For his A-level electronic course work, [Andrew] decided to build a digital sound recorder that doesn’t use a microcontroller.

[Andrew]‘s build captures audio from an on board microphone at 8000 samples/second. The audio is digitized into 8-bit sound data and sent to an SRAM. The recording and playback functions are controlled entirely by 4000-series logic chips. He admits the sound quality is pretty poor; this is mostly due to the 8kHz sample rate. In some circles, though, a terrible sample rate is seen as being pretty cool so we’re not going to say [Andrew]‘s build is useless.

There’s some pretty smart design choices in [Andrew]‘s build, like a cut off filter on the microphone set at 4000 Hz (the Nyquist frequency of his system).  For the recording medium, he used an SRAM that can hold about half a megabyte of data. At 8000 samples/second,  [Andrew]‘s build can store a little more than 60 seconds of audio. The build may not be a logic chip computer, but there’s not any question in our mind that [Andrew] learned something. Check out [Andrew]‘s 66-page coursework report here (PDF warning).

[Darkrom] has set a new standard for Hack-A-Day readers… I haven’t seen it in person, but that looks like a legit Hack-A-Day tattoo.

[null] sent in a new use for a frequency generator, a spare car amp, a sub-woofer and a plastic coffee can – brass cartridge polishing.

[LoopyMind] sent in this Game Boy Advanced Movie Player IDE hack. It’s pretty much a direct CF to laptop drive cable with an external battery supply.

[Dingolishious] sent in a POE UPS/remote power control solution. Could be handy if you’re using many POE devices, or if you’re having power issues. He added an inexpensive remote power monitor/switch solution behind his UPS. It senses power outages and kicks out an email – and allows remote power cycling of his POE devices. Of course, if you’ve got a linux box behind the UPS, it can monitor the output from the UPS and send notifications.

[William] added a preamp stage to his iKEY usb recorder. looks like an interesting toy – it’ll record audio directly to a USB flash key. The pre-amp allows him to record in more challenging environments.

[Andrew] noted a simple mod to increase the deadly fire power of the ubiquitous airsoft pellet gun. It’s just a matter of reducing some extra space in the spring compression area.

Last but not least, [VIPER] modded his projector to use a 12v halogen headlight bulb. Not a bad idea – at one point I was pondering a 550 watt source four halogen as a possible replacement.