Assorted Metal Stuffs
Some fun on the CNC and manual lathes, 3-axis CNC mill, water jet, etc... Most of it's for a friend's desk light (the U-channel will encase a strip of LEDs, suspended by a ball-socket arm fixture), some of it's just for fun. Enjoy the photoshop-sharpened, cell-phone-camera-snapped fuzziness made even better by taking through foggy, coolant-splattered safety shields...
The bar stock is 303; plate is 304 SS.
Rough pass #1
Rough pass #2 or 3
Rough pass #4
Left side finished, stem now in collet.
Getting slightly spherical...
More spherical...
Almost spherical...
Spherical.
Not shown: internally tapping the stem of the ball.
Putting a #4 brushed finish on SS tube (left, before; right, after). Bit hard to tell in the pic.
Profile of lamp head. LEDs go in the track; ball goes in the tube I was finishing in the pic above.
Mounting part of the second ball join for threading. This one got external threads (big, too... 5/16-24), whereas the other got internals. Notice the groove partway down the shaft. This is a zero-indexing mark for the other half of the sphere.
Cutting threads.
Final pic. Will post a better pic with a real camera soon.
Building a French-Style Harpsichord After Henri Hemsch
Please see http://hemsch.blogspot.com. This project is now terminated due to tremendous cost associated with shipping it home (I'm about to graduate 2500 miles from home) and realization that I could start over and do it twice as well in half the time. If you are in the Boston area and want a skeleton that looks like a harpsichord, but does not play, let me know, you can have it.
Homebrew Whole-House Audio Systems
My parents wanted music throughout their house, but wanted a simple system for under a thousand dollars. This basically ruled out commercial systems. I'm quite familiar with Crestron, a leading name in this sort of thing, having dealt with their systems at MIT extensively. These systems would allow different audio sources to be played in different rooms and provide touch-panel interfaces... they'd also control your window coverings and fireplaces and pretty much anything else you want. I think their number of customers compared to the amount of product development they must do to keep their products current is small; this option would have been easily above $10-20k.
Instead I evaluated a few alternatives. First I looked at buying an FM transmitter (circa 50 mW), but I couldn’t find any I liked for sale under a few hundred dollars, and I didn’t want to take the time to make one (nor was I confident that mine would be high fidelity). The benefit of an FM transmitter, though, is that any radio could have tuned in, so we could move the sound anywhere we wanted, when we wanted, inside or out.
So I instead settled on a high-power speaker network. The design only allows one sound source to be played throughout the whole system, but does have individual volume controls in each room. My system is basically:
1. 4 speakers downstairs (2 in-wall, 2 satellites hidden) (wired in series)
2. 4 speakers for the lower outside area (water-proof satellite speakers) (wired in parallel)
3. 6 speakers in the master bedroom and bathrooms (all in-ceiling) (wired in series)
4. 2 existing satellite speakers tied in from the home theater system, on a sound-activated source switch
5. 2 speakers in the laundry room
6. 2 speakers in the office and 2 on the spa deck outside (wired in parallel)
Each group is wired to an individual volume control which multiplies the impedance by 8x. Each volume control is wired to a 1000 watt amplifier in parallel. My amplifier's minimum impedance is 4 ohms, which is why several zones are wired in series. So my system is about 4-5 ohms total. The bedroom zone, though, is 192 ohms alone! Designing this system so that the impedance was balanced properly took a bit of work, but was the only way to do this with one amplifier.
The fancy next-step in the home-brew realm would be to get a splitter-router-mixer (e.g. the now-defunct Rane SRM66) and one amplifier per room/zone. This would allow you to have multiple input sources and multiple amplifiers, routed to each other in any combination you want. The Rane units have interfaces for wired (and now, probably wireless) remotes that can change "scenes" (stored programs of source-output combos). Back to this setup:
All volume controls, wire and speakers came to a mere $415. The speakers were very cheap (satellites for about $15 each, in-ceiling for $5 each, shipped, from some no-name company), and had an OK frequency response (40Hz—20kHz says the box). Sound quality in person is OK, but not as good as Bose or JBL by any means. Fine for background music. Biggest thing I don’t like about them is that they are quiet. I don’t know why they are — if they have inefficient transducers, bad crossovers, or what. My amp has to be turned up quite high to put out normal listening volume. (With my big DJ speakers, I only need to run the amp and system around 20% for normal volume; now I run it around three fold higher to get the same volume from one pair connected directly to the amp.)
Wiring was a pain. Speaker-level cable had to be run from one central location to all the volume control locations, and from each volume control to each speaker. Also had to make a cable for line level transmission of the audio from my parent’s computer to the amplifier. By having all the speaker cables terminate at one central location, however, this would allow multiple amplifiers to be installed later so that each room could have its own audio source.
I made wood boxes around the ceiling speakers by adding 2x6s between the rafters and closing off with plywood. This helped with the sound quality/quantity a lot and was easy to do.
So, this system does exactly what they needed: allows them to play music throughout the house, and I did it for under $500 (though I already had the amplifier and other line-level audio equipment). Not terribly difficult, and definitely cheaper than a pro would charge.