Archive for March, 2009

Hardware is fun: Two HOWTOs

Monday, March 16th, 2009

How to build a Do-It-Yourself beamer

Nowadays, everybody has a home theater. Most people pay lots of money and don’t have fun. We paid almost no money (300 €) and had lots of fun.

Signal source:

  1. Get an old and silent computer on eBay. VGA is enough. We got a HP Vectra VL400.
  2. Get a good and old PCI  sound card with 4.1 or 6.1 with proper Linux driver support. We got an SB Live!
  3. Use a VDR distribution like easyVDR, assuming you also want to watch DVB or simply use mplayer on the console with the frame buffer.
  4. Assuming you use VDR, hack FBTV to center your image on the framebuffer and do deinterlacing [patchset found via google]. Ensure that you have a 1:1 mapping between signal source (PAL TV or anamorphic DVDs in my case), and the screen pixels.

Video:

  1. Get an old overhead projector, 4000 ANSI lumen or more. Mine is a 3M 1750 with suboptimal but cheap halogen lamps.
  2. Get an old robust TFT monitor, and remove the panel from the electronics. Mine is a EIZO L365.
  3. Build a mask from cardboard in adequate size and put it on the OHP
  4. Build two parallel spacers from wood and put them between the cardborad and the TFT
  5. Get a tangential fan that can be built into a slot, and put it from the side between the panel and the OHP
  6. Get a cheap used but quality projection canvas. Don’t use eBay, usually they are to expensive. In Germany, you can use quoka.de to find cheap ones. We got a Stumpfl AV 1:1 4 m^2. If you don’t find any, build it yourself. The most important thing would be a planar framing, and a proper canvas. In Central Europe, I can recommend boesner.com for the frame, and gerriets.de for a molleton base layer followed by a reflective foil layer.

Audio:

  1. Get an old but very good and defective audio amplifier on eBay. The Grundig V5000 is amazing, really! For 4.1 or 6.1, you’ll need two or three of them because in the 80s, they “just” needed Stereo.
  2. Know somebody with adequate electronic skills for repairing it, or repair it yourself.

Now: Have fun! A classical 80/20 solution: (even less than) 20% of the (financial) complexity and 80% of the optimum result – achievable with 10000 € or more.

Possibly related:

How to reconstruct broken mechanical components from some random hardware

  1. Be upset that knob X or handle Y is not produced or shipped anymore by any support in the world
  2. Find a skillful model building company which does prototype development – so they make also small batches (say, 1)
  3. Use a CAD tool like CATIA, and construct the mechanical component on your computer. Use a (digital) sliding caliper, and work at least to 1/10 mm.
  4. Give the CAD construction to the model builders who have CNCs or do rapid prototyping for you.

Now: Be totally happy that you got your component! :)

I hope this animated everybody who totally focused on software to also consider hardware recompilation. It’s fun, really :).