Sunday, October 26, 2014

Rietveld Steltman chairs

A friend of mine made a Rietveld Crate chair and I thought "Wow I want that too!". The chair looks great, but off course I thought "I can do that better" :-) Also, the chair is a bit big for my needs. So it reminded me of another asymmetric (almost mathematical) Rietveld chair: The Rietveld Steltman chair. Originally this chair was designed for a Jewelry shop (named Steltman) in the Hague and it had leather on it. There were two of them, mirrored versions of each other. The later wooden version was far more popular.  

After googling for dimensions I came across this blog from 'Rietveldbuilder'. He has exact dimensions of each part and also a drawing how to put the thing together. Great! 

I had a 'spare' table which I could use for this project. This could be my biggest "Ikea hack" ever. The Ikea BJÖRKUDDEN table, made of birch wood was 119cm x 74cm and it was 2.5cm thick. Hmmmm the original has parts of 4.4cm thick, that's a big difference. To fiddle a bit with dimensions I created a parametric 3D model on Thingiverse. It looked like the original is a bit big for me. Also with the thinner wood it didn't look quite as good. So I made it all smaller. The best of it all: I could make 2 of them from 1 tabletop!

The description also mentions mortise and tenon joints, but I didn't want to spend time on that. I decided to go for biscuit joints, fast and easy :-) The Lamello Classic X biscuit joiner did it job very well. The joints were created super accurate and it was very easily too.

Some tech details:
The 3D model gives me the following dimensions:
ECHO: "A", 44, 100, 600
ECHO: "B", 44, 100, 344
ECHO: "C", 44, 100, 456
ECHO: "D", 44, 100, 556
ECHO: "E", 44, 100, 400
ECHO: "F", 44, 100, 400
ECHO: "G", 44, 100, 256
ECHO: "H", 44, 356, 400

The model input (commented out are the original sizes):
THICKNESS = 25; // thickness of the material 44
WIDTH = 85; // width of most wood parts 100
HEIGHT = 690; // total chair height, default 700
F_LENGTH = 400; // seating height 400
H_WIDTH = 300; // seat 356
H_LENGTH = 337; // depth 400

Monday, August 18, 2014

Simple DIY Eurorack modules

First some pictures.

What you see is what you get:

Green: Slew limiter / portamento / glide. It limits the speed of change. It has a switch to limit up/down/both.

White: Passive OR-wired sockets. It is likely exactly the same as the Doepfer A-186. It combines up to 7 gate, trigger or analog signals by or-wiring. If all the inputs are low, the output is low. If one of them is high, the output is high. You can use this module to combine trigger signals. See the Doepfer DIY on how you can make this module.

White: Dual passive AND-wired sockets. A double 2-input, 1-output passive AND gate. If both of the inputs are high, the output is high. See Doepfer DIY on how to make this module.

Blue: Passive multiple, like the Doepfer A-180. Use this double 4-fold multiples to split some signal and route them to multiple destinations. For sensitive applications like a VCO a buffered multiple is recommended.

The front faces are 3d printed, models can be found at my Eurorack module thing at Thingiverse.

Saturday, May 17, 2014

Raspberry Pi based 4-player Arcade Maschine

Let me show some pictures and I'll tell something about them :-)

First of all, this is the "end product". Plug in the power and a joystick or two, turn it on, select a game and play right away. The box is completely self-contained: It houses a 14" lcd screen, a Raspberry Pi, an iPAC2 and 2 computer speakers. I managed to put it in a tilted box of about 36x35x16 cm (wxhxd).
The Arcade Maschine runs on Raspbian with PiPlay.

I used regular 15 pin VGA connectors for the joysticks. Easy plug in and pull out.

But the iPAC2 only supports 2 players, right? Only if you have a joystick (4 directions) and 10 buttons + coin + start = 16 buttons per player. Most 4 player games only have 2 action buttons. In this case you need only 8 buttons per player. The iPAC2 has 32 inputs, voila!

I wanted some arcade joysticks as well. This one on the left is mkII, made of 18mm plywood, 4mm plexiglass, Sanwa hardware. Great stuff! The buttons are very light. The Sanwa JLF feels very responsive.

And this is mkI. It is made with oak and some home brand hardware. It feels very solid. The stick is not as smooth as the Sanwa, but it works pretty good. The buttons use heavy duty microswitches, you need some pressure to activate it with a loud click.

And finally I also converted some "retro" controllers :-)

Update: Some tech details.
The box is made of 12mm birch plywood. It is quite some work using a plunge saw and glue.

I have chosen the dimensions so that all my second hand stuff will fit in nicely. Finally "taped" all things together with velcro, nice and easy!

From the drawing table
Internals: keep an eye on the wires!

Second hand speakers and screen