Creeper-BOT (Creeper Pet)

I always wanted to make a quadruped robot of my own and the Minecraft contest was a good excuse. Besides, I really wanted a Creeper 'pet'.

In this Instructable I'll share how I made it and give you a guide if you want to make your own.

I assume you have had some experience with electronics, but if you have any questions please feel free to ask on the comments and I'll do my best to answer them.

Credits:

Reading RC receiver with Arduino: https://ryanboland.com/blog/reading-rc-receiver-va...

PCA9685 Tutorial: http://www.naylampmechatronics.com/blog/41_Tutoria...

Step 1: Materials

9x MG90S servos

18x M2 nuts and bolts

8x M3 bolts

4x 45mm M3 standoffs

4x 25mm M3 standoffs

1x Arduino UNO

1x PCA9685 servo controller

1x Battery (I used a 2 cell 7.4V 1000mAh 20C LiPo)

Optional: A battery monitor to prevent over-discharge

1x Step-Down Regulator

Optional: A switch to disconnect the battery from the regulator

1x RC receiver and controller (I used a Eachine iA6 Rx and a Eachine i6 Tx)

Jumper cables (M-M, M-F)

Superglue to glue some of the 3D parts together

Velcro and anti-slip sticker. I used some I got from the supermarket from 3M brand.

You'll also need some Green filament to print the rest of the parts and a bit of black filament for the face.

Tools

You'll need a screwdriver for all your screws. A voltage meter to calibrate the regulator.

You'll also need a soldering iron and a bit of solder.

Step 2: Print the Parts

All of the parts were designed in Fusion 360.

You'll need to print the following in the specified quantities:

2x Foot A

2x Foot B

2x Leg bracket A

2x Leg bracket B

1x Base plate

1x Mid plate

1x Torso

1x Head bottom

2x Head sides

1x Head front

1x Head top

1x Head top cap

1x Head back

1x Head door

1x Face (in black color)

Step 3: Assemble the Legs

The easiest way to assemble the legs is by first screwing the servo arms into the feet and the leg brackets. Use the screws that came with the servo.

TIP. Taper the servo arms holes before attaching them to the 3D printed parts.

After you attach the servo arms, attach the foot servo to each of the leg brackets using the M2 screws and nuts.

Then attach the leg servos to the base plate, again with M2 screws and nuts.

Finally, attach the leg brackets to the leg servos in the base plate and then the feet to the feet servos.

Note: Route the leg servos' wires through the holes in the base plate.

Optional but recommended: Add anti-slip stickers to the bottom of the feet!

Step 4: Assembe the Torso

Attach the 4 25mm stand-offs to the base plate using 4 M3 screws.

Attach the 4 45mm stand-offs to the mid plate using 4 M3 screws.

Assemble mid plate on top base plate using 4 M3 screws and route servo wires through the holes.

Assemble the head servo to the torso.

Assemble torso on top of mid plate using 4 M3 screws and route servo wires through the holes.

Step 5: Assemble the Head

Using super-glue assemble the head pieces as shown in the picture and video.

After the head pieces are glued together, route the servo wires through the holes and screw the head to the head servo.

The "head top cap" and "head back door" prints close out the holes in the head. These two holes are meant for easy access to the electronics.

Step 6: Electrical Connections

Please follow the electrical connections as shown in the schematic.

You'll need to trim the step-down regulator to provide 5V (or the voltage your servos work with). Use a screwdriver and a voltage meter to do this.

You might need to splice some jumper cables together. Use solder and cover the splice with electrical tape or heatshrink.

I arranged the electrical boards inside the head as shown in the picture.

I used velcro tape to fix them to the head walls.

Step 7: Calibrate Servos

The creeper's movement only require two different positions for each servo. We'll calibrate those two positions now.

Upload the calibrate_creeper script (see attached) to the Arduino and open the Serial Monitor.

You'll manually position the robot as shown in each picture and take note of the servo values for each one.

To move a servo using the script, use keys Q/A, W/S, E/D.

To change which servo you're moving, use the Z/X keys.

To show the current servo values use any other letter, such as L.

Once you move the servos to the correct position, take note of the values and update the pos0 and pos1 arrays in the code.

After you update the arrays, you can re-upload the code to the board and use the 5-9 keys to preview the walking gaits.

Step 8: Play

Open the CREEPER_RC code and update the pos0 and pos1 array with the ones from the previous step.

Upload the code, turn on your RC transmitter and play!

Step 9: Future

In the future, I'd like to add more functions to the Creeper, such as:

Add a speaker to make sSsssSsssS and exploding sounds!

Add an RPi and a camera to get Creeper vision.

Please let me know if you have any cool ideas about future additions.

This is the end of this Instructable. Please let me know your comments and questions.

Thanks for reading.