3D-Printing – Busy Ducks

Upgrading Robie The Robot.

duckman — Tue, 21 Apr 2020 02:27:55 +0000

A Rare Find

I was in an vintage collectables store and saw a beaten up old ‘Robie the Robot’ forgotten at the back of a shelf. It’s dome was cracked and it’s remote missing. Robot collectors are quite voracious in Canberra with most robots snapped up within days. However, it seems nobody relished this rough robotic remnant, so I got it cheap.

This robot was also known as: Tandy Robie, Radio Shack Robie, Robie the Robot, Talking Robie, RS 4061, Robocom 1000, Robie Parlant, Robocom Robot (Super). There is a good write up about the robot on theoldrobots.

Robie The Robot, as purchased.

Tear Down

Disassembling Robie I discovered a typical 80’s remote control toy. RC circuitry oozing with leaking capacitor electrolyte and decayed protective lacquer. Apparently the built in speaker could talk, but looking at the circuitry, my guess is it functioned as a wally talky, playing a voice signal from the remote. I didn’t have the remote so I can’t confirm.

The motors were the “old style”; power hungry and weak. The Achilles heel that made all 80’s moving toys kinda nerfed.

The front screen was fake, the heads and arms were not designed to move. I will need to fix all this.

A New Brain.

Decided to throw a pi in there, with a monitor that fits the front screen and a camera because that would be cool.

For the display, a generic five dollar 2.2″ SPI TFT LCD that sells for arduino projects works well (fits just behind the front monitor panel). The stock plastic used for Robies display is way to dark for the screen to be visible, so I used a Fresnel lens instead (you can get them from the two dollar shop, sold a book magnifiers).

A front assembly was 3d printed to hold the pi, monitor and camera (such that everything lined up, and the camera could see out of the hole previously used for the frontal on/off switch.

Design in Fusion 360, screen is mounted on the green sled.
Rear
Front
Empty shell, wit Fresnel lens.
Mount pi.

Motorising the Head

A turntable system was created in OpenSCAD, using the awesome parametric gear library by Dr Jörg Janssen. I didn’t have a 3d printer, so I printed via the ANU Makerspace.

The turntable is driven by a 28byj-48 stepper motor, with a ULN2003 Darlington transistor array driver.

I discovered the original broken dome was most likely not a custom mould, but a security camera dome. I had some difficulty justifying a proper replacement as Australian retailers wanted over $50 for a replacement security camera dome (just the one piece of plastic). So I just replaced the head with a plastic dome from a toy shop.

The result is not quite as fast as I would like, but it was unexpectedly charming.

Getting the arms to move.

A bracket was designed to get some cheap tower-pro servos to fit aligned with the arms. The brackets neatly affixes to old circuit mounting points in the plastic. A custom servo horn will friction fitted the arms to the servo. The existing arm bearing was sanded a bit to get it to slide freely. The result is a much more expressive robot.

Servo mount rear
Servo mount top
friction fit arm
servos installed
servo horns installed

Whats next.

I have made files for the progress thus far available via github, encase anyone has a Robie of their own and wants to try this. https://github.com/busyDuckman/robbie

Next up I will work on:

Drive system so Robie can move around.
Microphone array so voice interaction is possible.
Control software.
Personality and human interaction.

Parametric VESA Mount Fixer.

duckman — Mon, 20 Apr 2020 10:52:06 +0000

Recently I encountered a monitor that used a different mount positioning despite being only a few digits of in model number to its neighbour. The monitor needed to live with the other, sharing a horizontal mounting arm. I created an OpenSCAD mount to convert “lower mounted VESA”, to “central mounted VESA”.

VESA Mount Fixer (configurable)

You can download it via: https://www.thingiverse.com/thing:4300602

Background

Some manufactures put the VESA mount at the bottom of the screen, others in the middle. This can cause an issue for many situations, especially if monitors need to be used on a shared mount or in portrait mode.

Lets compare the pro’s cons of the mounting styles:

Feature	VESA Middle	VESA Bottom
Monitors line up nicely when sharing a mount.	Yes	No
Monitor is stable and does not roll violently on mount.	Yes	No
Monitor can be used in portrait mode without a rigid mount.	Yes	No
Monitor won’t drop forward overtime on an adjustable mount.	Yes	No
Mounting high on shop wall hides what is behind screen.	No	Yes
Monitor is cheaper to produce.	No	Yes

The result for a shared mount was quite noticeable.

Before
After

The plate which pokes out, should connect to the monitor. The other to the VESA mount (See below).

How it works.

Customisation

The mount can be customised in OpenSCAD, or via the Thingverse customiser: https://www.thingiverse.com/apps/customizer/run?thing_id=4300602.

CAD View.

The following parameters should be altered to suit your need.

Parameter	Values	Notes
correction		The distance to move the screen down.
washer_size		Creates pockets for washers and bolts to sit flush in. Use zero to disable.
connection_size	>=30 and <=100	The size by which the central column extends over the top of the VESA plate. Significant trade of between material use and strength. 30 produces a cheap print and holds light monitors. But 80 should be used for heavy displayed, or displays someone may pull downward on.
step	>=0 and <40ish	Total recess size (depth) of the adapter.
thickness	> 1 and <=step	Thickness of the VESA plate. This must be >= the depth of any pocket the vesa mount will sit in. Probably don’t go below 5 if 3D printing.

Spice Rack Plans (Woodworking)

duckman — Thu, 18 Jun 2015 17:37:07 +0000

This spice rack was my first CAD design for a CNC router build. The plans and effect were quite solid and people still remark on the unit, so I will share the design.

I originally designed this as a two shelf unit, but trivially built it as a three shelf unit. The indents in the shelf place McCormick brand spices (Australian jar) at a pleasing interval, and seat them snugly. The rail is at the right height to keep the label viable and support the jar, without making removal difficult.

Machining was done on the artifactory‘s CNC-router.

Final Result

Blue Prints

Image (click for larger)

Download

DXF (cad file) here

Construction Notes

NB: I could not quite let go of my old school woodworking tendencies, so I made all tabs fit the slots exactly… This meant that after the router made its cut, the wood would expand a little and not fit in the slot. This is just what I wanted, preferring a bit of sanding at the end, so all would fit very snug. Nowadays I would wind back the slots 0.3 of a millimetre and let the glue do the rest.

The spices escutcheons I ended up 3d – printing and painting. Nowadays there are plenty of 3d printing services should could offer a much better finish.

The stain I used was Wattyl Wood Gel – Honey Oak. I like how easy and fool proof these stains are. The results not bad either.

Photos of actual parts.