By Collin Allen

Mac Mini Projects

June 21, 2005

If you recently got a Mac Mini and are still looking for something useful to do with it, aside from using it as a normal desktop computer, here are 50 Mac Mini projects to keep you busy. Useful purposes include web and mail servers, firewalls, backup servers, and media players. The Mini fits into the server category very well, considering it’s lack of a built-in display, as well as it’s FireWire connectivity. If you’re looking for a technical summer project involving everyone’s favorite “headless iMac,” that’s the place to start.

Backing Up GPS Maps

June 21, 2005

Recently I got a Garmin iQue 3600 GPS/PDA. I like it a lot because it runs Palm OS, has GPS capabilities, and also doesn’t lock out off-the-shelf SD cards for map storage. To store more maps than I’ll probably ever need, I purchased a 1 GB SD card to go with it, which it happily formatted and took advantage of. I also used the SD card for a short period in my Minolta Dimage G500. I like having plenty of storage in both devices, and wished there was an easy way to swap the card back and forth. I could just let my camera erase the card, and then re-download the maps onto it when I need them, but that requires Windows and about an hour and a half of my time – probably much longer running Virtual PC, as opposed to a real PC.

I discovered that I could read the SD card in it’s map-storing state via a PCMCIA card reader, and I imagine any SD capable adapter would allow the same. The iQue formats the SD card as FAT16, and Mac OS X is able to read it. Using Disk Utility, it’s easy to create a new image of the card onto my hard drive by selecting the device and choosing New, Image From disk2 (where disk2 is the Unix device for the card). With a 1:1 duplicate of the SD card’s maps on my hard drive as a read-only disk image, the card can be reformatted for use in my digital camera. When I want to quickly load the maps back onto the card, I plug it in and restore the .dmg file back to the card. Now I can swap the card back and forth while on the road without having to wait an hour, or use Windows.


June 20, 2005

Things have been a little slow around here because I’ve been dedicating a bunch of time to my latest project – disassembling a grape iMac and fitting its parts into an LC III case. I’m finally done now and am happy to report that it was a complete success. It required more hardware modification than I had initially anticipated, and I ran into some problems along the way, but without those troubles I wouldn’t have made it to this point. What follows is a step-by-step of what I did to cram a big gumdrop shaped iMac into a pizza box sized LC III case.

Several weeks ago I received a dead grape iMac from a MUG member who suspected that the power supply had bitten the dust. I had previously agreed that I would take the iMac in trade for retrieving the files off of the hard drive…which was a fairly easy task thanks to an IDE-to-FireWire bridge out of a hard drive enclosure. Since the power supply was useless, I couldn’t easily tell what else on the iMac worked. I disassembled the candy colored machine and salvaged the logic board, video board, speakers, microphone board, hard drive, and case. With all the major useful components laid out, I set to doing a little research on the net.

I found several useful iMac hack pages, including one (saved copy) which detailed the power connector on the bottom of the iMac’s logic board. Attached to the board is a power filter, likely because the power supply is very close to the (electrically) noisy cathode ray tube inside the iMac case. Since I wouldn’t be using the same physical configuration, it most likely wasn’t necessary.

Digging around in my array of old computers, I found a Macintosh LC III which no longer worked. I decided to challenge myself and see if I could fit the iMac’s components into it. The LC III is a dream to take apart compared to the iMac – the back of the case has one screw, then two snaps. The top then easily lifts off to reveal all the parts. Since the LC III was already defunct, I just removed all the parts from the case and set them aside.

I began placing the iMac’s components into the LC III case to get a general idea of where they might fit. As far as I could tell, all the parts would fit within the area of the case, but height was another issue. The case only provides a little over an inch of vertical space, so I had to keep everything very low profile.

imac lc iii top open

The first issue I ran into was power. Since the iMac’s power supply was dead, I couldn’t use it’s board, not to mention the fact that it was gigantic and would take up far too much space. On the iMac to ATX conversion page I found earlier, the author detailed how to adapt a standard PC ATX power supply to an iMac. Following his diagrams, I built a small adapter with a female plug and pin header, which would connect an ATX power supply to the bottom of the iMac’s logic board. With the adapter built, I carefully checked my connections – you only get one shot with this type of work. Borrowing a spare ATX power supply, I powered up the iMac logic board. While it had no magnetic or optical drives connected, it still made the familiar Mac startup chime and displayed a blinking question mark, indicating it could not find a system folder to use. I’d never been so happy to see that symbol before. I quickly powered it down and attached the iMac’s CD-ROM and let it start Mac OS X 10.3.5, which also booted just as easily.

imac lc iii atx adapter

After having complete success with the logic board and power supply, I moved on to the optical drive with a good feeling that I may actually accomplish something with this project. I noticed that the LC III had a lot of spare room around the floppy drive, and I thought it would be a perfect spot for a CD drive. However, the slot facing the front wasn’t wide enough for a CD. With a little filing and sanding, the slot was wide enough to accept any disc, and has the benefit of still looking stock to the untrained eye. After that, I spent the next few hours modifying a slot-loading DVD-ROM so that it sat at the proper height to catch an inserted CD or DVD. The hard drive would stay in the same cradle as it was in the original LC III design, and required no modification to make it fit.

imac lc iii ide cables

The biggest task in this project was to clear out most of the raised plastic squares on the bottom of the LC III case to gain an extra quarter of an inch under the motherboard and power supply. Between Dremel grinding wheels, pliers, and some sandpaper, I was able to knock out enough plastic to allow the IDE cable to sit comfortably against the bottom of the case without raising the motherboard any higher. The power supply was another issue – I scavenged a small 120 Watt ATX power supply from an old PC tower and carefully stripped it of its protective metal housing. With the small height gain, the power supply just barely fit inside the case and pressed snug against the imac logic board, holding everything in place. It wasn’t perfect, but it would do.

imac lc iii vga hole

imac lc iii vga board

A final problem I ran into was that the connector on the back of the slot-loading DVD-ROM was on the opposite side of most laptop drives, meaning that my IDE adapter board would stick way too far outside the case. This problem had me stumped for a long while, but I eventually came up with a hack to make it work. I cut a hole in the bottom of the DVD-ROM and moved the main controller board under the drive, and ran the ribbon cable to it. This way, I could turn the board 45 degrees and make use of the IDE adapter, although at an awkward angle. Doing this modification also required that I re-run some motor control and switch wires on the drive.

imac lc iii front open

imac lc iii back

Finally, with all the major modifications complete, I carefully fitted all the components into the case, ran power and data wires to the drives, and attached the audio and video cables. While all my hacks had worked throguhout the process, I still half-expected the whole mess to go up in smoke when I powered it up. Yet, when I flipped the switch, the machine slowly came alive. With some final modifications to add a small processor fan and proper AC connector, my iMac LC III is now happily running Mac OS X 10.3.9.

imac lc iii iwork

Mail Stamps

June 17, 2005

I’ve been meaning to add this little app for a long while. Mail Stamps removes the new aqua buttons from Mail in Tiger. While I know many people who like with the new look and enjoy the segmented toolbar items, I – and apparently others – happen to prefer the Panther look. Mail Stamps runs and changes the .tiff files inside Mail back to the Panther look. It has an uninstaller, but as always, make a backup of before running Mail Stamps. Mail now sports the good old buttons I’ve come to know and love in past OS releases.

Magstripe Snooping

June 16, 2005

Here’s a little mid-week hardware hack: building a magstripe card reader (a.k.a. credit card reader). When completed, the device can pull data off just about any type of common magstripe card, including credit cards and identification tags.

Last summer I took a trip to Ohio and made it a point to visit a gigantic store in Dayton – Mendelson’s Liquidation Outlet. They carry just about everything you could want, however I was particularly interested in the several floors of electronics surplus items. I happened across a magstripe reader with a connector attached, but it was unwrapped with no documentation. It’s surplus, so you take what you can get. On the off-chance it might be useful for a project such as this, I paid about $10 for it. It’s been kicking around since then, and only recently have I done something with it.

I looked up the documentation for the reader I had using a model number found on the bottom, and discovered it was an Omron 3S4YR-HSR4. It could read common cards and output TTL signals, so I searched around some more to see what could be done with it. I found a SourceForge project dedicated to magstripe readers, called Stripe Snoop. They provide diagrams showing how to connect the reader to a PC game port, so I took a trip to my local RadioShack for a matching connector. With a little soldering, I had the finished magstripe reader ready to go.

The Strip Snoop project also maintains an open source program for reading and parsing the card data that is sent in from the reader unit. With my aging Windows box fired up (ugh), I swiped nearly every magstrip card I could find to see what they contained. For example, I was surprised to find that my college student ID contained only my social security number as an identifier.

In short, building a simple magstripe reader isn’t too hard a task, and it’s interesting to see what information is hiding from you even when it’s right in the palm of your hand. While the reader I built only connects to a PC game port, the signals are standard TTL level, so building a USB version is quite feasible. With complete software and diagrams available from the Stripe Snoop project, it’s trivial to get a basic reader up and running on affordable hardware. Total project cost was about $12 plus a few minutes of soldering.

Update: Via Bruce Schneier: Ownership of Mag Stripe Readers May be Illegal in Illinois. Crazy.