A knight to remember

So, there is a UK TV program that is set in a castle.
The company that supply the sets props and effects asked for me to animate one of the Knights.

Nothing too complicated for the first one, so it was decided on a simple turning head

First challenge is the detection system.  I decided early on that his eyes would be a pair of round Oled screens with real eyes displayed on them.

Either side of the screen I mounted some small, long range PIR sensors.  I covered half the sensor with a shield so that each sensor covered half of his field of view.

The helmet is pretty heavy, so it need a decent servo to turn it.  I found some with impressive weight abilities (although extremely expensive), but they did allow me to use direct drive.

An ESP32 runs the show.  Custom code produces a webpage for the Knight and this allows the user to configure all of the settings.
Attached to that is a pretty capable MP3 module and an amplifier. 

I added a whole pile of phrases to the sound system.  I ran them through my sound editing suite after converting the text to a male, English voice. 
I dropped the tone to make him sound a little bit more Knight like.

I added LEDs to the visor and the neck chainmail.    These we configurable from the webpage for colour, activation etc.

A single speaker mounted in his tummy provided more than enough volume.

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Inside his head

I drew out a head mechanism in CAD.
The main drive was the servo directly connected to the head.  This was all mounted on 100% infill printed PETG filament.

The eyes were mounted on a nice custom plinth, and space left for any electronics to go inside the head.
It was difficult to mount the helmet to the printed frame, as I did not want any visible fixings on the outside.

I made the frame expandable.  You could slide the frame out with slotted bolts to 'grip' the inside of the head.
I added industrial double sided tape to these mounts and they held very well.

The main support was the brass bolts for the original, raising mouth guard. I replaced these bolt and the were used as the main fixing solution.

A plinth was made with all the electronics on it.  This went inside the body.

A large 100mm bearing was used for the head rotation.  I did not want the servo taking all the load of the metal head.

The whole head assembly was made magnetic.  The Knight had a metal frame inside him, and there was a flat platform at the top.
A pair of large Neodymium magnets held his head on the frame well.

When you approached him, the appropriate PIR would detect you. This made his eyes turn in the direction of detection (or wake from sleep, depending on the webpage settings).
He then turns his head in the direction of detection and straightens his gaze.

After a user defined time delay, he would speak either a random or pre-set phrase.
After a delay, he return to looking directly ahead. 

You could set lots of actions or features on the webpage, which the EPS32 produced for local control.