The Bt878 chipset is fairly common on TV tuner cards. The chip has a built in analog to digital converter with a sample rate of 119kHz to 448kHz, well above the standard audio rate of 44kHz. The hardware has to be hacked a little to inject your signal since the chip is usually receiving audio from the turner. With some driver hacking this chip can be pushed to 896000 samples per second. Recent developments make things even easier with ALSA support.
[thanks rockarolla]
Max and Phildog hit the shooting range this weekend to see if they could accurately measure bullet speed using Audacity. Using Audacity to examine the wave form they can determine the time between the shot being fired and striking the target. This time needs to be adjusted based on the known distance to the target. They’ve got data from quite a few different guns, but this is just a test run and they’re still improving their technique.
Welcome back to A-DJ-Hack-Every-Other-Day. Maintaining clean vinyl will improve the sound quality and lifetime of your records and cartridges. It’s also a great first step when ripping the audio. This record cleaning system is built from the platter of an old turntable and a canister vacuum. The record clamp is constructed from MDF and is used to rotate the record and protect the label. The vacuum hose has a modified crevice attachment used for removing the excess cleaning fluid. The site includes a recipe for making your own cleaning fluid. Of course any money you save on this project will probably be spent on more vinyl.
This coil launcher is based on a disposable camera flash system. It uses the charging system from one camera plus the the flash capacitors from four cameras. The coil is 200 turns in 10 layers wrapped around a glass tube with a 3mm inside diameter. The projectile is a 2.5mm diameter nail. It certainly isn’t as high powered as some of the systems we’ve featured, but firing at 20-25m/s it can still be dangerous.
[thanks phuzzy3d]
Timothy Wisdom’s D’Groove is a digital haptic force feedback turntable. D’Groove takes digital music control further than products like FinalScratch. The platter has four divisions marked on it; each line represents one beat in a measure. Every time the record makes a full rotation it plays a full measure. The force feedback allows you to actually feel where the beats are.
The Q-Slider represents where in the song you are. As the song progresses, the slider moves to match. If you grab the handle it’s like picking up the record needle. Sliding the handle you can feel the intensity of the track. There are a lot of other features and possibilities that I haven’t covered. Check out the video on the site to see it in action.
Automatic Position Reporting System (APRS) is used to transmit location and other real-time data over amateur radio frequencies. [Scott Miller]’s OpenTracker project is designed to encode the NMEA data from a serial GPS receiver for transmission. It doesn’t have to be used for GPS telemetry though, you could hook up a weather station or any other remotely located project. Scott has boards, parts and even full kits available.
The transform switch on a mixer is used to turn ON and OFF individual channels. The toggle switches used in the DJM-707 are three position switches, but their plastic caps limit them to only two positions. [Sp4rk] removed the switches from the unit, wired the other off position, and trimmed the cap. After this modification the switches have an OFF-ON-OFF motion. Here’s an MP3 of Sp4rk scratching with the new modification and a Coral cache of the transform modification.
