loog 003: building Charlie the robot

The next Robot we started to assemble was Charlie, a cute little fellow. He has smaller than "Blast", but uses its 4 motors for his leg and arm. So he can move each arm independently and the 2 motors for the wheel make it possible to move and steer around the room.

assembly

Of course, we had to disassemble the last robot to get all the parts for this one. remote4 control program was easy to write with scratch. One downside of this robot is the tiny wheel in front and back to stabilize the Charlie, which makes it impossible to go over small gaps like the edge of a carpet.

There is a lot left over parts from the set. You can turn it independently, it's linked to arm rotations. But their extras you can do, like building a little drum set.

 

The standard build only uses 4 motors.The extra instructions included adding the colour sensor and the distance sensor. It's placed on top of the head and on top of the front wheel, which breaks its nice esthetic. I will try to find a better placement for the extra sensor.

Charlie completed build

 Here is the scratch program top Charlie movable with a game-pad.

basic movement control by a Game-pad

For arm movement, I could not figure out to get it working with the shoulder R/L buttons in a satisfying way. I think it's time to shift over to Python programming. 

 

Charlie with Drum kit

 

Lego removed the autocomplete Python coding functions from the App, it was buggy and they are working on new version. Bummer! nether less I try stick with Python for the programming.

 

log 002: closer look and test runs on the Blast Robot

 here is our Robot named Blast from the last building session.

cool and modern-looking robot

there are serval more exercises/tasks,  you can do with Robot with instructions from the App. 2 plus of the tasks also available as python program.

Examples of activities that come with the app by default

the scratch programs are really cool and easy to use. you can drag a program block onto canvas and double-click on it if the robot is already connected via Bluetooth. it will perform the action of the block right away. very intuitive! 

But we use python programming, its a good learning and gives later more possibilities. 

here is a little comparison of the same program in Scratch and Python:

It seems the python is twice as long because of the display animation code in form of a "Hexa" looking code (green). Wired choice and I still have to figure out how the animation editor with python, but I will explore the python programming myself in the next robot build.

One cool feature of the robot, you can open the front plate of its chest and you can see the mechanic in action. With the open front plate from his upper body makes him like Johnny 5 from "Short Circuit" movie.

with the front plate open, you see the gears working.

 

 

One Issue with this lego set and this robot build. you can only rotate the head and both arms at the same time because the inventor sets only come with 4 motors. so we have 2 motors for each leg and 1 motor to activate the darts. this leaves 1 motor for both arms and the head.

the Robot Dart shooter on the right arm 

I think we are done for now with the Blast Robot, we come back later to it and modified it by adding 2 more extra motors you can buy on the Lego Website. It's a really rad-looking model and it would be slick to add more features to the base model. 

But now it will be time to try the next robot build which comes with Set.

log 001: building the Blast robot with remote control

My son decided he what to build the humid robot named Blast. Good choice, a robot with blaster and hammer, how you could go wrong with it! The building instruction was quite clear. The first thing you build is a workbench to hold the head and upper body, very clever !

Torso finished and ready for a test

After updating the hardware, we build the workbench and place the head on top. Then the app gives the option to run test programs, very nice idea.
After the body was finished, the torso was next to build. Also, no big issues and done fairly quickly and fit great on the workbench. then we jump right into the arm construction. Once we were done, the app offers us to test our arm out with a program, which is very nice and motivate to build the rest of the body.

Building the legs was very simple. The robots use the wheels to move around. A real walking robot on 2 legs would extremely difficult. The wheels work pretty good and can drive across any kind of surfaces and do not get stuck on carpets or other gaps, which is a very good.

We remove the robot from the workbench and run an example program. Everything worked great. We build quickly the rocket launcher extension because the robot was without a rocket or laser is just half a robot, right?

 

The color and distance sensor are placed on the left arm, in front and under the elbow, quite odd at first. It’s like in Andy Weir`s “The Martian” where the astronauts have a camera on the arm to point items on the ground to see without need to bend, because space suits are not very flexible and so are robots, which makes placed of the sensors on the arm a smart idea after all.

Blast in all its Glory!

 

For some extra Fun, we wanted to create a remote control program. We hooked the PlayStation 5 controller via Bluetooth to the iPad and create a program to control the robot with the gamepad.
There is a nice intro video on how to connect a gamepad with an iPad. Quick and easy, but there is a little issue after a while when the robot or iPad goes into sleep mode the Bluetooth disconnects. 

Tip: 

When trying to use the remote control again the gamepad does not seems to work. Even if the app says the gamepad is connected. The solution is just to press the PlayStation button and share button of the controller for 3 seconds to synchronize it again and the app reacts to the controls of the gamepad again.

The scratch program we created uses the left stick to move forwards and the right stick to turn. I added extra controls for the L/R button to lift or lower the arms, which makes it possible to aim the shooting darts.

First, click and add a button in lower left corner to add all extra program functions including the blocks for the PlayStation controller.

Here is a little rundown of the program:

 

movement controls

-"when the program starts" needs to be always there

- Blast calibrate is first. It makes sure all parts are synced.

- added the start sounds command “hello”

- added Forever block, its an endless loop that runs all the time
- added blast movement controls for the blast robot inside the forever block

now we replacing the "0" and "50" with 2 control block from the PlayStation command section

- On top of the "x" we added one block,  set it to "right" and "x-axis"

- On top of the "y" we added one block, set it to "leftt" and "y-axis"

This makes the robot move via the gamepad. We've already build the Blaster aka Darts shooting extension for right arm.

So we can just right into the dart shooting program :

blaster controls

- We added the event block trigger but the cross "x" button
- The "blast action" block is premade command from Lego to shot of the laser
- Next play laser is a sound command
- Set trigger motor in a neutral position to release the spring inside the shooting module, Another wise we could not load the dart 

arm control 1

 Next, we set up the movement for the arm:
- Gamepad control block which has the R2 button as a trigger option to lift the arm
- Adding the motor control button and set motor D to rotate 80 degress at 120% speed
 

 

arm control 2

- a copy prevous 2 block which is Set to the L2 button

- motor control button and set negative rotation, which lowers the arm

 

The program is done and we are ready to try out the remote control program.

robot and gamepad conntected

 

Once the hub is connected you press play, and the app tell you to switch to stream mode. The stream is consistently connecting to the iPad and the iPad is connected to the gamepad. This means the iPad gets the impulses commands from the gamepad, run through the program it and gives the commands from the program to the robot (hub unit). It’s a live connect of all devices.

Controlling the robot with the PlayStation controller was super fun, we had a blast!

 

 

 

 

 

 

We had sometimes disconnections or the robot was stuck in one movement, it was fixable after disconnecting and reconnecting to the robot with the iPad. Maybe it's an IOS Bluetooth issues. Or maybe the screen sleep mode timer was too aggressive. We replaced the iPad with my MacBook. This combination seems to work much better.  It’s better anyway to have a computer connected, which makes the program of the robot much easier with a mouse and proper keyboard.

the battery life was about 1 hour. If wanna have remote-controlled vehicles, a dedicated RV car or robot will be better suit for long intense remote play. Robots are meant to run programs, experimental play and learn etc.. but it’s nice to be able to have some remote-control fun. 

 

the whole program :

complete remote controls program

Starting with the Mindstorm Inventor Set 51515

Recently the Lego Mindstorms Robot caught my eye when I was looking for educational Activities for my son. The new Inventor 51515 sets seem ideal for a father and son Projekt. I also look into the SunFounder Robotics Car sets, which are mechanically builts and use Raspberry Pi computers as the main control system. This will gives more options in terms of programming with Python, I've could go nuts with PyTorch on a fast ARM mini-computer system like Raspberry Pi. but it will take too much effort and time. It would be too advanced for the beginning, that's why I choose for the Lego system.

 

showcase of all 5 default robots you can build out of the box

 

Robots, quadruped, remote control, Scratch and Python support etc. , all in a neat package which does not seem too complex. Here is whats Wikipedia says about Mindstorms :

Lego Mindstorms is a hardware and software structure which develops programmable robots based on Lego building blocks. Each version includes computer Lego bricks, a set of modular sensors and motors, and Lego parts from the Technic line to create the mechanical systems

The MindStorms is a re-packaged version of the lego spike system as a commercial version for everybody. the lego Spike system is from Lego Education, which special branch to bringing Lego-supported education into Schools. 

 

My son, 9 years at the time, might be a little too young for this, but exposing him early might be beneficial, I could go with a lego Boost Robot from Lego, but it would be less interesting for both of us. the inventor set comes with 5 possible builds out of the box.

• Blast – this master robot is a stoic action hero. It can fire or hammer its way through obstacles and grab items. Builders can be the ultimate commanders, programming it to scan its environment and fire darts if it senses danger. Perfect for guarding your room!
• Charlie – this quirky sidekick helper can give out high fives, dance, play the drums, deliver small gifts, and charm friends with its smile.
• Tricky – the sporty bot is the ultimate athlete. Code it to complete the perfect slam dunk or master a plethora of robot sports: basketball, bowling or soccer – the list goes on and on.
• Gelo – a real life four-legged robot. Its unique mechanism means it can walk, avoid obstacles, and even perform tricks.
• M.V.P. – The Modular Vehicle Platform gets the job done. Create and code your own remote control and build the M.V.P. into a buggy, a crane, a shooter turret or even a brick-eating truck to pick up LEGO bricks left by the other robots.

plus more than a dozen of official custom user build to download and try all inside the app: 

offical approved community project, ready to build.

 

The Set does come without any printed Manual or instructions book, instead, you download the App for Windows, Mac, Android or IOS (sorry no Linux). at first sight, it's odd not to have a printed construction manual after 2nd thought it makes sense. There are so many different combinations of building sets and a printed Manual would massive and confusing. 

The app does very good job to make the experience more interactive. for example, after complete parts of the model, the apps offer the software/program to test already finished robots arms or provide a short video for extra help (like how to connect your hub with Bluetooth etc.,). 

It has also the benefits to update the content with lastest software improvements etc. The in-app Help features are also very helpful and contain short explainer videos.

 

in-app assemble instructions

There is also PyBrick and open-source micro python API, which claim to run faster than the original lego python Api. The Inventor kit is in beta and incomplete, too risky for now to mess up the whole system.

but there is more, there is a sound editor, animation editor for the Display, possibility to connect Xbox or Playstation Controller and even basic Machine Learning routines, I assume it has to be streamed via Bluetooth to the hub unit because I don't think the hub would be powerful enough. I definitely wanna try it out later on.

since there are only very few Tutorials about the Lego Inventor Set, 1 or 2 Youtube channels and 2-3 blogs with great builds but with only a few much in-depth information.
That's why I decided to create this blog to document my journey with the system.