Headphone Tube Preamp Kit

May 3, 2010 by Mike Szczys 23 Comments

If you’re curious about tube amps but don’t have a firm enough knowledge base to dive right in you might want to try a kit. [Mark Houston] reviewed one such kit and we enjoyed reading about his experiences. It comes with everything you need save soldering tools, an enclosure, and the final connectors ([Mark] used RCA connectors). There is a full schematic available and the assembly instructions take you through tube matching and using that piece of copper coil you see in the picture to wind your own inductor. Consider trying this primer before you jump into building a single tube, multiple tube, or an amplifier of your own design.

[Thanks Gio]

A More Powerful Boost Charger

May 2, 2010 by Mike Szczys 28 Comments

[Meseta] built a powerful boost charger to top off his portable devices. He was inspired by the Minty Boost but wanted to overcome the rather limited capacity provided by the two-celled product. He ended up building his own DC to DC boost circuit rather than using an all-in-one IC. As you can see, the result uses four 18650 lithium-ion cells, normally found in laptop batteries, and can power two USB devices at the same time.

DIY Pulse Oximeter

May 2, 2010 by Mike Szczys 28 Comments

This pulse oximeter turned out very nicely. It is based around a Freescale microcontroller and detects pulse as well as oxygen saturation in your blood. The sensor is made of two wood pieces and allows two wavelengths of light to be shined through your finger. A sensor picks up the light on the other side of your stubby digit and the readings are compared to calculate saturation. Check out the finished project after the break.

We saw an Arduino-based oximeter a few months ago. These kind biometric hacks are rare around here. If you’ve got a well documented project don’t forget to tell us about it.

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Motion Sensing Light Module

May 2, 2010 by Mike Szczys 5 Comments

[Muris] is pumping out the home lighting hacks. He developed this motion sensing module as an add-on to the IR switch we saw last week. There’s some kind of fuse box above his entry door and its white cover, which you see above, is where he mounted an IR distance sensor to detect movement and switch on the lights. The RC5 infrared protocol is used to transmit the necessary signal to turn the lights on, then when a set amount of time has passed it will turn them back off again.

Phasor A/V PAL Demo Uses ATmega88

May 1, 2010 by Mike Szczys 51 Comments

[youtube=http://www.youtube.com/watch?v=sCN1bqRG-7o]

Above is a new demo video called Phasor developed by [Lft]. It is run from an AVR ATmega88 and a few passive components, and the result is pretty amazing. [Lft] goes into detail about the tricks he used to get this up and running. The chip is clocked at 17.73447 MHz which is exactly four times the frequency of the PAL color carrier wave which allows him to fake a smooth signal. He also uses a timer trick to get the voltages that he needs. The work done here is beyond hardcore and quite frankly we can’t believe he managed to fit all of this into 8.5 KB of program space with just 1 KB or RAM. We wonder if there’s enough room there to add sound and color to the AVR Tetris project.

[Thanks Sprite_tm]

DPAC Put Your Alarm Clock To Shame

May 1, 2010 by Mike Szczys 16 Comments

DPAC, the Dynamically Programmable Alarm Clock, goes far beyond what you would expect an alarm clock to do, yet we find all of its features useful. You can see there are four buttons at the bottom that control the menu scrolling. The second from the left currently reads “Sync”, a feature that the clock uses every 10 minutes but can be forced manually. This will check your Google Calendar, schedule an alarm for the next event while factoring in driving distance, traffic, and weather conditions. It’s got an audio system for radio and iPod operation, but also includes some home automation options. Using the X10 communication protocol it can turn on lights, start the coffee maker, and open the blinds as part of a gentle wake-up cycle. All of this is configurable through the clock itself, or via the web interface. The prototyping was done on an Arduino but the final version uses an AVR ATmega324 along with a Roving Networks RN-134 WiFi module (datasheet) for connectivity. Check out the demonstration video that [Eric Gaertner] and his fellow developers filmed after the break.

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CPU As A Heat Sink

May 1, 2010 by Mike Szczys 51 Comments

We’ve noticed that wireless routers pump out a bunch of heat. [Jernej Kranjec] wanted to make sure that he didn’t fry it once he started adding more load to his router using OpenWRT. What he came up with is the idea of using an old CPU as a passive heat sink. He applied a bit of thermal paste to the center and some super glue to the corners. You can see the finished product is an old AMD chip adhered “dead bug” style to the stock processor. We’d bet it’s not very efficient compared to an aluminum or copper heat sink, but it normally would have no help in shedding those extra degrees.