More DIY

...as you never dreamed in your worst nightmares

How to build an anticlock

An anticlock is a clock which goes the other way round - the hands move left instead of right, ie in the mathematically positive direction ;). Known for instance from Spider Robinson's "Callahan's Saloon", anticlocks cannot be bought in the shops. However, some clocks can be converted to anticlocks with little effort. Buy an inexpensive electrical clock (in case it doesn't work out) without numbers on its face. Some clocks (no garantees) work according to the principle displayed in the picture: A solenoid generates regular pulses of a magnetic field, which is added to the static field of its anchor, a quadrupole magnet. The small rotor, also a static quadrupole magnet, turns by 180 degrees with each pulse and thereby drives the clock. To reverse the direction of the rotation, remove the anchor, slip it out of the solenoid, flip it over left-to-right and mount it again.

Home-made bumper stickers

Wouldn't it be nice to be able to create one's own weatherproof stickers for use on the car, or one's front door? I used to make stickers by printing on paper and covering it with transparent adhesive foil. But over time, the foil invariably cracked, and rainwater seeped through and stained the paper - not an acceptable solution. I've since hit on something better: print on transparencies and attach them with double-sided adhesive foil. Printable transparencies usually have a rough side (which can be printed upon) and a smooth side. To obtain a durable sticker, it is important to mirror the design and print it on the rough side. This side is then stuck on one side of the adhesive foil, while the smooth side is exposed. The printed colours are therefore sealed by the adhesive and cannot be easily washed off. In my experience (with an inkjet printer), it is best to print in black and white only and fill in the colours by hand with a pen which does not bleach when exposed to sunlight.

It remains to obtain the double-sided adhesive foil. In my case, having a white car, transparent foil from my local handicraft shop was sufficient. Despite being in no way intended for that kind of use, it withstood all weathers and could even be removed easily after more than a year. If you want to attach a white sticker to a coloured car, you will have to obtain white (or coloured, if you prefer) double adhesive foil. There will be no guarantee that it works as well as the one I had the luck to obtain, so you might want to try a small piece of it out at an inconspicuous spot.

A low-budget acoustic ceiling

If you have ever bought or built high-quality audio speakers, you may have noticed that room resonances can significanly deteriorate their sound. This is especially true for living rooms in the "modern" design, without heavy upholstery and bookshelves. The professional solution to this problem is to put in a second ceiling made of acoustic panels with specific sound absorption properties. While the panels themselves are actually not terribly expensive, the metal rails which support them are elaborate and require perforating the ceiling with boreholes to fasten them. Putting them in will require your landlord's assent and the help of professionals who focus on business customers and price their services accordingly.

There is a way to solve these problems. Heavy textiles like curtains and carpets absorb high frequencies well, and low frequencies are best reduced by placing a second ceiling of whatever material at a short distance (20 to 30 cm) from the real ceiling. To combine these two properties, hang a carpet under the ceiling at that distance. The sort of carpet designed to be put in as a fixture is sold by the metre, and often cheaply if you are not after a fashionable design. For our purpose, it should be bright in colour (ideally white) so as not to darken the room too much. For fastening the carpet, I reinforced the corners by gripping them between a pair of flat metal pieces used for linking beams of wood. Small holes in the carpet for the screws can be made with a manual drill, while a big hole has to be cut out. This hole serves to take a wall hook (for two of the corners) or a cord fastened to a hook for tightening the carpet. The carpet will inevitably sag in the middle, but by lashing it tight, its distance to the ceiling can be kept between 15 and 30 cm, which is fine. The end fastened with wall hooks, if any, should be next to your speakers, since the distance to the ceiling will be easiest to fix at that end and unwanted bass resonances tend to involve standing waves between floor and ceiling at the speakers.