Otto DIY++ is a redesign of the Otto DIY PLUS (https://github.com/OttoDIY/PLUS).
With this 3D model, you have room for: bluetooth module, metal gear servo (MG90S), Led matrix mouth, rechargeable battery, light sensor, touch sensor, etc.
And some bonus conveniences: can use remaining screws in servo pack to fix arduino board and power switch.

I. List of parts:

1. Arduino Nano + USB A to Mini-B cable
2. Arduino Nano Shield I/O Extension Board
3. HC-SR04 Ultrasound sensor.
4. Mini servo MG90S x4 (each one comes with 2 pointed screws and one small screw)
5. 5V passive Buzzer.
6. Female to Female breadboard connectors cable
7. 8.5x8.5mm self-locking Switch.
8. HC-06 Bluetooth module
9. MAX7219 LED Matrix module (SDM)
10. Sound sensor (using LM393) with Analog output
11. Light sensor (using LM393) with Analog output
12. YFRobot touch sensor
13. Rechargeable Battery with separate charging and discharging wires + balance charger
    Mini cross screwdriver. (magnetized)

II. 3d printing plastic parts :

1. 3D printed head.
2. 3D printed body.
3. 3D printed leg x2.
4. 3D printed feet.

III. Assemble guide, Software and App:
Otto++ can be programmed by Arduino and Scratch

1. Arduino lib: https://github.com/stembotvn/OttoDIY_Vbot/
2. mBlock Extension for Scratch coding: https://github.com/stembotvn/OttoDIY_mBlock_Extension
3. README.md tells you how to connect:
   • Servo Hip left to D2
   • Servo Foot Left to D4
   • Servo Hip right to D3
   • Servo Foot Right to D5
   • Buzzer to D13 (Active High)
   • HC06Rx to Arduino D7)
   • HC06Tx to Arduino D6
   • SRF04 Trigger to D8
   • SRF04 Echo to D9
   • Max7219 DATA (DIN) to D10
   • Max7219 CS to D11
   • Max7219 CLK to D12
   • Sound Sensor to analog A6,
   • Light sensor Left to analog A1
   • Light Sensor Right to analog A0
   • Battery: (-) -> GND; (+) -> switch -> Vin (NOT 5V)
4. Bluetooth control
   • App: android Zowi app (by bq) - https://play.google.com/store/apps/details?id=com.bq.zowi&hl=en
   • Config: github.com/stembotvn/OttoDIY_Vbot/tree/master/examples/HC06_BT_config
   • Firmware: github.com/stembotvn/OttoDIY_Vbot/tree/master/examples/Otto_BT_ZowiAPP