Building a home robot: Part 3 - the chassis

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If you want to build an autonomous robot there are at least two things to solve: Battery power and automatic charging.
Nobody wants to build a robot which needs to be charged by hand.  But building and programming a chassis that can find its docking station and charge automatic is complex and/or expensive.

So it is great that there is an existing consumer product you can use: The roomba vacuum robot from iRobot. You can get a used one for round about 150 €. If its vacuum or brush unit is broken it may cost less - and you don’t need these units.

The Roomba also supports an official and well documented serial port to control it and read its sensors.

So for my robot project I used an old iRobot Roomba.It was originally white color – but after some years of usage and sunlight some sort of ugly yellow instead.

To refurbish it I sanded it, painted it in my favorite color and bought a new battery.

In my case I wanted to use MakerBeans to build the main body of the home robot. So I mounted a small base of MakerBeans to the iRobot chassis. 

To find Roombas serial port you have to remove the robots cover. Next to the serial port there are some screws you can use to attach your own robot parts to the chassis:



Building a home robot: Part 1 - introduction and head

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Since I was a child and saw the tomy omnibot I was fascinated about robot companions. In the following years I took some tries to get or build one – for example the Sony Aibo in 2001 or my Cobra Robot.

Some weeks ago I started my first serious project of a self driving, self charging home robot - including things like face detection and voice output.

My girlfriend was not sure if it would be a little bit scary to live together with a home robot. So I decided to create a first prank design for the robot head especially for her ;-)

(A scary prank design created from old animatronics parts)

The real head will be much more cute and abstract, using a small monitor instead of physical eyeballs.

As the robot “brain” I choose a Raspberry PI 3 because it is small, fast and with low power consumption.  Other reasons were: cheap and native camera, hardware connections via the PIO port and the available official touchscreen monitor.

To create most of the body parts I want to use my 3D printer.

In the past I often used 3d editor programs like Autodesk 3D Studio or Cinema 4D – but never real CAD programs. After some research for a low cost but useful CAD program I found OpenSCAD.

This free open source tool and its unusual approach to create objects by writing program code suits perfect to my needs.

Only 3 hours later I had finished my first CAD model of a head prototype and started the 3d printer. (I plan to upload all the STL files to to share them with other makers who want to built their own home robots)

The first prototype of the robot front head:

The following 4 improved prototypes:

An early prototype showing the complete head shape:

The final front part without raspberry pi...

...and with raspberry pi and the touchscreen monitor:

The next step will be the neck design and the motors for moving the head and the neck.

Continue reading: Part 2 - Neck design and movement

Ultimaker 2+ arrived

Seven years ago in 2009 I started my first experiences with 3d printing.

It took 2 weeks to assemble my first 3d printer – a rapman from UK. It had no heated built plate and the software needed lot of tuning and testing.

The rapman in 2009:

Then in 2011 I got the makerbot thing-o-matic. It had a heated, automated build platform and only took 2 days to assemble. The software still needed time to tune and to find out the best setting.

All this time I never managed to get PLA printing well – only ABS worked fine for me.

The makerbot in 2011:

Yesterday – 5 years after the makerbot – my ultimaker 3d printer arrived.
In my opinion there are worlds between these two last devices.
The ultimaker looks like from the future with its white led lighted housing, while the makerbot looks like from the past with his wooden case.
The ultimaker prints a lot of finer and more silent than my old makerbot.
No (or only a little bit) software tuning is needed– it is nearly plug and print.
It is very impressive for me to see, how big the improvements of these 5 years are.

Here are some impressions:

Maker Faire 2013 in Hannover

Die Maker Faire am vergangenen Wochenende in Hannover war – abgesehen von den unmenschlich heißen Temperaturen in der Halle – ein prima Erlebnis. Wenn man mal von den zig Derivaten an 3D-Druckern absieht, gab es für mich viele Anregungen.

Sehr toll fand ich das Hacklace, eine Art digitaler Kettenanhänger. Dieses kann man sich entweder komplett selbst zusammen bauen (die Pläne sind open source) oder für günstige 10 EUR als Bausatz bestellen. Ich habe mir direkt einen der Bausätze gekauft, der sich in 15 Minuten zusammen löten lässt. Ich bin immer noch ganz angetan davon – es ist ein netter Hingucker.

Das Hacklace in Aktion

Neben ganzen Projekten gab es auch einige Stände mit Roh-Materialien. Zwei davon fand ich besonders interessant:

Viel versprechend und preislich auch recht attraktiv sahen die Aluminium Profile „MakerBeam“ aus, wenn man mal einen stabilen Testaufbau zusammen bauen möchte.

MakerBeam Alu Profile
Ein MakerBeam Starter Kit

Ein Schlitten konstruiert aus Alu Profilen mit Kugellagern - MakerBeam Alu Profile
Ein Schlitten konstruiert aus Alu Profilen mit Kugellagern

Ein kompletter Versuchsaufbau mit Alu Profilen - MakerBeam Alu Profile
Ein kompletter Versuchsaufbau mit Alu Profilen

Unschön beim Lasern von dünneren Holzplatten sind oft die rußigen Ränder. Auf einem Stand der Maker Faire wurde das Produkt kraftplex vorgestellt. Die in 1mm und 0.8mm Stärke erhältlichen Platten bestehen aus reiner Holzfaser, bekommen beim Lasern aber keine russigen Ränder. Dazu sind sie noch recht stabil und dennoch flexibel. Ich konnte noch auf der Messe zwei kleine Muster mitnehmen, die bereits viel versprechend sind.

Zum Schluss noch ein paar Impressionen:

Maker Faire 2013 in Hannover

Maker Faire 2013 in Hannover

Maker Faire 2013 in Hannover

Maker Faire 2013 in Hannover

Maker Faire 2013 in Hannover

Maker Faire 2013 in Hannover
Ein Steam-Punk Notebook

Maker Faire 2013 in Hannover

Maker Faire 2013 in Hannover

Maker Faire 2013 in Hannover
Ein Steam-Punk PC

Maker Faire 2013 in Hannover