Animated Mannequin Attracts Attention

    Businesses hire people to wave a sign out by the side of the road to
catch the motorists' eye and point them toward their business. But a beautiful
animated mannequin also catches the motorist's eye plus turns a lot of heads.
The mannequin before modification.
   This mannequin was selected for the pose, the joints required for animation
and facial expression.  The arm joint will be covered by a halter top and the
neck joint will be covered by a stretch band.
Another good mannequin to use.
   We found only two mannequins that would work right and were smiling.
The arm flange parts.
   The right arm is the one that will wave and so the mounting tongue was
broken out and disassembled.  The steel disk will be epoxied back after the
drive shaft is welded to it.  The right hand will be screwed into the arm, but
turned 180 degrees to face outward.
Some mannequin modifications.
   The head was cut from the torso on a horizontal plane.   The arm mounting
socket has had a hole cut into it for a flanged ball bearing.  The torso
centering cone has been drilled for the wires that will come up from below.
Some suitable gearmotors and a power supply.
   These gearmotors can handle 24 volts but run best for our needs at 6 volts.
The Merkle-Korff 91055A on the left will be used for the head animation.  The
Japan Servo Co. DME60A26 on a 6H9F gearbox in the middle will operate the arm.
   There are two ways to animate a mannequin.  Gearmotor shafts can rotate
continuously while an arm on the shaft is linked to an arm on the animation
shaft.  The advantage of this is cost and simplicity.  Speed is determined by
the voltage sent to the gearmotor.  The swing is set by the crank arm radius.
But this method requires finding gearmotors with the right power and speed.
   The other option is to use strong robotic/industrial servos and control
each one with a microcontroller.  This is the simplest-to-assemble and most
versatile way, but also the most expensive.
The internal mechanics in motion.
   This shows the first method, continuous rotation by two gearmotors.
The mannequin in motion.
   The stand houses the power supplies and has wheels for moving the assembly
when the stand is tilted by a removeable handle. The angle-iron brace is where
the business's sign would be.
   Each servo can be controlled by a BASICStamp Homework Board microcontroller
from Radio Shack. (The box is labelled Experiment Board.)  The signal from the
output pin of the microcontroller goes to the signal input wire of the servo.
The red servo wire goes to the red (+) cable of the power supply.  The black
servo wire and the microcontroller's ground wire go to the ground (-) cable of
the power supply.
A strong industrial servo suitable for the arm.
   This Tonegawa-Seiko servo has 27 ft-lbs of torque, but costs $670.
A smaller Tonegawa-Seiko industrial servo.
   These cost $280 and can operate the head.  But any "1/4 scale" model plane
or sail winch servo with 400 oz.-in. (2 ft.-lbs.) of torque would also work.
   A servo can be programmed to operate at any speed and amount of swing by
the microcontroller.  Each BASICStamp microcontroller also requires 9 volts.
   This program moves two servos at the same amount of swing and rate so that
they move in unison.  You can customize the parameters 200, 1200 and 50.

Program:                     !  Explanation: (not necessary for operation)
' {$STAMP BS2}               !  (click on green Stamp icon)
' {$PBASIC 2.5}              !  (click on 2.5 BASIC icon)
x VAR Word                   !  set variable x for two bytes
forward:                     !  200 is full swing one way, 1200 is full swing
FOR x = 200 to 1200 STEP 50  !     the other way and 50 sets the swing speed
PULSOUT 1,x                  !  send pulse x to output pin 1
PAUSE 20                     !  hold pulse for 20 ms
PULSOUT 2,x                  !  send pulse x to output pin 2
PAUSE 20                     !  hold pulse for 20 ms
IF x > 1200 THEN back        !  if at full swing, move in the other direction
NEXT                         !
back:                        !
FOR x = 1200 to 200 STEP 50  !  (not -50)
PULSOUT 1,x                  !
PAUSE 20                     !
PULSOUT 2,x                  !
PAUSE 20                     !
IF x < 200 THEN startovr     !
NEXT                         !
startovr:                    !
GOTO forward                 !
   To swing each servo at different speeds and swings SMOOTHLY, it is
necessary for each servo to have its own microcontroller. (A program that
operated two servo gearmotors at different speeds and swings was too jerky.)
You can customize the parameters 200, 1200 and 30.

' {$STAMP BS2}
' {$PBASIC 2.5}

x VAR Word

FOR x = 200 to 1200 STEP 30      (200 to 1200 is the swing, 30 is the speed)
PULSOUT 1,x                      (pin 1 is the signal-out pin in this case)
IF x > 1200 THEN back

FOR x = 1200 to 200 STEP 30
IF x < 200 THEN startovr

GOTO forward

   When putting the program into the BASIC Stamp, it must be connected to a
computer by USB cable.  But after the program is in, it is only necessary to
power it up to start the animation and turn it off to stop.  Then turn off the
servos' power supplies.
                     MAKING INDUSTRIAL SERVOS
   If you are competent with electronics, you can make very strong servos
using any gearmotor.  It requires taking a model plane servo apart and using
its circuitry to drive stronger gearmotors.
(See the RADIO-CONTROL GASOLINE LAWNMOWERS page for more detail.)
   The motor inside the model servo must be removed and five wires must be
added to go to an external circuit called and H-bridge which powers the strong
gearmotor. The microcontroller sends its signal to the model plane servo. The
model plane servo sends its signal to the H-bridge.  The H-bridge sends power
to the gearmotor with polarity to turn either clockwise or counterclockwise.
An external potentiometer connected to the gearmotor's shaft tells the servo
electronics the position of the shaft.
The wiring for a power-gearmotor servo.
This gearmotor makes a very strong servo.
   The servo output arm is far left.  A string "belt" goes from the shaft of
the gearmotor to the black knob on the potentiometer.  To the right of the
black knob is the servo's circuit board. (Since this was used to steer
a radio-control lawn mower, it still has the receiver cord on it, not the
wires to go to the BASICStamp pins.)  Far right is a rechargeable 7.2 volt
battery from a power screwdriver.  Above the battery is the H-bridge circuit.