Cheesoid

"Why Cheesoid exist?"

Mitchell & Webb: Cheesoid

An unhappy robot designed to have a sense of smell but can only distinguish between its two operating modes: "CHEESE" and "PETROL".

Thoughts

Everybody loves robots: It's your plastic pal who's fun to have around! I'd like a robot too, and I'm going to build one goddamnit!!!

As with everything I want to build, it must be funny, and so Cheesoid is the ideal blueprint to follow.

It has (should have) speech limited to a number of pre-recorded phrases: -

• "Cheese"
• "Petril"
• "Help! Cannot see! Can only smell!"
• "Why Cheesoid exist?"
• etc.

Basic Construction

I have a cardboard cylinder (slightly smaller than the original) and a silver "nose hose". The nose hose will contain a bent rod that will be rotated by a servo or stepper motor. The robot can run on top of a R/C car to begin with. The donated R/C car at the space has no battery and I couldn't get the motor to run!

I plan to cover Cheesoid in silver-grey paper.

The nose hose needs to be mounted in a shallow box which in turn is fixed to the body.

The "CHEESE" or "PETROL" mode switch must be authentic!

Voice capability will just be some sort of recordable button box.

Object detector (that initiates the smelling process) would be awesome.

The ability to actually distinguish between the smell of cheese and petrol would be crazy-awesome!

Need: -

• R/C vehicle
• silver-grey paper or card
• nose rod and motor
• voice
• lamp eyes - one red, one green
• flashing LEDS
• automation!!!

Nose Stepper

• get to grips with random recovered stepper motors
  • This one is especially useful - taught me enough to proceed: http://www.stepperworld.com/Tutorials/pgUnipolarTutorial.htm
  • http://www.piclist.com/techref/io/stepper/..%5Csteppers.htm
  • http://www.instructables.com/id/Drive-a-Stepper-Motor-with-an-AVR-Microprocessor/
  • http://wwwhomes.doc.ic.ac.uk/~ih/doc/stepper/others/

A stepper motor will be used to drive the "nose". The curved nose hose is fixed to the body and doesn't rotate. Inside a rigid but bent rod will rotate, driven by the stepper. The stepper needs enough grunt! I have no idea how "grunt" is measured in ISO units - torque I guess. Speed and accuracy is not so important for this task but it is a learning experience.

So I chose a random biggish stepper motor (from the members' motor box)...

It has 6 wires that go to a 2x4 0.1" pitch connector. It says "MINEBEA" "TYPE 17PS-C035-03" -- hmmm...

• http://www.theprojectasylum.com/electronicsprojects/componentdata/minebeasteppedatacirca1999.html

1.7 inch, P = Precision, Hybrid, S = 3.6 Deg, C =2 & 4 Phase Hybrid, Motor Lengths = 0(?), Different Windings = 35, Version = 03.

OK, so the information on the side isn't much help in finding the voltage and current so using the magic knowledge on the pages listed above I gleaned some info using SCIENCE!!!!

The stepper turns out to be a Unipolar. It has 6 wires, 2 for the centre taps which should go to V+ and two each for the grounds of the half coils.

I identified the usage of the wires using my cheap multimeter and measured the half coil resistances: 36.9 ohms, 36.6 ohms, 36.7 ohms, 36.7 ohms.

Six wires

Brown	Black	Red
Green	Orange	White

Wire purpose

Coil B 1	Coil A Centre	Coil B 2
Coil A 1	Coil B Centre	Coil A 2

To be continued!!!

Display and Indicators

The eyes on the "real" Cheesoid just flash left-right, left-right with one eye being red and the other green. I'll stick with this for now as it's simple but I'm not sure I want to use two pins on my Xino. I'll look into that when I have the basics in place.

I have added an LCD display...

Why Cheesoid Exist?

This is a Seiko L2012 LCD module which can be driven straight from the Arduino example library. I modified a Xino to directly drive one with a 14-pin header soldered to the prototype area of the board. This module I rescued from the skip at work and it has some damage to the LCD but it is entirely usable.

Voice

• make cheesoid voice recordings
  • download FLV of youtube video and extract audio - DONE
  • slice and dice with audacity - DONE
  • investigate robot voice changers and try to get the Robert Webb voice perfect
    • http://en.wikipedia.org/wiki/Festival_Speech_Synthesis_System

Movement and Power

Although I eventually want the robot to be pretty autonomous, initially I guess any kind of movement will be good. I imagine simply mounting the body on a reasonably powerful R/C car or tank. I'm going to have to get to grips with servos and R/C in general. I'll be looking out for tank track parts (e.g. bike chain tracks) in the meantime for a more serious robot movement base.

• http://www.societyofrobots.com/

For power I want to try out using some of the 12v and 6v lead acid batteries from the Emergency Roadside Telephone. I have recharged a 12v one and it seems quite happy after being sat on a shelf for many years! I also have my solar panel and I'd like to make use of it for recharging.

--Michael Erskine 16:38, 3 May 2011 (BST)