Glowing LED Desk Alerts you of Emails, IMs

KEA desks are DIY-er favorites. Take this IKEA Gallant desk for instance. The desk comes with a frosted class top, and where there’s frosted glass, cool LED effects are not far behind.  The desk monitors HTTP requests and illuminates LEDs when a new chat or email message arrives.

Each light is individually addressable so plenty of illuminated patterns are possible.8 LED modules are connected via a USB controller to the desktop. 

 A node.js web server listens for incoming HTTP requests and connects to Growl ( a program which manages social  notifications).  The instructions detail the process of implementing the various hardware and software components of this project.[Link]

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USB Peripheral to Google’s Nexus One Android Phone

A Nexus One Android phone normally won’t let you run any other peripheral device. But if you hack the phone to run on “USB Host mode” you can plug in all sorts of USB peripherals. USB Host mode lets you to external hard drives, digital cameras, external monitors, etc. to your Android phone just like a regular computer!

The Android hack shows how to enable USB Host mode by tinkering the Android firmware.With the USB Host mode enabled, a Nexus one can be used like a standalone workstation. As the video above shows, you can play movies, start a webcam, connect a keyboard, and even a large monitor display. If you give it a try, let us know how it goes in the comments. [Link]

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How to Power Your USB Gadgets with Bike

With more and more gadgets coming out every day that utilize USB for charging, it’s almost necessary to have a USB port available at all times.  This DIYer decided to create a 5V generator using his bike and a modified USB car charger. The 5V USB plugs are situated under his seat and he has a carrying rack for cellphones, GPS, or MP3 players on the go.

The USB bike generator works by placing a rotating wheel perpendicular to the rear wheel of the bike with a heavy spring. The mini-wheel turns a stepper motor to generate a charge that is then smoothed out by an in-line rectifier.[Link]

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Solar Powered Lithium Ion Battery Charger

The circuit below feeds a controlled current and voltage to a 3.6v lithium ion battery. The current is limited to 300ma and the voltage is limited to 4.2 volts. The circuit uses a LTC1734 IC from Linear Technology. No diode is needed between the circuit and a 6 volt solar panel. Some very nice 6 volt solar panels are available from www.plastecs.com Their SP6-200-12 cranks out about 1 watt while the SP6-300-12 can produce about 2 watts. Assuming a 6 hour sunlit day, the 2 watt panel will pump about 1.8 amp-hours into a battery.

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TDA2030A Amplifier used in Home Theaters

TDA2030A is a well used class AB audio amplifier IC. This one is mostly used in nowadays home theater systems for it’s some good features,

1. Small size IC(package PENTAWATT V, almost size of regular TO220)
2. Maximum voltage range (upto 44Volts Vs MAx)
3. Very low harmonic and cross-over distortion.
4. Suited for more reliable applications without regulated supply
5. Up to 35Watts RMS driver output
6. Thermal shutdown protection

This IC require less external components too, making it easier for a beginner to make this on veroboard. The original circuit I got from it’s datasheet. A little modified circuit below,

This can be operated with single supply line, but that topology gives less output power, hence this bi-voltage topology is used everywhere. We need to provide +/- 12V to it. We can easily get +12V and -12V from a 12-0-12 CT step down transformer. And, as this IC doesn’t require regulated supply, we can feed voltage directly from rectifier with just a capacitor.
Well, the IC costs around 25 rupees, and together with all other materials as PCB, other parts the cost of final board doesn’t exceed 70-75 rupees.
                                                                                                                  Source:circuitsprojects.net

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Touch Sensitive Light Dimmer

With IC SLB0586A from Siemens you can build a simple touch light dimmer circuit that will allow you to adjust the lamp intensity. Together with a TIC206D triac, it enables smooth regulation of light intensity from a bulb of 10W – 400W. A coil of 100µH/5A is required to suppress switching noise.The voltage supply is obtained through R2, C2, D1 and C3 and is about 5.3V below the network potential. The touch sensor that is used to drive the IC is connected at pin 5 through two 4.7M? resistors, R5 and R6, in order to ensure user security.
In the adjustable touch lamp schematic we can see three selection connection , for selecting one of three modes of the IC. When the B connection is used, the light will always be ON at the last level that we used. With A or C connection the light will be ON at the minimum intensity. With B or C, the purpose of regulation is reversed with each use.
Schematic of the adjustable light with touch sensor

When the sensor is touched for a short period of time (50 – 400 ms), the lamp will be ON or OFF. If the sensor is touched for a longer period of time it will start the regulation process. Warning! This touch light dimmer circuit has some points where lethal 220V is present, please do not try this project if you are not qualified.

Source: electroschematics.com

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