Assembling instructions (mini_V0)

Understand the pinouts of each component in the kit. Understand how they are connected in the block diagram and in reality. Later you may change the configuration, however the corresponding pin numbers in code should also be updated.

Circuit

1. Solder the PCA9685 servo board. Note that only the capacitor and the middle two 3 x 4 pin blocks are used. Pay attention to the sign of the lead on the board and the capacitor. If you're not sure, search the wiki for polarized capacitors.

The back side of the soldered board.

The front side of the soldered board.

2. Solder the MPU6050 board to the PCA9685 board. They are connected through I²C interface. Link their Vcc, GND, SDA, SCL, pins with ribbon cables. Later, the INT pin on MPU6050 will be linked to pin 2 of the Arduino Pro mini. Follow the board's direction and the wiring order shown in the picture.

3. Solder the infrared receiver to Arduino Pro mini. Recognize its pin names in the following picture.

The signal pin should be soldered to pin 5 of Arduino. Vcc and GND should be soldered to the same side with Vcc pin. After soldering, bend the IR receiver so that its face is exposed outward. Make sure the three pins are well separated.

Solder the buzzer and the INT wire of MPU6050 before or after soldering on the IR receiver. Again, pay attention to the positive and negative sign on the buzzer. Its positive should go into pin 4 on Arduino.

4. Solder the Arduino Pro mini to PCA9685 board. They are connected through I²C interface. Link their Vcc, GND, SDA(A4), SCL(A5) pins with ribbon cables. Depending on the version of Arduino Pro mini（or other micro-controller boards), the pin definition and location of SDA and SCL may vary. Also notice that the VCC and GND have been occupied by the IR receiver, so you may solder the wires on its exposed pin legs.

Connect the V+ pin on PCA9685 to the Raw pin on Arduino and solder. There're two V+ pins on the PCA9685. Use the side shown in the following image.

5. Solder on the power supply. The positive wire from battery pack will go through a slide switch, then connect to the other V+ on the PCA9685.

Now the circuit part of CatMini is done! Double check with the block diagram to make sure every connection is correct.

6. Install the circuit on to the frame. There are several types of screws used in the kit. Compare and recognize their actual sizes.
   

Arrange the circuit boards on the frame with the following orientation. Use self-tapping screws to fix them to the frame.

Cut excessive pin legs and lay the Arduino flat on the frame. Push the board into the slot and fix it with screws on the side. Screw in the MPU6050 next to it.

7. Install the battery holder to the frame.

Side view of the control module.

Body Frame

8. You could print all the body frames using the STL files. However, I recommend print one piece of each component, screw in the holes, and use it as a punch to duplicate wooden pieces.

9. Most of the body frame will be fixed by screw Sa. Assemble the wooden pieces and the servo holders in the following manner.

Side view. Notice that not all screws are fulling screwed in.

10. Install knee servos. Let the servo's wire go through the hole on the servo holder.

Fix the servos with screws.

Direction matters. Install the four knee servos in the following pattern.

11. Install the shoulder servos.

12. Prepare the four thighs.

You'll need eight 9/32"(OD) x 3/4"(length) compression springs.

Cut the cross servo arm according to the image below. Insert the longer side, then press the shorter side into the track of the thigh. Make sure it can slide freely in the track. You may drop some lubricant in the track before hand. Install the spring to keep the servo arm in the structure. Be careful that the spring may jump around and hard to find.

There are eight installations for four legs.

13. Attach the knee servos to the thighs, but don't screw yet.

Attach the thighs to the shoulder, but don't screw yet. It just gives you a feeling how the limbs are connected.

Side view.

Bottom view.

14. Take off the thighs. Wrap the shoulder servo coils in the following pattern.

Top view.

Install the covering wooden sticks so that the coils are fixed in place.

Side view.

15. Attach the control module to the wooden frame. Plug in the shoulder servos to PCA9865. Be CAREFUL with the directions and locations of plugs. The color code for servo wires is: brown (GND), red (V+), yellow (signal).

16. Attach the thighs to the shoulder. Wrap the knee servo coils in the following pattern.

Top view. The last one or two coils is used to fix the wire to the frame. Plug in the knee servos to PCA9865. Be CAREFUL with the directions and locations of plugs.

There's a lookup table in the scratch code (writeConst.ino) for the mapping between servo indexes and pin numbers on PCA9685:

byte pins[] = {0, 0, 0, 0, 0, 0, 0, 0, 5, 4, 10, 11, 7, 6,8, 9};

Servo indexes 0~7 are reserved for more advanced model.

Servo Index	PIN # on PCA9685
8	5
9	4
10	10
11	11
12	7
13	6
14	8
15	9

Servo 14 is hidden in the above picture.

17. After finishing the whole installation process, you may glue the slide switch to the battery holder.