top. He asked “how do you connect the wires?”. This one caught me off guard until I remembered that in this age of wireless telephones he’s never had to connect that type of connector! He also fiddled with the battery holder some before figuring out the orientation that worked and let the holder slide under the mCore board. Overall he said that assembly was pretty easy. He thought the wiring diagram on page 7 was helpful, especially the little figure that illustrates how to connect the motors.
My overall impression of the packing and assembly of the mBot was very possitive. It is a well thought out robot kit and easy to assemble. Using the telephone-type connections is a neat idea. I think my son and I have pointed out a few nits here and there but nothing that would hold most anybody up from assembling this sturdy, cool looking robot. Can’t wait to test it out!
Long delayed testing video! I ran into computer issues so I’m just now posting this video. The second video shows the tests of the mBot’s basic functionality using the remote and using my Android phone. I ran into no issues with getting the mBot to work. Instantly it was able to demonstrate obstacle avoidance, line following and remote control cabilities. The mBot phone app looks really slick but takes a little getting used to in order to accurately steer the mBot. My kids enjoyed experimenting with the mBots functions.
LED Matrix Modification
Using my own nuts and bolts I’ve mounted the LED Matrix above the Ultrasonic Sensor to create a set of ‘Eyes’ to give the robot some emotianal expression cabability. I haven’t created the video yet, but suffice it to say the PC software for programming mBot was easy to use once you spent a few minutes exploring it’s drag and drop functions. I got the new ‘eyes’ working in no time.
Update: March 10, 2016
Finally getting around to adding the final video to this review. I had incorporated the LED matrix differently than the instructions showed. The instructions would have you remove the Ultrasonic Range Finder and install the Matrix in its place to become the mBots “eyes”. I wanted to leave the range finder in place so that I didn’t lose the object avoidance capability. I attached the range finder on top of the Matrix so that the Matrix became a new ‘Mouth’. I’ve attached a video clip where I’ve programmed the mBot to short sequence of moves. With each move the mouth changes its expression. The only hiccup in this was the first time I made the program I got garbage on the Matrix. I found that I had to put short pause times in between wheel commands and Matrix commands. The wheel motors must generate some noise in the controller module or power bus that scambles the Matrix. Short 0.2s pause times work but slow down the responsiveness of robot. I’m going to incorporate the expressions in the object avoidance program to make his wanderings around the kitchen a little more fun.