Saturday, March 1, 2008

B9 Electronics: The Inside Story Part 5 - Radar Section

My radar section uses the B9 creations' 2.5v regulated power supply and the Namiki Ear Motors for the ear sensors. Both of which were obtained from Eric Johnson from the club website. The Namiki motors are very sensitive to voltage and you can burn them out easily. The radar is moved by a digital robotic high power JR servo (JR DS8711). The range of movement is 180 degrees. 90 to the left and 90 to the right. I can fit a 360 degree servo in there or I could use a sailing wench servo for continuous rotation but most shots from the series do not show the radar moving greater than 90 degrees because the rotation of the radar section was controlled by Bob Mays head movement, so I decided to stick with that. I would suggest that you use a geared motor to rotate the radar section if you want to have 360 degree movement. However, in order to do that you would need to have a motor controller to be able to direct the degree and direction of rotation. That just means more money and more stuff to cram into the collar/radar area.
I also experimented with IR (infrared) sensors in the collar to direct movement of the radar when the robot is in animatronic mode to further simulate AI (artificial intelligence). The device I used was from Jim Shima's website called Hyperdyne and These are the same controller cards that the R2D2 group uses for automatic dome rotation in relation to sound and IR movement detection. It works most of the time so long as you are not in a very loud or hot room. That is not always possible at a convention. Also, since the detectors are in the collar you have to be at least 48" tall for it to detect you. So what I decided to do was put in a IR detector in the rear vent bay to detect those pesky little carbon based replacements we call children. When it detects someone close it triggers a voice message saying to please stand clear and to step away from the rear vent and power pack.

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