1000W Search Light – Now Build A Bat Signal

October 22, 2010 by Mike Szczys 41 Comments

Forget flashlights, and leave those burning lasers at home, [Ben Krasnow] built a search light using a 1000W xenon arc lamp. That box you see on the side of the trash-can housing countains a starting circuit that shoots 30 kilovolts through the xenon lamp to get it started but it is separate from the power supply. [Ben] started experimenting with the lamp back in April but recently finished the project by using the inverter from an arc welder to get the 50 amps at 20 volts needed when the lamp is on.

The insert on the left of the image above is an outdoor picture of the beam. You can make out a tree at the bottom. Take a look at the video after the break for a full walk-through of the circuitry and some test footage of the finished product.

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Tiny FM Transmitter Bugs Rooms

October 21, 2010 by Mike Szczys 30 Comments

Lucid Science delves into spy-tech once again with this tiny FM transmitter. Their post demonstrates a bit larger version than seen above, using a 9-volt battery and protoboard sized to match which makes for easier soldering. The design uses a microphone, two transistors, enameled wire for the coil, as well as various resistors, capacitors, and a potentiometer. What you end up with is an amazingly clear audio signal that can be picked up with a normal FM radio.

This would make a great project to do with the kids. You can talk about circuit design, practice soldering, and when finished they’ve got an almost miraculous toy to play with. Just be careful what you say around the house, the room might be bugged!

Multiple Core Propeller Speeds Up Display Addressing

October 21, 2010 by Mike Szczys 22 Comments

If you ever wondered what an eight-core Propeller processor can do for you, [Tom] found one answer. He’s using the multiple cores to individually address serial displays. He has six display modules, and each of them incorporate six 8×8 LED modules. This makes for a total of 2304 LEDs, and since they’re addressed by cascading serial data, that means 2304 bytes pushed to the display. You’re going to suffer from quite a bit of slow-down if you choose that communication method.

This is where multiple-cores come in handy. Instead of cascading data between the six modules, he assigned a different core to each. Now he can concurrently address the six displays, reducing his serial data from 2304 bits per frame down to 384 bits per frame. As you can see in the video after the break, updating the display six times as fast as before yields fantastic results.

Now what if you’re using a processor that has forty of these multi-core Propeller chips?

This does make us wonder, can’t the same thing be done on a single-core processor? An eight-bit device takes one cycle to set all eight bits on a single port. So why not just connect the six serial connections on six bits of the same port? Weigh in with your thoughts in the comments.

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UV EPROM Eraser In A Toolbox

October 21, 2010 by Mike Szczys 20 Comments

[Devon Croy] belongs to a hackerspace that works hard to keep hardware from going to the landfill. He found they were in possession of over a hundred Erasable Programmable Read Only Memory chips (EPROM). Not to be confused with EEPROM, which are electronically erasable, these EPROM chips require a strong source of UV light to blank the old data before they can be written again.

Instead of buying a tool to erase two or three chips at a time he built his own bulk EPROM eraser from an old metal toolbox. He used parts from a fluorescent black light and acquired a new bulb that generates light in the UVC spectrum, the band which works as an eraser for the chips. After bolting the parts into the case he added a spring-loaded timer knob and a safety switch that kills the power when the case is opened, similar to the UV exposure box we looked at yesterday.

Of course, if you don’t need a bulk eraser you could shop some garage sales for a UV pacifier cleaner which can also erase EPROM chips.

90 TB Drive Array For Home Storage Needs

October 21, 2010 by Mike Szczys 53 Comments

Why store it in the cloud when you could have a 90 Terabyte hard drive (translated) array in your house? The drives are mostly Western Digital Caviar Green EARS 2TB models which are known for energy efficiency and quiet operation. It’s a little unclear as to whether this is using one or two motherboards, but the drives are connected using PCI RAID5 and RAID5+0 controller cards. There’s a total of 40 cooling fans built into the case, half on the bottom and the rest on the top. They move air up through the case, with plans to add a dust filter in the future. Heck, with that type of air movement you could throw on a standard furnace filter. Apparently it is quiet enough to talk in “almost a whisper” while next to the plywood monolith. But we’re a bit skeptical of that claim.

It’s not quite as fancy looking as the 67 TB storage from last year… but it does look pretty easy to build at home.

[Thanks Henrique via EnglishRussia]

AVR DDS Signal Generator Improvements

October 20, 2010 by Mike Szczys 11 Comments

[Vassilis Papanikolaou] took a good thing and made it better with some design upgrades to this AVR based signal generator. We looked at version 1.0 of this tool back in 2006 and since then it saw an upgrade to 2.0. But [Vassilis] wanted to take things one step further, with a compact single-sided PCB. What you see above is the beautiful result of his work; a professionally made board that is compact, uses through-hole components, and has zero wire jumpers.

If you want to build one for yourself there’s a great parts list as well as board artwork and schematic. The system uses an ATmega16 so you’ll need a way to program one. There’s also just a bit of firmware tweaking to remap the control buttons to match the updated hardware layout.

Building A UV Exposure Box

October 20, 2010 by Mike Szczys 29 Comments

There are two methods of using etchant resist when making circuit boards. We use the toner transfer method that requires ironing on laser toner to the copper, but you can also use chemical resist that reacts to ultraviolet light. [Bogdan] decided to start doing more of the latter so he built a UV exposure box to make the process easier.

It is possible to use flourescent light bulbs for this, but he decided to use UV LEDs, a method we’ve also seen before. But there’s always room to innovate, and [Bogdan] built-in a couple of nice features that are new to us. Because the UV light can be bad for your eyes, he included a set of red visible-light LEDs on the bottom half of the box that are used to align two layers of exposure mask when making double-sided boards. There’s also a switch that automatically shuts off the UV light when the box is opened. And as the coup-de-grace, he added a programmable timer to regulate the exposure, using his newly created box when etching the PCB for it.