The servos could be given to you in a any state or you could have moved them accidentally so it's best to position the servos while they're in 'home' position and so you know that they're not going to run into anything when they're moving.
Make sure the glue has dried for the base servos and the top servos. I like to shave off the excess gorilla glue that comes out. When you've made sure the glue has dried, mount the base servos onto the headband. Connect the top servos to the base servo's arm. Connect all the servos to the circuit board, making sure to get the position correct.
Depending on your servo, there will be different colors indicating which line out is power, which one is ground and which one is signal. servodatabase.com (http://www.servodatabase.com/
) has a lot of information about the servos commonly encountered, including the HXT900 (http://www.servodatabase.com/servo/hextronik/hxt900
) and the TG9e(http://www.servodatabase.com/servo/turnigy/tg9e
). A useful resource I found was here(http://www.societyofrobots.com/actuators_servos.shtml
) where they give some common colors and their meaning:
All servos have three wires:
Black or Brown is for ground.
Red is for power (~4.8-6V).
Yellow, Orange, or White is the signal wire (3-5V).
The programmed ATTiny13 expects the following arrangement (all positions as if we were wearing the kitty ears):
pin 5 (PB0) - bottom right
pin 2 (PB3) - top right
pin 6 (PB1) - bottom left
pin 7 (PB2) - top left
The datasheet for the ATTiny13 can be found here(http://www.atmel.com/Images/doc2535.pdf
Once everything's connected, power on the circuit by attaching the battery to the regulator and the regulator to the circuit. While the circuit is on, position each of the servos so that they rest in the desired home position. The base servos should be facing forward and the top servos should have the acrylic in the same plane as your face.
Once they've been positioned, run through each of the preset motions to make sure they can move with the full range of motion without hitting the headband, the armiture or the other servos. This also serves as a final test to make sure the circuit is working properly and gives you the opportunity to debug anything that might have gone wrong up till this point.
The preset motions are as follows:
Press and hold - "Surprise"
Tap then press and hold - "Angry/Sad"
Tap three times - "Ear wink"
You might need to grind down the metal armiture around the edges where it's close to the top servos attached acrylic.
If the top servos motion hits the base servo during one of the preset motions, reposition the top servo forward a bit more so that its full range of backward motion is allowed.
Once the servos have been positioned, turn off the servo by disconnecting the regulator from the circuit.