About - LEGO Mindstorms Junkbots: "The idea behind the LEGO Mindstorms Junkbots is to bring together the motors of the LEGO and use them to power the robot which is otherwise created from junk. The key aims of the project are;
To give children at a KS2 primary school level an insight into what can be achieved through the use of simple programming.
To provide a fun and engaging activity for children to be creative and design their own robots.
To use the robots and programming software to achieve basic movements of the Junkbots.
The original junkbots project combined the idea of using motors and vibrations to move the bots with limited control however the new project uses the idea of programming to add a further element of control and as such the simplicity of the self contained NXT device was decided upon as a branch of this.
Aiming the project at KS1 and KS2 gives the opportunity to introduce basic programming from a young age and demonstrate just one of the interesting possibilities that comes from it."
Raspberry Pi Junkbot - Home: A new website providing more information of the Raspberry Pi Junkbot project (combining Raspberry Pi, Scratch programming and junk). This will be added to as the project develops.
Choice of interface/Controller card The card choosen was the 4Tronix PiRoCon card (http://4tronix.co.uk/store/index.php?rt=product/product&product_id=182). Selected for four reasons - Price is reasonable (in my opinion). - Fits straight onto the Pi through the GPIO - no extra cables needed. - ScratchGPIO has it as an addon so it makes programming it even easier (see http://cymplecy.wordpress.com/2013/10/31/pirocon-from-4tronix/). - Others are using it for robot projects. Use it is quite easy plug the board directly on to the GPIO connector of the Raspberry Pi (4tronix provide some advice in section 15 of http://4tronix.co.uk/blog/?p=22 on mounting the board). The only other changes I needed to make because I wasn't powering the motors through the DC input I had to change the jumper settings next to Vin Connector (see http://4tronix.co.uk/blog/?p=41 for layout) to reflect this. Example Now for the fun bit get the whole thing to draw (see Figure 1 and the video at the end)!
The junkbot itself is made up of a drinks can, three supports (we used LEGO here but it equally could be straws, sticks), a pen/pencil, and a motor and broken propeller combination to create an unbalanced motor. With the Raspberry Pi off, the the motor's wires are connected to the controller card at the connections for MotorA and the battery is also connected. Turn the Pi on and run ScratchGPIO5plus.
The first task is to make the variables AddOn (which will be used to tell the program we are using the PiRoCon card) and MotorA for the motor (see Figure 3). In Figure 4 the program can be seen, essentially the left and right key spin the junkbot clockwise or anticlockwise by setting the Motor to either +ve or -ve values from 0 to 100. The space bar is used to stop the motor. As it moves because one of the supports is a pen it draws. See the video below to watch it draw a squiggly line - control is still a challenge. The bot was developed by Hayden Tetley and Scott Turner. Hayden's time was paid for through the Nuffield Research Placements Scheme (http://www.nuffieldfoundation.org/nuffield-research-placements).
If you would like to know more about the Junkbots project contact email@example.com. The views and opinions is the authors and should not be taken as representing the views of any organisation the author is associated with.
A development I have being wanting to develop for a while is the combine the Raspberry Pi with a Junkbot to add some control. This the first of postings about these experiments. All the development will be around ScratchGPIO (http://cymplecy.wordpress.com/scratchgpio/) so this posting will look into its use. Why ScratchGPIO? Short answer - simplicity. It is designed to look and work like Scratch (http://scratch.mit.edu/) but allowing access to board that can drive motors. Installing ScratchGPIO? As a suggest use as lastest as possible version of the operating system as you can on your SD card. Initially we had trouble with missing Python files that was resolved when using an updated version of the operating system. In the LXTerminal Type in: sudo wget http://goo.gl/Pthh62 -O isgh5.sh then type in sudo bash isgh5.sh You should get to new icons for ScratchGPIO5 and ScratchGPIO5Plus Now use these instead of the Scratch that came with the operating system.