The circuit consists of two parts, a constant current generator using a PNP power transistor (Q2), and a peak-detecting shutoff circuit using a high-gain opamp (IC1). To start the charge cycle, switch SW1 is momentarily closed, causing C1 to discharge. As IC1′s inverting input is now higher than its non-inverting input, its output goes low, [...]

Tired of switching having to manually switch between his headphones and computer speakers, Peter Lavelle decided to go all out and built a LAN-controlled audio switch to solve the problem. Source: solderintheveins

Ever feel like you’re missing some beats? Does your day need a better soundtrack? Feel the boom with the Super GrooveAxe! It’s a pocket sized, battery powered drum machine & sequencer that you can take anywhere. Source: nmcclana

The Garage Parking Assistant makes it easy to pull in the garage by signaling you with a traffic-light style display of when to pull in (GREEN), slow down (YELLOW) and stop (RED). If you pull too far in the Red LED blinks to let you know. Although this type of project has been done before [...]

These LEDs are magic, inside the ordinary looking LED dome there is actually 3 LEDs along with a tiny controller that sequences the lights in some cool patterns. Stay tuned for a peek inside one of these LEDs! It first cycles the individual colors quite rapidly, and that is followed by some slow color fades [...]

The star is about 35cm across and designed to be displayed indoors in a window. I originally created the star three years ago using a 16F872 controller. The original version worked ok – but had no spare memory for adding more features. This new version uses a 18F2620 because I now prefer the 18F series [...]

Miniature usb capslocker, this is exactly the same as original project, i have made even smaller board. Dimensions are: 2.5mm x 11mm x 12mm, used pcb can not be thicker than 0.75mm, else it wont fit into USB. Source:diy.elektroda.eu/

Electronic business card / scroll display. 85 SMD 0805 led’s matrix display, Atmega88V uController, and couple of other smd parts. Dimensions are 24mm x 85mm, supplied from 3V small coin battery. It will work for long time, even on discharged battery (2V). After button is pressed, device is waking-up from power-down mode and start scrolling [...]

Having made some of these earlier, I decided to add a few more for the Christmas season.  These light boxes, or signs are easy to make, very low cost (the only thing I have to buy is the lights).  Lights used are mini-incandescent lamps that are low watt, low heat regular Christmas lights. Source: Creativeman

I have a DVD player, a VHS video, and a mini-DV video camera. I record off the mini-DV to my PC, I’m also recording VHS to digital in a similar way. Sometimes I take audio-video from the DVD to the PC. I used to feed composite-video to my PC’s graphics-card, and the audio to Line-in [...]

When doing more than one thing at the same time it is very easy to lose track of time. Exposing PCBs to UV light is delicate work and overexposing will result in, well, you know what.  Housing for the exposure system shouldn’t be a problem because those old broken PC scanners come very cheap. Device [...]