Cheap and Opensource Robot Dog (CORD)

CORD is an open-source project that offers a starting point for those new to legged robotics or anyone seeking to build a dog robot, develop gait algorithms or contribute to a quadruped robot project. The robot's design and structure prioritize simplicity and cost-efficiency.

CORD v1.0 :

1. Goal

Build a robot dog using only sg90 servos and an Arduino.

2. Recipe

1. 8x SG90 servos (18.99$)
2. Arduino (Uno or Nano) (27.60$)
3. 3D printed parts (150 x 150 x 150 printer printable)
4. 2x 18650 Lipo (3.7V, 3500mAh)
   1. Power souce to connect to V_in and Gnd of Arduino (7.89$)
5. Breadboard power rail (2.99$)
6. Jumper Wires (6.98$)

Total of 64.45$ (if all components need to be purchased).

3. Render

Designed with Fusion 360

4. Structure

leg 5         leg 6
|                |
|                |
|-| leg 1      |-| leg 2
  |            |
  |____________|
  |            |
  |    BODY    |
  |____________|
  | leg 3      | leg 4
  |            |
|-|            |-| 
|                |
|                |
leg 7      leg 8

5. Instructions

1. Acquire required components
2. Print, put together 3D print parts
3. Calibrate legs
   1. Configure resting servo angles
   2. Cord_initialize.ino
   3. Cord_stand.ino
   4. Cord_crawlGait.ino
4. Develop new gait algorithms & functions!

6. CORD v1.0

7. Moving Forward:

1. MG90s: Higher torque servos (13.6g;2.2kg/cm;10/27.59$)
   1. SG90 (9g;1.6kg/cm;10/18.99$)
2. PCA9685: Servo Driver (scalable and organized servo control)
3. LM2596: Step Down Converter
   1. Limitation: Output current limited to 2000mAh
4. Arduino Nano: Reduce size
5. Arduino Ultrasonic Sensor: Obstacle avoidance
6. Trot gait, creep gait