Person Following Cart

Robots are getting more and more attention in many industries every day. As of today, robots are taking over most of the trivial jobs where once human attention was required.

Let's start up with some simple one - A bot that follows you as you go. There are many applications to this project for example like in Airports and Shopping complexes it can transfer goods for you as you walk freely.

In this Instructable we won't be building those industrial big machines but an Arduino based working model for the same cause.

Also, This instructable was made in collaboration with HATCHNHACK. Check out their amazing website for all your prototyping equipment, blogs, ideas, and much more.

Well, I am writing this as a general Instructable so I will try to get some alternatives if you can not find the parts that I am using. I will also add buy links so you can buy the items which you don't have in handy and so you can customize your bot with your creativity. For parts to make this project refer to hnhcart. They have good quality parts with an amazing price range.

• Microcontroller: well if you are a beginner try using an Arduino. Well, I am using Arduino Uno. Buy link for Arduino UNO

• Motors: any 12V motor will work. I am using 300 RPM generic 12 volts geared DC motors. You can also buy BO motors. Buy link for DC Geared boards | BO motors
• Motor driver: you will need a motor driver to run the motors as most microcontrollers cannot supply that much voltage. I am using an L298N which you can refer here to buy Motor driver.
• CHASSIS: For chassis, you have to buy a specific one for the motors you are using. For BO and DC greared motors you can refer this link
• Ultrasonic Sensor: I am using a generic ultrasonic sensor module HCRS04. buy link for the
• ultrasonic sensor.
• IR proximity sensor module: Any proximity sensor will work which can detect object detection for at least 20 cm.buy link for the sensor
• Jumper wires: we all need jumper wires to connect stuff. If you are a newbie you would need a bunch of these for different projects. you can buy some from here Male to male | Male to Female

• Battery: well I am using a 12v lipo battery for this project. if you don't have that you can always shift to generic 12v lithium-ion batteries. Or if you are using 9v BO motors you can even use a simple 9v battery. But be careful to check your motor specification before buying the battery as you can damage the motor if you supply higher voltage than the motor capacity. To buy 9v battery refer here.

• Breadboard/prototyping board: you will need something to connect all the wire. Here breadboard will come in handy. buy link for Breadboard | prototyping board

For this project, I am using 4 geared motor chassis which you can find easily. I am using 4 metal L shaped stands to mount my servo - head and a wooden box and as a carriage.

• To build up the chassis first mount the stands
• mount the motors and tires
• mount the servo
• leave the head and the box aside as you will need space to built up the rest of the bot. we will attach that at the end.

To supply sufficient juice to motors we need to set up the motor driver.

1. first, screw the +ve and -ve poles of the motor to the PTR connector of the motor driver.
2. then to power, the motor driver screws the +ve of the battery to 12v port and -ve to the GND port of the motor driver.
3. put the input pin of the motor driver to the PWM pin of Arduino as of your choice. REMEMBER to change to motor pins in you code accordingly.
4. add a switch between the +ve of the battery and the motor driver otherwise, you will have to keep disconnecting the battery when you are not using it. get 2 wires from the 5v and GND of the motor driver to the breadboard so you can power Arduino as well as other devices.

I glue gunned the sensors on a square metal plate as shown in the pic above

• attach all the 5v and GND to the 5v and GND of the breadboard to power the sensors and servo.
• attach the output pins of left and right IR sensors to the pin 12 and pin 13 of Arduino.
• attach the echo and trig pin of the ultrasonic sensor to pin 2 and pin 3 of Arduino.
• attach the input pin of servo to pin 5 of arduino.

I used double tape to fix Arduino and breadboard on the chassis as it also provides insulation on the back of Arduino.

power the Arduino by attaching the 5v and GND of the breadboard to the Vin and GND to the Arduino and you are good to go.

I am leaving a download link for the code whereas I will also explain the basic algorithm behind the code.

• at first, the bot will initiate a search function for the hand.
• as soon as an object is found, the bot will initiate the loop function
• in that, if the left IR sensor is triggered, the bot will turn right
• if the right IR sensor is triggered, the bot will turn left
• if object comes too close, the bot will go backward.
• if the object goes far away, the bot will go forward.

everything done, all is left for you to use your creativity to customize it and find your innovative use for the project.