DIY ECG Electrocardiograph kit
Not bad for $44 – lots of project to make with this – “We have found many different uses for this little kit! Applications ranging from the traditional ECG/EKG monitor to the ‘Newly-Wed’ Love Synchronizer! One of the main reasons we designed the ECG1 was to answer a long running debate here at the shop. We wired up the ‘Boss’ and finally confirmed he does not have a heart! Use the ECG1 to astound your physician with your knowledge of ECG/EKG systems. Enjoy learning about the inner workings of the heart while at the same time covering the stage-by-stage electronic circuit theory used in the kit to monitor it.” Link.
Excellent guide on replacing capacitors in old radios “Second only to power cords, capacitors are the most failure-prone components in old radios. In a professional overhaul, it is common to replace all of a radio’s large electrolytic capacitors and small paper capacitors. This article explains how to do just that. In many cases, this “recapping” is all that the radio needs to be restored to health.” 
Here’s the first test of a 3D RSS reader “idea” I’m working on – I shot this last week before I left for Macworld so it doesn’t really show what’s possible, or how it works now, but I think it’s easy to get the idea – in the current version you point it toward a real geographic location and using a “lens” (a tablet pc with x,y,z axis tracking) as you point it at something you get the feeds, so let’s say you point it towards Redmond, WA you’d get news about Microsoft or something. For now I need to manually let it know where it is, but I think there’s a way to feed in more real world data. Ok, here’s the video – 
Paul from Dotmatrixsynth makes musical instruments out of printers, here writes – “I’ve got an ongoing project, reprogramming the firmware in these 1985 Epson LQ-500 printers to turn them into musical instruments. I originally just wanted to make a sort of homemade mellotron, but it’s evolved into a much deeper project. These printers (like all printers) have a computer inside that operates all the motors and handles the parallel port, etc. The software that drives that computer is all on an EPROM (a reprogrammable ROM chip.) I remove the EPROM, erase it, and reprogram it with my own software that I’ve developed by reverse engineering the printer and its computer.” 
Tomi writes – “This is a simple microphone preamplifier circuit which you can use between your microphone and stereo amplifier. This circuit amplifier microphone suitable for use with normal home stereo amplifier line/CD/aux/tape inputs. This microphone preamplifier can take both dynamic and electret microphone inputs (preamplifier provides power foe electret microphone elements). The idea of this circuit is to keep the design as simple as possible to be easy to build. That was my goal when I needed a simple external microphone preamplifier for my mixer. The performance of the circuit is nothing superior but can be used with many not so serious projects.” 
Nice use of a mint tin! – “This site features projects and circuits for building stereo microphones from low-cost Panasonic electret microphone capsules. Included are Mid-Side, XY, and Blumlein microphone setups. In addition, there are interesting related circuits and links to sites with microphone information and parts sources.” 
The Goldfish Online has some really interesting LEGO logic gates – “…designed working NOT, OR, NOR, AND, and NAND gates. Using two NAND gates I have produced a NAND gate latch or Flip-FLop. The natural follow on from these is clocked logic, full-adders and ultimately a genuine “computer” device. At the moment all these gates essentially just demonstrators. They work, but because of the limitations that arise through gear slippage, the real practicable use is probably not that great.” The details of logic gates can be found here –