Plasteac – Enhancements

You must remember my cute robotic dancing teapot. It works great, but it has a little drawback: you need to open it to physically connect and disconnect the battery. Therefore, let’s fix that issue by integrating a switch directly in the teapot lid!

I designed three new plastic parts for the second version of the lid. The new lid features a hole instead of the handle, and the actual handle is to be glued to an axis going through the lid, with an elliptic lever at the bottom. The lever shall push a micro switch attached on the inside of the lid, just like you would press a button.

The three new parts: the lid with a hole, the handle, and the button switch
The three new parts: the lid with a hole, the handle, and the button switch

You can download the new SCAD source files (licensed under GPLv3) and the corresponding STL files on my GitHub repository. Apart from a micro switch, I’ll also use prototype board, pins, and a Dupont wire.

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Plasteac: a dancing teapot

The Bob robot, itself remixed from the Arduped robot, inspired an impressive number of clones with its really good design.

The most famous ones might be Zowi, and more recently Otto. They are both simple, cheap, open-source and 3D-printed little robots which have refined Bob two-legged design.

Yet, I am not a fan of their strange square heads. What I would like is a teapot. A dancing teapot.

I chose to design 3D-printed parts from scratch, not only because I prefer to use OpenSCAD over FreeCAD, but also because the design of the top part will be entierly different anyway. Also, for once, it will be powered by a 9-volt alkaline battery rather than a lipo battery.

3D models forming the robotic teapot
3D models forming the robotic teapot

You can download the SCAD source files (licensed under GPLv3) and the corresponding STL files here or on my GitHub repository. I printed them with white PLA, not the fanciest color but the perfect one for a teapot.

The components are ready to assemble.
The components are ready to assemble.

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A telepresence robot – Building

Telepresence robots are pretty cool, so let’s build my own Telebot!

The telepresence robot allows visioconferencing while moving around
The telepresence robot allows visioconferencing while moving around

The robot will be built as a base with 4 wheels, on top of which a vertical pole allows to stick a smartphone. The smartphone, connected to the base via Bluetooth, will permit visioconference via WebRTC and remote control at the same time, allowing to move around. Even if the center of gravity is quite high, a gyroscope will prevent the robot from falling over. The base will be powered by lithium-polymer batteries and rechargeable via a USB connector.

The finished robot going around

This article covers building the robot, while the next article focuses on programming it.

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A small 3D-printed NAS

Network-Attached Storages (NAS) are very handy devices on a home network. They offer a simple way to share or synchronize files, and can host various useful services at the same time provided they are generic enough. A NAS being nothing more than a specialized file server, we will actually build a small home server than will be able to do anything.

The functions can be the following:

  • File server (FTP, NFS, SMB/CIFS…)
  • Streaming server (audio or video on the local network)
  • Personal web server (to host a website, synchonize contacts or send files to people)
  • Local seedbox (to download torrent files)
  • Domotic hub (for instance by adding a Zigbee USB dongle)

The server will be pretty simple in its technical design: a Raspberry Pi 2 model B with two hard disks connected with USB adapters.

The Raspberry Pi is actually not able to power the two drives over USB, since we would need 500mA per drive, so 1000mA overall, and the Pi can only supply 600mA over USB. There is a possible boot setting in /boot/config.txt called max_usb_current, which when set to 1 raises the maximum current intensity over USB to 1.2A, but since it is applied only during boot, our disks will still prevent the Pi to actually start properly. For this reason, we need a USB hub with a 2A adapter to power everything and connect the drives to the Pi. Backfeeding would be quite a bad idea, so the Pi needs to be connected to the hub twice, once as a device for power and once as the host.

In this kind of setup, always pay attention to use a genuine power adapter that will be able to handle the load, some really cheap adapters are rated 2A but might not be able to supply this current over a long period of time due to overheating.

I designed the case, front panel and lid with OpenSCAD to print them in 3D. You can download the SCAD source files and the corresponding STL files here (licensed under GPLv3).

3D models of the case, the front panel and the lid generated with OpenSCAD
3D models of the case, the front panel and the lid generated with OpenSCAD

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