Here’s a Halloween prop leftover; [Chris] built his own version of singing heads from Disney’s Haunted Mansion on his porch for last year’s ghoulish decor. A projected image of actors singing a spooky song gives each of the four Styrofoam mannequin noggins its own digital life. There’s an optical sensor on the porch stairs that is tripped by unsuspecting candy-seekers. An Arduino monitors the sensor and uses AutoHotkey to start the video clip on a netbook. Check out the video after the break to see the finished display do its thing after dark.
[Brian] came up with an interesting PC cooling setup. He lives up north where it’s chilly in the winter. Using a bit of dryer ductwork and he was able to harness the outside air to cool his box. The system uses a window insert along with a dryer hood to suck in the outside air with a PC fan. We hope the air is adequately warmed, as it is exhausted into the room. Join us after the break for more pictures of his setup.
Did you know that a standard camera flash is much too slow to capture high quality images of bullets? A relatively long flash duration results in blurred images of the bullet. By building this air gap flash a bullet can be frozen in mid-air, producing some stunning results. There is an element of danger here, and not from the bullet. This flash uses a 35,000 volt capacitor to produce the mini-bolt of lightning which serves as the light source. The unit can be built for a few hundred dollars, which sounds like a heck of a deal if commercial models really do start at $8k and go up from there.
Now that the photographer has a super-fast flash, a camera axe takes care of the timing… which is everything.
Bust out that 555 timer and use it to build your own AM radio transmitter. The circuit that [Rtty21] is using only needs the timer chip, an NPN transistor, three caps, three resistors, and a potentiometer. It generates an amplitude modulation signal around the 600 kHz range which you will be able to pick up with any normal AM radio. From the comments on the article it seems you’ll get around 30-40 feet of range out of the device. We don’t see this as a competitor for the FM spy microphone, but maybe you can use it as a diy baby monitor.
We’re not sure where the fascination to have your libations flung at you came from, but we can’t say we’re entirely against it. This beer catapult robot (dead link try Internet Archive) will pull a cold one from its gullet and fling it to you, or in your general direction. While he doesn’t have the source code available for the Arduino bit, we’re OK with that. We’re more interested in the mechanisms at work here and there are plenty of pictures of his set up. It seems very similar in design to this one we covered back in 2007, which also appeared on” The Late Show with David Letterman”. Join us after the break to see the thing in action.