(1) hobby servo motor with “Servo Horn”
(Solarbotics Part #GM4)
(1) 1.5 inch (4cm) plastic gear (around 40 teeth are good)
(1) 2 feet of 8 to 10–gauge wire; can use coat hanger wire or 10-guage copper wire (Solarbotics Part #Wleg)
(1) short piece of 1cm diameter plastic tubing (can use “jacket” from preceding leg wire)
(1) terminal block (Radio Shack Part #274-678)
(2) AAA battery holders (each holds two AAA batteries)
(1) length of 1cm diameter heat-shrink tubing (can use “jacket” from preceding leg wire)
(2) .22 µF monolithic capacitors
(1) 100K to 10MΩ resistor (we recommend 3.2MΩ)
(1) 74HCT240 integrated circuit (IC)
(1) on/off toggle switch (smallest you can find)
(2) leg mounting pads (Solarbotics Part #LMP2); optional, but recommended
pieces of scrap plastic (from product packaging) or .030" plastic sheeting
several feet of stripped hook-up wire (or other 22-guage wire) 
clipped from: www.streettech.com