Single Degree - Freedom Robotic Arm

Robotic Sensors & Signal Processing

This repo is for testing servo with raspberry pi 3b+ and uses python code for controlling the servo.

Things to do in this project are:

• Calibration Servo using Limit Switch
• Rotating 90° after Homing.
• Controlling the servo using potentiometer.
• Detecting objects using a Ultrasonic sensor.
• If the object is too close (Less than 15 cm) LED, should turn ON.
• If the object is too close, (Less than 15 cm) servo should be disabled while operating the potentiometer.
• When the potentiometer is "0" the servo should move to 0° and also should activate the LED indicating the servo reached 0°.
• When the potentiometer is "1023" the servo should move to 90° and also should activate LED indicating the servo reached 90°.

To keep things neat. I made a case to place my components.

Check out this like to print for case for yourself

This is the case 3D-model & design revisions "DFMA"

Wiring Diagram

Flow Chart

Pin Configuration

In this project, I have used the Raspberry Pi 3b+ model.

Note : In Raspberry pi, you cannot drive 5V OUTPUT/INPUT sensor (or) actuator.

Hardware :

• Raspberry Pi 3b+
• MCP3008 - ADC (Analog to Digital Convertor)
• Limit Switch
• Servo - SG90
• 10k Potentiometer
• Ultrasonic Sensor (HC-SR04)
• Red LED
• Green LED
• Some Resistors (220E , 1K , 470E, 750E)

Raspberry Pi 3b+ Pinouts - Pin Configuration

                         3.3V - |1      2| - 5V
                                |3      4| - 5v
                                |5      6| - GND
                                |7      8| - Limit Switch (INPUT)
                                |9     10| - LED (Human Detection - OUTPUT)
                                |11    12| - Servo (PWM - OUTPUT)
                                |13    14|
                                |15    16|
                                |17    18|
                  MOSI (SPI0) - |19    20|
                  MISO (SPI0) - |21    22|
            Serial CLK (SPI0) - |23    24| - CS (Chip Select - SPI0)
                                |25    26|
                                |27    28|
                                |29    30|
                                |31    32|
                                |33    34|
                                |35    36| - LED ( 0° Position - OUTPUT) 
    Echo (Ultrasonic Sensor) -  |37    38| - LED ( 90° Position - OUTPUT)
                                |39    40| - Trig (Ultrasonic Sensor)

These are the BMC pins of raspberry p, which means physical pins.

MCP3008 Pinouts - Pin Configuration

    (Potentiometer) Channel 0 - |1      2| - 3.3V
                    Channel 1 - |3      4| - 3.3v
                    Channel 2 - |5      6| - GND
                    Channel 3 - |7      8| - Serial CLK 
                    Channel 4 - |9     10| - MISO 
                    Channel 5 - |11    12| - MOSI
                    Channel 6 - |13    14| - CS (Chip Select)
                    Channel 7 - |15    16| - GND

Software Installation Video

Here the step by step video for installing and setting RPi.

Working Video

Here is the video performing the requirements.