Here is a nice followup to yesterday’s video: How to make your own ferrofluid. This guide comes from Dr. Anne Marie Helmenstine at About.com The fine folks at Sci-spot seem to have the original with pictures. The composition of ferrofluid by volume is about 5% magnetic solids, 10% surfactant, and 85% carrier. The surfactant is what keeps the particles from sticking together permanently. Ferrofluids are often used for damping speakers and in disk drives. This procedure doesn’t seem to complex and one of the main components is ferric chloride, a.k.a. PCB etchant. Thanks go to [Jason Uher] who sent in this tip and says that it has worked out quite well for him in the past.

[photo credit]

Continue reading “Make Your Own Liquid Magnets” →

[Alan] from Hacked Gadgets put this Bawls automatic light together pretty quickly. He used a photocell, transistor, LED, and a 9V battery to make it turn on automatically when the lights go out. It creates a nice eerie blue glow. You might remember that he isn’t the first Hack-A-Day reader to get lured in by the Bawls lamp. [Chris] made a cold cathode Bawls lamp last fall. I found this picture on ZapWizard’s photostream as well.

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imakeprojects.com started recently with the promise of delivering one project every two weeks. Yesterday was their second release: sonic grenades! They picked up a couple 110dB personal alarms at the Dollar Store and modified them. Now instead of going off immediately, there is a 5 second “fuse” indicated by a flashing LED; giving you plenty of time to lob it into your roommates space. After a minute of being active, the grenade will start chirping every 10 seconds until you replace the pin which should help you find it. There’s a video demo at the bottom of the page.

[thanks JErome]

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Reversing the lens orientation is common practice in macro photography. To get even more magnification you can increase the distance between the film and lens by using an extension tube or bellows. [Kevin] built this variable length extension tube by modifying a bunch of cheap used filters. When I say “modify” I mean he “broke the glass out with a hammer”. The base of the extension tube is a body cap that has had the center removed. Glued on top of body cap is a filter ring with the male threads pointing forward to act as the reverse lens mount. You can add any number of additional rings to change the length. It’s very important to be thorough when cleaning your filter rings otherwise you might damage your camera internals.

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[Laurens Tromp] stumbled upon this LED lamp project while looking for a datasheet. The lamp has two heads with 252 LEDs each. The individual heads have equal number of red, blue, green, yellow and white LEDs. At the base of the lamp is a touch pad that has a virtual slider for each individual color’s intensity. The heads can be controlled separately or together. The lamp can also be operated over ethernet since its controller is a RabbitCore RCM2200. The only answer I can’t seem to find in the extensive documentation is how much this milled aluminum monstrosity weighs: 110 pounds.

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The Cisco Unified IP Phone 7960G is becoming fairly common in corporate environments. The phone has a built in XML browser for navigating menus. [Nick] decided to hack together a PHP application that will let the phone display email messages in a POP3 account. In its current form it works with most text-only messages, but limited filtering means it could fail on some.

Continue reading “Email On The Cisco 7960” →

Humans exhale a lot of oxygen along with their waste carbon dioxide. Instead of throwing out this oxygen, a rebreather uses a scrubber to remove the CO2 and replace it with pure oxygen from a bottle. Tom Rose built this rebreather for $100. When you exhale air passes through the scrubbing material and is stored in hot water bottle counterlung until you inhale. The system is only 15 pounds; a great savings compared to most dive equipment. You are definitely putting your life in your own hands so this should not be used without plenty of “couch-diving” tests. Tom has a ton of other diving related projects on his site.

[via Divester]

Continue reading “$100 Hot Water Bottle Pendulum Rebreather” →