Pendulum Video
d. bodnar  rev 11-24-09

Click here for the Pendulum Construction Article

New Video!

The video below shows a Playmobil character that performs as an acrobat.  This animation will be installed at Pittsburgh's Children's Hospital where the PGRS has designed and installed a train display

Since the animations at Children's are started when a child presses a button the pendulum must "self-start".   Experimentation found that the key to the self starting is to deliver several pulses of 12 volts to the pendulum circuit.

The pendulum is controlled by a PIC microcontroller that varies the voltage that is delivered to the normal pendulum circuit.  The PIC delivers a string of pulses so that it self starts, lowers the voltage so that the acrobat swings gently then increases the voltage so that she does 360's for several seconds before resting and coming to a stop.

(right click box below and select "play")



First prototype
(right click box below and select "play")

Second unit
Shorter arm and more turns on coil.
(right click box below and select "play")

Possible Animation for Upcoming Garden Railroad Circus Event
(right click box below and select "play")

Videos of Two Acrobats at PGRS Layout in Canonsburg, PA - 9-18-->20, 2009
(right click box below and select "play")
Note that the acrobat on the left does a 360 from time-to time depending on wind and position
The swing set is animated with a PICAXE circuit and a servo.


Another shot from the same angle
(right click box below and select "play")

Another shot from another angle
(right click box below and select "play")
Again the one acrobat does 360 from time-to-time


The clip at the top stops oscillation - will experiment with capacitors (5 pf from base of Q1 to ground?)