Monster Chan - The credit card walking robot

Let's Make Robots Robots
1

The parts list

  1. Some tie-wraps (for the cabling)
  2. Foam tape
  3. An Arduino - I used a VISduino
  4. An Arduino sensor shield
  5. Battery box + batteries - I used 4xAAA in the final design
  6. An IR remote control + the received board - I used the Keyes one
  7. 2 credit card sized pieces of plastic
  8. 7x micro servos - I used the SG-90 ones, but have use MG-90S in similar designs
  9. An ultra sonic module + cable - I used HC-SR04
  10. Some large paper clips (for legs).

Reset the servos

  1. download the sketch (from robot-v6.zip)
  2. Install the Servo, IRremote, and NewPing libraries.
  3. Get it to compile - See the comments in the code, you'll need to edit the library code to get them to compile together
  4. Download it/Run it
  5. One at a time, go through all the servos, and plug them onto output 2, this will reset the servo to it's mid-point.

Building the robot

  1. Make the legs, straighten a large paperclip, then feed it through the servo horn. You might need to use a small drill to enlarge the holes.
  2. Add foam tape to the base card
  3. Stick the servos down one side of the base card (output shafts towards the back edge)
  4. Add the ultrasonic movement servo
  5. Stick the servos down the other side of the base card (output shafts towards the back edge)
  6. Cut a slot in the top card, and use more foam tape to stick in on top
  7. Add the arduino and the battery box
  8. Add the ultra sonic sensor, and the IR receiver

Connections

  • Out 2 = right rear
  • Out 3 = right lift
  • Out 4 = right front
  • Out 5 = left rear
  • Out 6 = left lift
  • Out 7 = left front
  • Out 8 = ultrasonic movement servo
  • In 11 = IR receiver
  • Out 12 = Ultrasonic trigger
  • In 13 = Ultrasonic receive

Notes:

  • The servos can draw a lot of current, and this can reset the Arduino. To prevent this I put a big capacitor across the battery input (I have a 4700uF/16V in my box, that I used).
  • There are several different sets of IR remote control codes, the code handles two of them, you can add more to the case statements.
  • You can fine tune the leg positions by changing the code.

Remote comands

  • up = go forward
  • down = go backwards
  • left = turn left
  • right = turn right
  • OK = Stop / sit
  • * = Auto (use ultrasonics to avoid obstacles)
  • # = test, output the current ultrasonic range to the RS232 port, and move each of the legs (right rear, right mid, right front, left rear, left mid, left front).
  • 1-9 = set this number of steps
  • 0 = keep going until stopped

An easy to build, Arduino powered, walking robot, with manual IR remote control, with automatic mode that uses ultrasound to avoid obsticles

This is a companion discussion topic for the original entry at https://community.robotshop.com/robots/show/monster-chan-the-credit-card-walking-robot
2

Neat!
Really cool bot, Roger.

Just make sure it doesn’t start ordering upgrades for itself. :slight_smile:

3

No credit cards were harmed in the making of this robot.

The original version used a couple of expired credit cards. This version used a store points card, and a hotel door card.  So I think I’m safe.

4

Very nice!

That whets my appetite for hexapods. I also like the detailed write-up, thanks!

5

My first Arduino project

Thanks…

I only have access to a limited number of tools, so worked out something that would be simple to construct.
When I laid out the servos, I realised that it could be pretty small, and found that an expired credit card was about the right size.
So the original had the servos sandwiched between two expired cards. It was controlled by a PIC (actually a PIC16F676). The original code just took Servo movement commands from the PC via RS232. Later I added an IR remote control, so it became autonomous.Then it gained an echo sensor, then finally a servo to move the echo sensor.
This was all done in PIC assembler code, and debugging was difficult. Also the PIC I was using was running out of RAM (only 56 bytes) and codespace (only 1K instructions).

So on International Arduino Day, at the Taipei hackerspace, I converted it to use Arduino.
Quite a few people were interested in building one, so figured I ought to document it somewhere. A while back I’d found letsmakerobots.com, so over the weekend, when I finally got a day to build another one, I documented the steps as I went!