# <img src="./imgs/hexapod-logo.svg" alt="logo" width="64"/> Hexapod
A Hexapod Robot using Raspberry Pi Zero W
## Introduction
This is a hexapod robot based on [Smallp Tsai ](https://github.com/SmallpTsai )'s [hexapod-v2-7697 ](https://github.com/SmallpTsai/hexapod-v2-7697 ) project.
This project reused most of the mechanical design in the original project, but with a full redesign of the circuits and software.
The table below shows the difference between this project and the original one.
| | Original hexapod-v2-7697 | This project |
| --------------- | ------------------------ | ----------------------------------------------- |
| Controller | Linkit 7697 | Raspberry Pi Zero W or Raspberry Pi Zero W 2 |
| PWM control | Custom circuit board | 2 x PCA9685 motor driver boards |
| DC-DC | 7 x mini360 modules | 2 x XL4005 5A Max DC-DC modules and 1 x mini360 |
| Power | 2S Lipo battery | 2 x 18650 batteries |
| Remote | BLE | WiFi |
| Remote software | Android and iOS | PC, Android (WIP) |
https://user-images.githubusercontent.com/471808/148647807-02e3e901-6181-4473-8ac4-3b5998fa8d17.mp4
## Mechanism
### Bill of Materials (BOM)
#### Servos
18 TowerPro [MG92B ](http://www.towerpro.com.tw/product/mg92b/ ) are required.
> The dimension of 3d printed part is highly dependent on the servo's size. Modification is required if you want to use alternative servos.
#### 3D-Printed Parts
##### Body x 1
| Filename | Thumbnail | Required |
| -------------- | ----------------------------------------------------------------------- | -------- |
| body_top | < img src = "./imgs/body_top.jpg" alt = "body_top" width = "300" / > | 1 |
| body_bottom | < img src = "./imgs/body_bottom.jpg" alt = "body_bottom" width = "300" / > | 1 |
| body_side_wall | < img src = "./imgs/body_side_wall.jpg" alt = "body_side_wall" width = "300" / > | 2 |
| body_back_wall | < img src = "./imgs/body_back_wall.jpg" alt = "body_back_wall" width = "300" / > | 1 |
| battery_box | < img src = "./imgs/battery_box.jpg" alt = "battery_box" width = "300" / > | 1 |
| battery_holder | < img src = "./imgs/battery_holder.jpg" alt = "battery_holder" width = "300" / > | 2 |
##### Leg x 6
| Filename | Thumbnail | Required |
| --------------- | ------------------------------------------------------------------------- | -------- |
| thigh_top | < img src = "./imgs/thigh_top.jpg" alt = "thigh_top" width = "300" / > | 1 (x6) |
| thigh_bottom | < img src = "./imgs/thigh_bottom.jpg" alt = "thigh_bottom" width = "300" / > | 1 (x6) |
| joint_cross | < img src = "./imgs/joint_cross.jpg" alt = "joint_cross" width = "300" / > | 1 (x6) |
| joint_top | < img src = "./imgs/joint_top.jpg" alt = "joint_top" width = "300" / > | 2 (x6) |
| joint_bottom | < img src = "./imgs/joint_bottom.jpg" alt = "joint_bottom" width = "300" / > | 2 (x6) |
| leg_top | < img src = "./imgs/leg_top.jpg" alt = "leg_top" width = "300" / > | 1 (x6) |
| let_bottom | < img src = "./imgs/leg_bottom.jpg" alt = "leg_bottom" width = "300" / > | 1 (x6) |
| foot_top | < img src = "./imgs/foot_top.jpg" alt = "foot_top" width = "300" / > | 1 (x6) |
| foot_bottom | < img src = "./imgs/foot_bottom.jpg" alt = "foot_bottom" width = "300" / > | 1 (x6) |
| foot_ground | < img src = "./imgs/foot_ground.jpg" alt = "foot_ground" width = "300" / > | 1 (x6) |
| foot_tip | < img src = "./imgs/foot_tip.jpg" alt = "foot_tip" width = "300" / > | 1 (x6) |
| servo_horn_j1j2 | < img src = "./imgs/servo_horn_j1j2.jpg" alt = "servo_horn_j1j2" width = "300" / > | 2 (x6) |
| servo_horn_j3 | < img src = "./imgs/servo_horn_j3.jpg" alt = "servo_horn_j3" width = "300" / > | 1 (x6) |
#### Others
| Name | Spec | Thumbnail | Required | Note |
| --------- | ------- | ---------------------------- | -------- | ------------------------------------------------- |
| Screw | M2 6mm |  | 54 | Servo Arm: 1 x 18< br > Joint: 4 x 6< br > Thigh: 2 x 6 |
| Screw | M2 10mm |  | 24 | Thigh: 1 x 6< br > Pin lock: 1 x 18 |
| Screw | M2 30mm |  | 36 | Servo: 2 x 18 |
| Nuts | M2 |  | 36 | Servo: 2 x 18 |
| Pin (304) | M4 6mm |  | 18 | Servo: 1 x 18 |
### Leg Assemble
#### Assembly video
< a href = 'https://youtu.be/oaAE5fC09KQ' > < img src = 'http://img.youtube.com/vi/oaAE5fC09KQ/mqdefault.jpg' / > < / a >
#### Exploded view
< img src = "./imgs/mech_leg_exploded.jpg" alt = "LegAssemble" width = "500" / >
#### Detailed steps
- **Step 1** - Combine `thigh_top` , `MG92B` and `thigh_bottom` , use M2x30mm screw and nut to secure them together.
< img src = "./imgs/mech_leg_1.jpg" alt = "LegAssemble1" width = "500" / >
- **Step 2** - Grab one `joint_cross` , `joint_top` and `joint_bottom` and combine them
< img src = "./imgs/mech_leg_2.jpg" alt = "LegAssemble2" width = "500" / >
- **Step 3** - First put 2 x `MG92B` , `leg_top` and `leg_bottom` together with M2x30mm screw and nut. Then attach `joint_top` and `joint_bottom` altogether
< img src = "./imgs/mech_leg_3.jpg" alt = "LegAssemble3" width = "500" / >
- **Step 4** - Grab `foot_top` , `foot_bottom` and `foot_ground` (and `foot_top` ) and assemble them.
< img src = "./imgs/mech_leg_4.jpg" alt = "LegAssemble4" width = "500" / >
- **Finish** - Great, you got 1 leg done, 5 more to go :)
< img src = "./imgs/mech_leg_5.jpg" alt = "LegAssemble5" width = "500" / >
## Electronics
### Bill of Materials (BOM)
| Name | Thumbnail | Required |
| -------------------------- | ---------------------------------------------------------------------- | -------- |
| Raspberry Pi Zero W or W 2 | < img src = "./imgs/zero2-close-up.webp" alt = "raspberry pi" width = "300" / > | 1 |
| PCA9685 motor driver | < img src = "./imgs/PCA9685.jpg" alt = "PCA9685" width = "300" / > | 2 |
| XL4005 DC-DC step down | < img src = "./imgs/XL4005.jpg" alt = "XL4005" width = "300" / > | 2 |
| Mini 360 DC-DC step down | < img src = "./imgs/mini360.jpg" alt = "mini360" width = "300" / > | 1 |
| Toggle switch | < img src = "./imgs/toggle_switch.jpg" alt = "toggle_switch" width = "300" / > | 1 |
### Connection Diagram
< img src = "./imgs/diagram.svg" alt = "diagram" width = "800" / >
## Software
### Raspberry Pi
#### Requirements
Raspberry Pi is running [`Raspberry Pi OS` ](https://www.raspberrypi.com/software/ ).
- Enable `I2C` through `raspi-config`
``` bash
sudo raspi-config
```
- Install required packages
``` bash
sudo apt-get install python3-numpy python3-pip
```
- Install required Python modules
``` bash
pip3 install adafruit-circuitpython-servokit
```
> Tips: It is convenient to debug code on Raspberry Pi through VSCode's remote feature.
#### Running
The hexapod program, located under `./software/raspberry pi/` , is written in Python. Use the following command to start it manually.
``` bash
python3 hexapod.py
```
### PC
PC program source files are located under `./software/pc/` . The compiled program can be downloaded under the [release ](https://github.com/rookiepeng/hexapod/releases ) page.
< img src = "./imgs/pc_interface.jpg" alt = "pc_interface" width = "400" / >
- Find the correct IP address of the Raspberry Pi on the hexapod
- Connect to the hexapod using the IP address
- Use the buttons on the panel to control the hexapod
### Android
< img src = "./imgs/screenshot_connect.png" alt = "screenshot_connect" width = "400" / >
< img src = "./imgs/screenshot_control.png" alt = "screenshot_control" width = "750" / >
