DIY Minion Robot Made With Scrap and Arduino

Hello!

I guess you guys already know that I have a little baby. Even though he's small, he's already very watchful seeing the robots running around the house (we had much fun together with the mBot and his lights). So I made this buddy thinking it would be fun for him as well.

Currently I have not worked much with scraps, but I have a lot of them at my lab.

Long ago (I believe there are four years) keep this capsule (obtained from a Easter Kinder egg, which was used as the main body part of the robot) and recently remembered it and realized it would be ideal material to make a Minion.

So this week I decided to do something mostly with scraps.

After making some sketches and the templates, started the work, which took me only one afternoon to make the body and one more afternoon to the electronics.

List of materials and components:

• Kinder egg capsule;
• high impact polystyrene piece;
• a pair of wheels (obtained from Nutella pots);
• third wheel (obtained from an old cassete player system);
• a pair of micro DC geared motors with hubs and brackets;
• small ball bearing with flange;
• screws and nuts;
• Arduino UNO (note on the picture of the materials and components that an Arduino Nano is shown. It was my first option, but my Nano board have a mini USB connector and my mini USB cable is broken);
• L298N breakout board;
• HC-SR04 sensor;
• a pair of LiPo batteries;
• jumper wires;
• thin wires (for the hair).

Tools and others:

• hand drill;
• metal ruler;
• scissors;
• sandpaper;
• pliers;
• razor;
• screwdriver;
• permanent marker (black and blue);
• stick glue;
• instant adhesive (cyanoacrylate ester);
• masking tape;
• soldering iron;
• solder wire;
• heatshrink.

Step 1: Making the Body

The whole process of making the body is better shown on the "How to make a cool Minion robot?" video (above), but I'll describe here the process.

I put the "eyes" (HC-SR04 sensor) template into place, and marked the circles with permanent marker.

With razor cut the circles to fit the sensor.

With masking tape I set the "elastic" of the goggles, and painted it with black permanent marker. I also painted his mouth.

With blue permanent marker I painted his clothes.

With stick glue put the template for the "T" support of the base on a piece of polystyrene. With a 1mm drill I marked where will be some holes for screws and the small ball bearing later. With razor I cut the piece (with scissors on the rounded side), and with sandpaper I gave a better finish to the edges.

Joined the "T" support and the base of the capsule with instant adhesive (aligned the two parts with a screw in the middle of them, and removed it later - the screw). I sanded a bit before join the parts for better grip.

I put the hair (thin black wires) through a hole and glued it with instant adhesive.

With the templates of the wheels, made the holes.

Step 2: Electronics, Code and Additional Pictures

The electronics is quite simple, as follows:

HC-SR04 sensor

• VCC >> 5V
• Trig >> Arduino pin 10
• Echo >> Arduino pin 9
• GND >> GND

L298N

• ENA >> Arduino pin 3
• IN1 >> Arduino pin 4
• IN2 >> Arduino pin 5
• ENB >> Arduino pin 6
• IN3 >> Arduino pin 7
• IN4 >> Arduino pin 8

The LiPo batteries are connected in series (so 7.4V) and his positive passes through a switch and goes to the 12V connector of the L298N. The L298N have a 5V connector, which provides the power to the Arduino board (in the 5V pin). Arduino and L298N must have a common GND.

The only necessary soldering was to connect wires to the motors.

Arduino code

The code is very simple, only to avoid obstacles, and is available for download.