K9 and meatballs

My wife saw a website that described how to take household items and embed them into models of other things.
An example of this is using split peas as rivets on the Dalek I made (Oh and that was her idea).

model k9
High tech steam punk style

One day a while ago after a spaghetti and meatballs meal. She held up the empty plastic bottle of spaghetti sauce and said I am going to make something from this.
After some thought she said Steampunk K9.
Out came the glue gun and a bunch of other things and here is the final creation.

Steam punk model
K9 steam punk style

Yes Master!

K-9, the robotic companion to the Fourth Doctor, was my first project and I learned a lot from making him. Since the BBC had long ago released plans for K-9, I thought that this would be an easy project to do. I was SO wrong. It was much harder to do than I imagined. I found the plans that the BBC released. Sadly several dimensions were missing.

finished K9
K9 front view

10 Things I would do differently next time

  1. Use a better amplifier.
  2. Add a method of sensing people to start interaction.
  3. Use servos to control the radar (ears), gun (nose) and wagging tail.
  4. Build the whole body from lighter materials.
  5. Change the head (in the plans issued by the BBC, the dimensions for the head are incorrect).
  6. Use an ISD2560 IC for the speech or similar IC.
  7. Remote control drive.
  8. Make the electronics accessible via a panel on the side of the body.
  9. Use PCBs instead of using stripboard for the electronic circuits.
  10. Make the electronics more modular.

I did not initially make a list of features that make it recognizable as a character. But if I had it would be like this.

  • Speech
  • Glowing eyes
  • Retractable sensor
  • Retractable gun in nose
  • Printed paper strip out of mouth
  • Oscillating dish ears
  • Tilting head
  • Television screen on side of dog
  • Wagging tail
  • Computer on back
  • Side panel removable
  • Remote control drive

Adding life

After playing around with some battery operated drill motors I felt that they were too long to fit inside K-9’s body side by side
I instead used 2 electric window up/down motors from a car.

The H-bridge worked fine however the weight of the body and the wheels being slightly misaligned made the wheels rub on the frame. When I powered it up the first 3 or 4 times K-9 shot across the floor proudly.

As they rubbed it got worse until the fuses started blowing. I gave up trying to fix this because it because I had made the motors very inaccessible. Lifting the body made its just too difficult to access the motors each time.

I did not really consider things being accessible

Flashing computer

For the ‘computer’ that sits on K-9’s back I purchased a large calculator that was the correct dimension and modified it to look somewhat authentic.

The lights that flash are LED’s controlled by a Pic16F84A programmed with JAL.

Basically it is the ‘Knight Rider style’ sample program that comes with JAL but with some slight modifications and some fancy wiring.

The head

The head was assembled last,
The TV K-9 has a gun that comes out just below his nose. I had the gun moving back and forth but no way to actually fit it in the head, plus the motor driver IC was getting hot, so I glued it in place and it is non movable.

Hardboard head
The real head painted with primer

K-9’s ears are two radar dishes that oscillate back and forth. I purchased some surplus stepper motors which would fit side by side inside the head. I then created a circuit to make them oscillate back and forth. Once powered up, the circuit worked marvellously, almost totally silent, and the ears rotated back and forth very smoothly. I noticed current consumption of the stepper motors was quite high.

Here are the ears moving


I had someone do the K-9 voice and modified the files with Audacity, which then I burned to a CD. I had a CD player that was controlled by a Pic16F84A IC for Play, Stop, FF, etc.
Here is where timing became an issue (and thus the down side of using this method).
As the CD does not provide feedback on what is happening, you cannot tell if it is playing or not or even which track is playing. I so everything had to restart from a reference point for each track, each track was exactly the same length and every thing was based on timing and then, when finished playing, back to that reference point.

Overall this is not the best way to control speech or music.


K-9 Body

The body and head were based on the plans that the BBC released.

A piece of plywood approx 29″ x 18″ is the base everything sits on.
Then I made a frame that was the size of the body and the skin sides were cut from hardboard and glued to the frame

Body made out of hardboard
Hardboard body


Building the body of the dog took a lot of sanding and filling.

The body was painted with car spray paint.
The neck piece was made from dryer hose painted black.
The eyes were red stained glass paint on some perspex.
Some tartan material folded and glued became the collar.
I had K-9 engraved on a dog tag.
Pipe insulation painted black made the edge stripping along the bottom.
Ears are pieces of screen door attached to thick gauge wire.
Stepper motors turn the ears from side to side.
For the tail of the dog a portable VHF radio antenna.
The bellows (tail) were molded using cardboard and air drying clay.

Side view K9
K9 you want to go outside?