In this lesson, we will show you how to connect 4 DOF robot arm to Raspberry Pi  and Use web browser to control the 4 servo joint of the arm.

No. Picture Device Qty. Accessories Link
1 Raspberry Pi board 1
2 MG995 or SG90 Servo Motor 4 M2.2*8 Self Tapping Screw x 2
M2*4 Self Tapping Screw x 1
Click here to buy
3 PCA9685 1

PCA9685 Raspberry Pi Physical Pin#
V+ Vin

PCA9685 Servo
PWM 15 Finger servo
PWM 14 Wrist servo
PWM 11 Arm servo
PWM 10 Base servo

Step 1: Please run following command to download  Linux script file:


then type the following command to install python program:


Step 2: type following command to enter the folder osoyooarm

cd osoyooarm

Step 3:  Find your Raspberry Pi IP address by typing following command:

hostname -I

You will see the IP board IP address like this: fd00:bc4d:fba4:fea2:8bea:ed3f:cfbd:ba1e

In above example, is the IP address of our Pi. You need to use this IP address to update the python code in Step 4.

Step 4:  Type the following command to edit the file


Change the default ip address in line 15 to the raspberry pi IP address from Step 3, and cick “Ctrl”+”X” then “Y” to save the file and then click “enter” to exit

Step 5: Run the code by typing command

sudo python3 ~/osoyooarm/

Step 6: In your PC or cell phone which is the same wifi network of your Raspberry Pi, open the browser and visit http://your_RaspberryPi_ip_address, you will see following UI

In the page, there are 4 Sliders which can control for servo joint, you can move the slider in order to rotate the servo and change arm and finger positions.

Marcelo Rovai : Python WebServer With Flask and Raspberry Pi