Introduction: Bluetooth Robot Arm Using Single Motor Driver

About: I'm a experienced software engineer loved to electronics and robotics.

Welcome to my Instructable.

In this instructable I'm going to show you how to convert Wired control robot arm to Bluetooth robot arm using single motor driver. This is a work from home project done under curfew state. So this time I have only one L298N motor driver. If you check wired control robot arm its contains with 5 motors. So if we have 3 L298N motor drivers we can control 6 motors (L298N driver can control 2 motors bi-direction) and easily we can convert it to Bluetooth robot arm using arduino and L298N 3 drivers. But as of current situation I have only one L298N motor and several servo motors. Let see how to do this task.

You will need following items to do this.


  • Finalized wired control robot arm
  • Arduino board (I'm using Arduino Nano)
  • Bluetooth module (H06)
  • L298N motor driver
  • Bread board
  • Jumper wires
  • Servo motor
  • Mini bolts and nuts

Step 1: Finalize Wired Control Robot Arm

To do this project you will need Wired control robot arm. This can be buy in eBay or Amazon. if you don't have wired control robot arm you can make that using gear motor also connecting few plastic arm parts. I'm not going to describe how to assemble this wired control robot arm you bough. Its show in this video how to assemble it.

Step 2: Prepare Multiple Motor Control Unit

This is the main concept I'm going to use in this project. Now when you check Arduino Motor driver working structure its as below.

  1. Connect E1, E2 in Motor driver to Arduino board Pin 9, 11
  2. Connect motor wires to Motor driver Output 1, 2 connectors
  3. Now whats happens is when you give E1 HIGH, E2 LOW motor running to a direction (say clockwise)
  4. If you change those E1 LOW, E2 HIGH then motor running to other direction (say anti clockwise)
  5. Now whats happen if you connect 5 motors to this Motor driver Output 1,2 connectors
  6. Then all the motors going to work same way but speed may be low due to power, you can connect external power to motor driver +12v connector
  7. So if we can connect one by one motor wires to motor driver output 1 or 2 connectors the particular connected motor only working.
  8. That is the concept I'm going to use to control robot arm.
  9. To do that I can use Servo motor. With different degree angle I'm going to short circuit the Output pin 1 or 2 wire with different motor wire.
  10. Check the above pictures for more understand.
  11. Also we need to get correct degree to connect pins. For that you can use a Potentiometer with attached Arduino code and when check serial monitor you can find the degree.
  12. You can use this concept to short circuit also for other purposes.

Step 3: Code for Bluetooth Connection and Finalize the Project

Now connect the wired control robot arm wires to above created Servo motor related short circuit pins. And add Bluetooth module. You have to connect Bluetooth module TX to Arduino RX and Bluetooth module RX to Arduino TX pins and connect power wires also. Servo motor also need to connect Arduino board and with Bluetooth connection input character we are going to write servo motor degree.

You can download any Bluetooth related app to phone and according to app configurations and out put characters you can change the Arduino code. I have used Arduino Bluetooth Controller app to do this.

When you try to run this with Computer usb power some time motors not working due to power not enough for Servo motor and motor drivers. You can connect external power to motor driver if happens.

This is a model implementation and did with limited resources. If you have 3 L298N motor drivers this can be done easily.

Also above step 2 mentioned short circuit method can be used to other need also.

Thank you for watching.

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Arduino Contest 2020