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Add USB LED Notifications To Your PC With Just a Bit of Soldering (Video)
Arvydas Juskevicius (say that five times fast) is an independent software developer and hardware hacker based in London (which is where I got a chance to talk with him) who's decided to bring the useful LED signalling capabilities of many modern smartphones into the world of desktop or laptop computers. With his £10 BlinkStick kit (£15 pre-assembled), you get a programmable multi-color LED that's about the size of a flash memory key. Deceptively simple -- it's essentially one giant pixel, after all, which might not sound exciting when you have millions of them on a dense display surface. But that LED light is something you can use as a signal for alarms, or to tell you that you have a message from one app while another is at full-screen, or practically anything else that you can devise software to notice and react to. I get the sense that Juskevicius would prefer that people get the kit version, to help spur interest in actually soldering some hardware rather than just plugging it in. If you're allergic to paying in other than U.S. dollars, the BlinkStick is also available from Adafruit Industries. Watch the video below to see it in action.
I was thinking pretty much the same. This is a computer controlled, USB RGB LED (triplet of TLAs!). You can get a Tiva Launchpad from TI preassembled with RGB LED (surprisingly bright BTW) for $13 including shipping. The 15 GBP is about $25 and 10 GBP is $16 in comparison-- I don't know if shipping included in price. Granted the Blinkstick is in a smaller form factor that plugs in directly but the Launchpad has a ARM Cortex processor, GPIO, ADC, UART, USB, etc on it which you can use for other things should you tire of the notification light thing.
... which is something like http://www.ck3.co.uk/minimus-32-avr-atmel-atmega32u2-usb-dev-board.html, which does USB in hardware, has 2 LEDs already on board and only costs £6.00, or as little as £3.50 if you buy in bulk. Plus you can emulate pretty much any USB device you want - I've used one to drive a whole set of RGB LEDs by mimicking a MIDI output device and mapping notes to colours.
£15 quid for a single LED driven by an inappropriate microcontroller? About the dumbest thing I've heard in a while.
Modern connection interfaces are complex enough that you need an IC to negotiate a connection before you can even get a LED blinking. Today's systems aren't exactly designed for hobbyists to build things.
Get an old beige box. You can solder a resistor and LED to the DTR pin of a serial port, and program it with a couple lines of assembly -- Oop, nope. The modern OSs aren't really designed for hobbyists to build things either. You'll be learning how to write a kernel driver for your OS if you use Linux. This is why I still use and make small DOS-esque OSs -- It's quite easy using BIOS interrupts. Also, you can still install DOS on nearly all x86-64 systems...
Data Terminal Ready is just one pin, but with it and the RxD / TxD pins you can build a simple lock-step electronic coms project on a serial port -- So you don't have to implement the whole RS232 chipset just to do a little manual IO. Parallel ports have many more such pins to play with, and don't require serialization either. That's why I teach kids to make robotics with DOS like OSs on my spare "junk" -- Because it's so much faster, cheaper, and easier than with USB, or even RS232 serializing and deserializing state -- Save that for when they get a bit more skilled. There's something almost magical to watching bits flip in memory by making and breaking electrical contacts; Folks immediately start thinking up ways to use such a thing. It's fun watching the scales fall from their eyes as kids realize computers aren't impenetrable black boxes full of voodoo. It's kind of funny that you have to buy a kit with ICs to make more transparent the interface provided by making and breaking pins on older hardware.
In my experience, once you get past a couple of LEDs or controlling higher voltage switches via contactors, etc. the next stop usually isn't a notification app for your system -- It's a breadboard full of gizmos, or using your PC to control your other gadgets.
Eg: Readers who liked TFA also liked LIRC.
(swap the LED with IR-LED, and control your home theater setup)