April 14, 2012

Meeting Date: 
Saturday, April 14, 2012

Stephen C.

Class : Introduction to Parallax Propeller

The Parallax Propeller chip has 8 cores, named cogs. They each run independently, and can turn IO on and off (note this can cause contention, although there are locks that can be used). Each cog has its own memory known as “cog memory”, and there is also common memory that can be accessed by all cogs. It can be run at frequencies from 5 – 80 MHz. There are two programming languages, Assembly and Spin. The Spin language uses whitespace for structure, similar to Python.

Stephen covered the some basics of the Spin language, including syntax, structure, and functions. He then demoed some code and hardware of a joystick controller servo. Next, he showed some code running on a demo board that outputs VGA graphics, all on a single cog! He also showed some of the more advanced debug features in the software, such as the oscilloscope feature.


There was mention of a great book that covers a balancing robot, OpenCV, and other projects : Programming and Customizing the Multicore Propeller Microcontroller: The Official Guide (Amazon Link)


For much more information, see the Parallax website : Parallax Propeller

You can also check out the manual here : Parallax Propeller Manual (4.7MB)

There are also some great examples (including an overview of the DanceBot which can balance itself) at this website : HannoWare



Business Meeting


Old / New Business

Treasury Report : A total of 18 members donated optional dues of $10. If you would like to donate please talk to Ron.

Group Robot : If you would like to borrow the group robot to learn or experiment with it (and not break it) you are free to do so. There will be a deposit required to make sure the robot comes back.

Bulk Robot Part Ordering Website : Peter gauged interest, which there was a great deal of, in creating a website that members could submit parts that are looking for, contribute possible vendors, as well as price breakpoints and how many they would like to order. This would allow us to get great deals as a group, by ordering bulk and also by dividing up the shipping costs. A great idea!

IWAH Trophy : No winner this month, although it was close.



VEX Robotics World Championship : The competition is coming up on April 20 - 21 in Anaheim. Free admission for some people (check the PDF for details here )

Mini-Urban Challenge : This is a high school competition to create a robotic car that drives in a model city. It appears the LA regional competition for this year is already done, but the final is coming up in DC in May. Those interested in starting a team should check out this website ( link )

RoboGames : Coming up next week in the Bay Area! Check it out if you can! ( link )

LA Robotics Club : This club has many meetings on a variety of topics. You are strongly encouraged to check out their website (or join!) and see what events may be coming up in our area ( link )

Tri-Club Competition : Thomas is working on setting up a competition between RSSC, the Riverside Robotics Society, and LA Robotics Club. No details are yet available.

Riverside Robot Expo : This year it will be on November 3rd (tentative?). Please contact Thomas if you have anything that you would like to show. Also, any contacts that you have in academia or industry who are involved with robotics, we would love for you to try to get them involved!

Riverside Robotics Club Arduino Class : Thomas announced that thanks to donations of parts and laptops, that Arduino kits (including servos, LED's and other goodies, as well as a laptop) will be borrowed out to students for educational endeavors.


Upcoming Classes (11:00 – 12:00)

Month Class Presenter
May 12   Introduction to Arduino     Thomas 
June 9   Botluck : Group discussion of projects (no class)    


Upcoming Competetions:

June - Hallway contest

Choose your method of dead reckoning, wall following, odometry, etc. No landmarks may be added to the hallway. Alex will update with additional rules in the future.

July - Bipedal robot competition

Gene will put together some guidelines based on the RoboGames (http://robogames.net/rules/biped.php). Maybe also have a freestyle competition.

December - Annual Robot Talent Show



Show and Tell


Dr. Bruce

This week Dr. Bruce talked about the brains for Leaf 2.0. It's an HP laptop with i5, 6GB RAM, and 500GB hard drive. He's working on getting Ubuntu to dual-boot and ran into some problems with the Wubi installer. He discussed using the VMWare Player on Windows and running Ubuntu with ROS on the VM. However, as several members pointed out this could cause complications due to the USB/Driver passthrough for Kinect. Updates will come at the next meeting.



Parallax has a "Process Control" parts kit that he's been investigating. Also, he obtained a BOE-Bot with Arduino Shield from Parallax for evaluation (and we are all jealous). Several tutorials on this new platform are readily available at http://learn.parallax.com/ShieldRobot




Phil gave a brief overview of his experience on the CS101 course from Udacity. Udacity has several free courses, including the "Programming a Robotic Car" class. Signup for new classes is already beginning! Check out their site here ( Udacity link )

Secretary's Note:
There are also many new courses starting at Coursera ( Coursera link ) covering a variety of topics, mostly computer science related. Also members may want to keep an eye on MITx ( MITx link ) for new classes coming up. They offered a circuits and electronics class in the spring.



John showed an LED cube (3 x 3 x 3) controlled by an Arduino. He is using a clever scheme to control all 27 LED's with 12 IO pins by wiring a column of 3 LED's together, making 9 vertical columns (in a 3 x 3 grid). The vertical columns are controlled with 9 pins. The grounds are all bussed together in a plane, and controlled by another 3 pins, allowing addressing of a single LED through a plane/column. I found a link that describes a similar project here ( Instructables link )

He plans to replace the "expensive" Arduino board with a TI MSP430 LaunchPad that costs a mere $4.30 ! You can pick these up from DigiKey ( DigiKey link ) or check your favorite electronics distributor. Texas Instruments has more information, a video, and description of some projects including a 2-wheel robot ( TI MSP430 link )




First, Thomas discussed his project to make a home-built servo, instead of spending $700 on a high power servo. For example, you could use a board to control a windshield wiper motor (5 ft-lb).

He found the BabyBully circuit board that will allow you to control a generic motor at up to 15 Amps for $80 - 85. ( BabyBully link ). Another member mentioned that Pololu sells some nice boards with similar functionality, with a 3A option for $50.( Pololu JRK Controller )

Next, he discussed the EZ-Robot board ( EZ-Robot ). This board has an amazing amount of features for a relatively low price, including speech recognition and synthesis, face and pattern recognition, and tons more. He even demoed the board, showing how he could control servos with speech, get the robot to follow a face, and give interesting spoken responses with NO PROGRAMMING!




Maya showed a robot ostrich that she built. It was a rather impressive little biped that worked great! And it only took a few nights for her to complete. Nice work!



Tim showed how the Wii Nunchuck can be used with the Arduino to control a servo using the accelerometer. I was able to track down the PDF that Tim showed snippets of, based on sheer luck of keywords. This presentation goes through Arduino, servos, and the nunchuck in a good amount of detail for those who would like to follow along ( Arduino Nunchuck PDF (6.6MB) ).