Ryan Chan
Published © GPL3+

Recordable Cardboard Robot Arm

A robotic arm made from easily available materials that can record and replay positions.

BeginnerFull instructions provided1.5 hours8,218

Things used in this project

Hardware components

Arduino UNO
Arduino UNO
×1
Normal Sized Servo
×3
SG90 Micro-servo motor
SG90 Micro-servo motor
×1
Breadboard (generic)
Breadboard (generic)
×1
5V Power Supply
×1

Software apps and online services

Arduino IDE
Arduino IDE
Python

Hand tools and fabrication machines

Hot glue gun (generic)
Hot glue gun (generic)

Story

Read more

Custom parts and enclosures

Cardboard Cutout Template

Schematics

Wiring Schematics

Code

Python User Interface

Python
from tkinter import *
from tkinter import filedialog
import serial
import time

port_opened=False

def set_port():
    global port_opened,arduino
    com_port= port_input.get()
    arduino=serial.Serial(com_port,9600)
    port_opened=True
    print ("COM port set to: "+com_port)

def send_positions(position):
    message = "{0:0=3d}".format(position[0])+"{0:0=3d}".format(position[1])+"{0:0=3d}".format(position[2])+"{0:0=3d}".format(position[3])+"{0:0=3d}".format(position[4])+"\n"
    arduino.write(str.encode(message))
    print(message, end='')
    time.sleep(0.2)

saved_positions = []

def save_positions():
    saved_positions.append([servo1_slider.get(), servo2_slider.get(), servo3_slider.get(), servo4_slider.get(), servo5_slider.get()]);
    print("saved positions: "+str(saved_positions))

def play_positions():
    for position in saved_positions:
        print("playing: "+str(position))
        send_positions(position);
        time.sleep(1)

def clear_all_positions():
    global saved_positions
    saved_positions = []
    print("cleared all positions")

def clear_last_positions():
    global saved_positions
    removed = saved_positions.pop()
    print("removed: "+str(removed))
    print("saved positions: "+str(saved_positions))

def open_file():
    global saved_positions
    filename = filedialog.askopenfilename(initialdir = "/", title = "Select a File", filetypes = (("Text files","*.txt*"),("all files","*.*")))
    file = open(filename, "r")
    data=file.read()
    saved_positions=eval(data)
    file.close()
    print("opened: "+filename)

def save_file():
    save_file = filedialog.asksaveasfile(mode='w', defaultextension=".txt")
    save_file.write(str(saved_positions))
    save_file.close()
    print("saved file")

def instructions():
    print("1.) Set the Arduino's COM port and click Enter. This can be found in Device Manager in Windows")
    print("2.) Move the arm's servos using the sliders")
    print("3.) To record a position, click on Record Position")
    print("4.) To replay the recorded positions, click on Replay Positions")
    print("\nTo save what you've recorded, got to File > Save File.")
    print("To open a previously saved file, got to File > Open File.")

window = Tk()
window.title("Robot Arm Controller 2")
window.minsize(355,300)

port_label=Label(window,text="Set Port:");
port_label.place(x=10,y=10);
port_input=Entry(window)
port_input.place(x=10,y=35)
port_button=Button(window, text="Enter", command=set_port)
port_button.place(x=135,y=32)

servo1_slider = Scale(window, from_=180, to=0)
servo1_slider.place(x=0, y=100)
servo1_label=Label(window,text="Servo 1")
servo1_label.place(x=10, y=80)

servo2_slider = Scale(window, from_=180, to=0)
servo2_slider.place(x=70, y=100)
servo2_label=Label(window,text="Servo 2")
servo2_label.place(x=80, y=80)

servo3_slider = Scale(window, from_=180, to=0)
servo3_slider.place(x=140, y=100)
servo3_label=Label(window,text="Servo 3")
servo3_label.place(x=150, y=80)

servo4_slider = Scale(window, from_=180, to=0)
servo4_slider.place(x=210, y=100)
servo4_label=Label(window,text="Servo 4")
servo4_label.place(x=220, y=80)

servo5_slider = Scale(window, from_=180, to=0)
servo5_slider.place(x=280, y=100)
servo5_label=Label(window,text="Servo 5")
servo5_label.place(x=290, y=80)

save_button=Button(window, text="Record Position", command=save_positions)
save_button.place(x=10,y=220)

clear_button=Button(window, text="Clear Last Position", command=clear_last_positions)
clear_button.place(x=120,y=220)

clear_button=Button(window, text="Clear All Positions", command=clear_all_positions)
clear_button.place(x=120,y=255)

play_button=Button(window, text="Replay Positions", command=play_positions, height=3)
play_button.place(x=250,y=220)

menubar = Menu(window)
filemenu = Menu(menubar, tearoff=0)
filemenu.add_command(label="Open File", command=open_file)
filemenu.add_command(label="Save File", command=save_file)
menubar.add_cascade(label="File", menu=filemenu)

editmenu = Menu(menubar, tearoff=0)
editmenu.add_command(label="Clear last position", command=clear_last_positions)
editmenu.add_command(label="Clear all positions", command=clear_all_positions)
menubar.add_cascade(label="Edit", menu=editmenu)

helpmenu = Menu(menubar, tearoff=0)
helpmenu.add_command(label="How to use (printed in console)", command=instructions)
menubar.add_cascade(label="Help", menu=helpmenu)

window.config(menu=menubar)

while True:
    window.update()
    if(port_opened):
        send_positions([servo1_slider.get(), servo2_slider.get(), servo3_slider.get(), servo4_slider.get(), servo5_slider.get()])

Robot Arm Arduino Code

Arduino
#include <Servo.h>

Servo servo1;
Servo servo2;
Servo servo3;
Servo servo4;
Servo servo5;

int servoPositions[5];

void setup() {
  Serial.begin(9600);
  servo1.attach(3);
  servo2.attach(5);
  servo3.attach(6);
  servo4.attach(9);
  servo5.attach(10);
}

void loop() {
  while(Serial.available()){
    String input = Serial.readStringUntil('\n');
    servoPositions[0] = input.substring(0,3).toInt();
    servoPositions[1] = input.substring(3,6).toInt();
    servoPositions[2] = input.substring(6,9).toInt();
    servoPositions[3] = input.substring(9,12).toInt();
    servoPositions[4] = input.substring(12,15).toInt();
  }

  servo1.write(servoPositions[0]);
  servo2.write(servoPositions[1]);
  servo3.write(servoPositions[2]);
  servo4.write(servoPositions[3]);
  servo5.write(servoPositions[4]);
  
  delay(500);
}

Credits

Ryan Chan

Ryan Chan

8 projects • 140 followers
I like turtles. I also like robots.

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