Facehugger

(Instructions @ https://www.thingiverse.com/thing:1116392)

1. Print
2. Superglue the pieces together to form each segment
3. Assemble by snapping joints into place
4. Coat with liquid latex
5. Paint using acrylic paints
6. Mount clock mechanism in bottom of Facehugger
7. Mount onto face

Chestburster

(Instructions @ https://www.thingiverse.com/thing:1396909)

1. Print
2. Coat with liquid latex
3. Paint using acrylic paint
4. Mount onto linear motion mechanism

Linear Motion Mechanism

1. Print mechanism components from here using Chestburster3.scad
2. Assemble based on render in Chestburster3.scad
   1. Mount motors in central carriage using M3 screws
   2. Place racks in rack end pieces
   1. Place carriage inside rack assembly
   2. Mount pinions to motor shafts
   3. Place 1/2" dowel in carriage
3. Mount Chestburster onto dowel

Mannequin

1. Paint foam head with skin tone spray paint
2. Duct tape cast body for mannequin body (http://www.instructables.com/id/How-to-Make-a-Mannequin-with-Your-Measurements/)
   1. Note: Do not suck in!
3. Place head in neck hole in body cast and duct tape into place
4. Iron Nostromo and Weyland-Yutani patches onto white t-shirt
5. Put t-shirt on mannequin
6. Attach wig
7. Stuff shoulders with spare pillow, cotton stuffing, or newspaper
8. Cut a large hole in mannequin sternum
9. Cut a small hole in back for USB cable
10. Cut a "Y" in the t-shirt over the chest hole

Electronics

1. Wire Arduino or Redboard to DS1307 (I2C pins)
2. Attach pins 5 and 6 to the L9110S motor controller A_IB and A_IA pins, respectively
3. Wire the Motor A connector to the two motors (in parallel) from the linear motion mechanism
4. Attach a speaker form pin 11 to GND
5. Load this sketch onto the Arduino

Final Assembly

1. Trace the base of the mannequin onto a foam-core or cardboard sheet
2. Cut out the base
3. Mount Chestburster using stacked cardboard, foam-core, or other thick sheet to achieve necessary height to align with chest hole and attach to base
4. Place the mannequin body over the base assembly and secure into place
5. Power on the clock and enjoy!