DIY Human Shield: the Only Friend You Need

In our attempt to design and develop a useless machine, we decided to create a robot friend that becomes your one and only friend. The robot's job is to monitor you as you work or study by yourself. As soon as a friend or colleague approaches you to talk or hangout, the robot drives them away by yelling "leave me alone" and proceeding to chase them down until they are gone. That way, you are left alone peacefully with your work, more relaxed, and more productive. The DIY Human Shield is the only friend you'll need for success and prosperity! Your work (and loneliness) is his absolute top priority, and no one is getting in his way or yours.

Most of the required supplies will be available in a basic Arduino starter kit. We will need:

• Arduino Uno
• PIR (motion) Sensor
• Ultrasonic Sensor
• Speaker
• Breadboard
• DC 3-9V Motor (x4)
• Robot Wheels (x4)
• Jumper Wires
• 9V Battery
• Battery Clip
• Super Glue
• Cardboard
• Foam Board

Video Link: https://vimeo.com/686720347

Since we're using four DC motors to build this robot and allow it to move, we need to connect each motor to the Arduino board and the breadboard individually. Each motor has two sides from which we can connect it, a positive side and a negative side. The positive side of the motor is denoted by a red dot next to the connection point. In this step, we take the first motor and insert two jumper wires into it, one in each connection point/hole. The wire that is connected to the positive side will be attached to digital pin 4 on the Arduino. Since the negative side must be connected to the ground to draw power to the motor, and we have 4 motors to attach to the board, take a third jumper wire and connect one of the ground pins on the Arduino to a negative row on the breadboard. Once this is done, take the negative wire that we connected to the DC motor to the same row on the breadboard, the "ground" row. Glue the wires on the DC motor in place for additional security. Repeat these steps with the 3 other DC motors, only this time, the positive pins will connect to the digital pins 5, 3, and 2 on the Arduino, making sure to connect their negative sides to the ground row on the breadboard each time. Once the coding is completed, the motors should all spin in the same direction at the same speed.

Now that are motors are connected and working, we want to use our Arduino to create a link between an ultrasonic sensor and our motors. Essentially, the motors are what allow our robot wheels to rotate, hence making it move. The connection we will make here makes these motors reactive to our ultrasonic sensor. So, when the sensor detects a person or an object at a certain distance (specified in the code later on), this information is processed by the Arduino and used to make the robot wheels move. This is an essential step to make sure the robot is only moving conditionally, and not infinitely.

The ultrasonic sensor being used here has 4 different pins, the ground pin, VCC, Echo, and Trig. The ground pin is connected to our breadboard in the same way we connected our negative motor pins to our breadboard. The VCC pin is a power pin, thus, it must be connected to the 5V power pin. In the same way, we can create a connection between our 5V Arduino pin and the positive row on our breadboard using a jumper wire. Then we can connect our VCC pin from the ultrasonic sensor to the same row on the breadboard using a male to female jumper wire. Next, we will use the same type of jumper wire to connect our Echo pin to digital pin 10 on the Arduino, and likewise connect our Trig pin to digital pin 9 on the Arduino as well. Keeping these numbers in mind is important as we will reference them in our code later on.

The next step involves incorporating our PIR or motion sensor. The purpose of this sensor in the context of this project is to trigger the talking of the robot. The motion sensor has 3 pins, including a ground pin and a power pin. The middle remaining pin of the sensor will be connected to digital pin 7 on the Arduino board, as pertaining to the written code. The ground pin will be connected to the negative row on the breadboard, while the power pin will be connected to the positive row, as we've done in previous steps.

Once our PIR sensor is connected to the system, we need to connect it to the speaker to generate the robot's talking loop. Since the PIR sensor has one ground pin, and two other pins, we know we need to connect the two other pins to our speaker. The power pin is connected to the positive side of the speaker, while the remaining pin is attached to the negative side. Secure the wires with electrical tape or glue once they're in the correct place.

Once the circuit is complete, we will begin assembling the body of our robot, as this will house the circuit we just built in the previous steps. Cut out a rectangular piece of cardboard that is of a size large enough to hold up the circuit, with the breadboard being the largest element spatially. Once you have this piece, we can begin gluing our four DC motors to the bottom of it. Attach a robot wheel to each DC motor we have connected so that the robot is balanced on four wheels. Place the breadboard, the Arduino board, and most of the wiring on top of this base so we can construct a body around it. Secure them in place with a hot glue gun so that the wiring stays in place and doesn't move as the robot is moving.

Now that you have a base with wheels, you can begin adding individual pieces of cardboard around this base to construct a cube shape. Make sure a small window is cut through the top segment of the cube so that the wiring can be pulled up through the robot. Cut out a larger window in the back segment of the cube so that it makes the circuit and the wires easily accessible, in the case that any changes or fixes need to be made. This is convenient as you would not have to completely disassemble your robot!

For the robot head, push the ultrasonic sensor through a smaller cardboard rectangle. This will represent the eyes of the robot. Once this is cut through, we can assemble the remainder of the robot head, making sure to cut small slits in the cardboard in areas where wires need to pass through. At this point you can add color, paint, a costume, or facial features to give your robot its own personality! Since this robot is not very friendly, we added big angry eyebrows, and lips around the speaker to give the impression that our robot is yelling at you. Make sure everything is glued together, and the robot can move without any weight or balance issues. This is important because it needs to chase our enemies down, and it can't do that if its not fast and stable enough!!

The DIY Human Shield is the only thing that you can reliably say is completely useless at

making friends, because it does the exact opposite! Utilizing ultrasonic sensors and PIR motion

sensors, the Human Shield makes sure there isn’t any human being in your vicinity, all the while

shouting at anyone who comes near to leave you alone. The three watt speaker may be hard to

hear, but the ultrasonic sensor makes sure to follow whoever is in your personal space until they

run off, leaving you completely and utterly alone. Just the way you like it!