Year: 2010

Building A Power Supply Around A DC-DC Converter

September 12, 2010 by 15 Comments

The EEVblog is on a roll with interesting topics lately. In the latest episode [Dave] takes us through the nitty-gritty of switch mode power supply design. Using DC-DC converter IC’s in not especially hard. The datasheets tend to have fairly good usage schematics but there’s always a bit of heartache that goes into figuring out which external components will make for an optimal design. Get your calculator out and, in the video after the break, he’ll walk you through choosing component values based on the formulas for the MC34063 converter chip.

[Dave] makes the point that this is an extremely common chip, available from several manufacturers, and often found in consumer electronics. In fact, the switchmode supply hack from last month was using a regulator based around the MC34063. So you can buy it or scavenge for it. One thing to note though, we checked Mouser and Digikey and they’re pretty short on these chips right now. Plan your projects accordingly.

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Small CNC Gadget Draws What It Hears

September 12, 2010 by 7 Comments

This art piece makes drawings based on sound. [Mario Marchese], who is responsible for those illusion props back in february, built this little guy out of a bunch of junk he had lying around. It features four microphones that listen to ambient sound and feed the signal through some LM386 audio power amplifiers. The output is translated into forward, backward, left, and right movements of the writing platform while the pen is fixed in the same position. Despite what we said in the title of the post this isn’t strictly a CNC machine, but more the primordial cousin of one.

Cheap Cable Reused To Add USB To Your Project

September 11, 2010 by 39 Comments

You get what you pay for. [Jkx] wanted to see how a USB to RS232 cable could be sold for just $1.70 and found out that it’s not actually RS232 compliant. The cable communicated as TTL levels, not the 12V expected of RS232 (although it can handle 12V incoming). He didn’t really want to use them for their intended purpose anyway. By betting rid of the DB9 plug and reusing the enclosed circuit board he now has a really cheap way to interface a microcontroller with the Universal Serial Bus. He worked out a couple of short subroutines that take care of receiving and sending data over the connection.

Keypad Door Lock, Better Than Last Years Keyfob?

September 11, 2010 by 13 Comments

It’s that time of the year again. The leaves are changing colors, it’s getting colder outside, and all the littler hackers are off to college. Which means we get to see an influx of dorm room locks and openers.

[Adam] is back at it again with a new keypad dorm room lock. Last year he had an exceptional setup using a car keyfob, so we’re a little curious as to why he would revert to such a low level system as a keypad that isn’t even color coded.

Perhaps its in his “new” way of presenting the hack. Rather than a blog or write up, he documents the entire most of the process in a little less than 20 YouTube videos. Watch him testing out the system after the jump.

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Macro Lens For A Nexus One

September 11, 2010 by 14 Comments

[Thomas] tipped us off about a macro lens attachment for his Nexus One. As you’d expect, adding the lens helps the phone’s camera bring tiny details into focus. He re-purposed a lens from a pair of mini binoculars, using epoxy putty to make a mounting bracket. Now the last time we saw this putty used with a phone it was for a snap-in bracket that cradled the phone and included a lens adapter. Rather than go that route [Thomas] made use of the headphone jack just above the camera lens. An old headphone plug has been epoxied to the macro lens ring, holding it in place securely while remaining easily removable.

Internet Controlled Remote

September 10, 2010 by 41 Comments

How often does this happen to you? You’re leaving on a long trip, and half way there you remember the TV was left on. Never? Alright then, how about wanting to control an Xbox 360 from within the other room and you don’t have the remote. Still a rare occurrence?

Perhaps you have a better situation where an internet controlled IR remote, that can be programmed to work with any TV or IR accepting device, would be useful. [Nicholas McClanahan] starts off with USB Propeller from Parallax, adds an Ethernet module making a mini server, and ends with an IR LED and receiver. The code is nearly as simple being a combination of SPIN, Html, and JavaScript. All coming together under a nice website GUI that prompts for what IR signals to send. To make the project even more straightforward, [Nicholas] has included an Instructable as well. In the end though, while the hack is great, we’re still trying to find a decent enough use. Video after the rift.

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PVC Pipe Fittings Just For Building Stuff

September 10, 2010 by 50 Comments
If you’ve used PVC as a building material in your projects you may have run into trouble finding a way to make three pipes joint at right angles to each other (like the corner of a box outline). That’s because there’s no need for that type of joint when plumbing, the intended purpose of the PVC pipes. But [John] tipped us off about FORMUFIT PVC Fittings designed for construction use instead of plumbing. There’s a lot of interesting options, such as the ninety degree connectors, rounded end caps for aesthetics, and end caps designed to receive casters. We also enjoyed seeing the T connector that slides onto a pipe and can function as a swivel. We haven’t tried them out ourselves, but we think they’d come in hand whether you’re building complicated moving structures or just making a desk.