Portland Area Robotics Society

Regular Meeting Minutes

May 6, 2006, 10:30AM



1.      Welcome and Announcements

2.      May Enthusiast Event

3.      Presentations:

a.       Dave Shinsel: Compensating for compass tilt and Robonova-1 demo.

4.      News Reports

a.       Show-and-tell


1.      BotFest %G–%@ May 20 2006.


BotFest Enthusiast Event (Roger Ray)

Botfest is May 20 2006. Announcement posted to PortlandRobotics Yahoo group. See also portlandrobotics.org.


Robomagellan in the morning. Indoor event in the Gym in the afternoon.


Need more volunteers for Leads and Helpers for various events. Participants will take turns judging events. Contact Roger Ray to volunteer. Subscribe to the PartsEvents Yahoo group.


Next planning meeting is Thursday 7PM.


This is an enthusiasts event %G–%@ the goal is to have fun and socialize with other robot enthusiasts. Feel free to bring bots in various states of functionality %G–%@ share and learn!


Dave Shinsel: Compensating for tilt with electronic compass + Robonova-1 demo

Dave is using a compass made by Devantech. He has worked on compensating for the tilt sensitivity of this compass module.


The heading of the robot and the direction of slope of a hill both affect the read-out of the compass. When heading North, cross-slope has little effect. When heading east-west, a north-south slope has a magnified effect. In some cases, Dave measured errors of 40-50 degrees.


Plot of heading errors versus slope direction looks roughly sinusoidial. Dave is developing algorithms for compensating for error.


Dave is now using an accelerometer to measure the tilt of the robot.


Current status %G–%@ now getting about 20 degree errors. He plans to route his RoboMagellan robot to avoid the most serious compass errors.


Dave also demonstrated his Robonova-1 humanoid. He has added a sonar sensor and an accelerometer to this robot. He has also added a Bluetooth module for remote control. Dave demonstrated a choreographed dance routine. The Robonova-1 is controlled with RoboBasic, which allows poses to be programmed manually. Intermediate motions are calculated automatically.


Other members recommend AKM Semiconductors magnetic compass.


Show-and-Tell and News

The new Darpa Grand Challenge has been announced. It will recreate an urban environment.


Rocko demonstrated progress on his Shake robot. The head now has sensors for obstacle detection.


Mike (SurplusGizmos.com) has some wireless touch-screen computers for sale.


Paul brought in a couple of microsumo bots and a BEAM walker. These are based on gears taken from surplus 1/3 rpm gear motors.


Martin is working on a 4-wheel holonomic robot. Wheels are from Lynxmotion ($10 ea). The body is bent aluminum. Control electronics are in-progress. He hopes to turn this into a line-follower.


Larry purchased a couple of the Parallax Propeller microcontrollers. These have 8 32bit processors. Programming is in assembly or the Parallax Spin language. There is a USB downloader, or serial programming is possible. Program storage is on an external I2C memory chip.


Tim is working with a compass module made by PNI.