I would like to wish my readers a Happy New Year and may all your wishes come true. As you may have experienced, during the holidays, hobbyists get some free time and they like spending it building stuff. In this case the author, Infernoz, build this 8 LED POV display, which seems like a fun way of wishing a happy new year. The device is based on the Attiny26 from ATMEL and from the video we can see it works quite nice, but unfortunately I was unable to locate any source code posted on the project page, but this is not that bad as you can find POV source code from others projects(POV1POV2POV3) if you’re interested in building one.
You want to learn more about DC to DC boost converters? Here is a good and practical application of such converters, an LED tail light for your bicycle. Why do you need a boost converter for that you might ask, when you can simply have a battery power up some LEDs. Well, this way you greatly increase efficiency, you increase the number of LEDs you can drive and thus increase the perceived power of light. And yes, you will learn about them.
This project makes use of the National Semiconductor LM3410 chip. This chip provides a current regulation rather than a voltage regulation and makes it suitable when working with LEDs. This current regulation is done by switching a NMOS gate at constant frequency of 525Khz ( you can also chose 1.6Mhz) and varying the duty cycle, the so called pulse width modulation. Given a constant frequency varying the pulse width results in varying the mean value in time. The regulation is done by providing a feedback current that causes a voltage drop on a resistor which in turn is fed into a comparator.
The output of this comparator goes to the PWM comparator where it faces the output of the amplifier that reads the switched current through an inductor. The result will be a PWM signal attacking the NMOS gate and thus providing a steady mean output current value. The current sensing amplifier also provides an output for switched current limiting. Some nice features of LM3410 makes things easier, it’s internally compensated, has a very low stand-by current, has dimming possibilities and thermal shutdown.
As the author states in his article you have to be careful when choosing components. Since the operation frequency is pretty high the diodes through which the inductor discharges must be high speed or you risk blowing the chip. Taking things a step forward he added a PIC12F683 microcontroller to provide some light effects selected by a pressing a button.
If we look closer at this project we can see it can be further developed, using the dimming possibility of LM3410 you can also turn it into a stop light. Whenever you break light intensity goes higher. Another development is to adapt it to be used with a dynamo. Have fun.
A persistence of vision (POV) display is a device that creates an apparently still image using rotating LEDs with great speed. The human eye is not able to distinguish every image individually, so the picture formed appears as a solid image. The POV phenomenon is not a new discovery and a lot of POV display projects have been made. However, this one right here has two different attributes that differentiate it from other POV displays: it is located on a fan placed on a ceiling and it’s silent.
This project uses a fan with 5 propeller blades and every blade has 32 LEDs mounted on it (that means a total of 160). These LEDs are connected to an Atmel microcontroller on an Arduino board. The POV display also uses 74HC595 8-bit serial-in, parallel-out shift registers that convert serial-in data into parallel-out data. The microcontroller generates the sequence in which the LEDs are lit, thus creating the image.
The location of the display makes it pretty cool and the fact that it’s attached to this kind of fan makes the whole device completely silent, which is quite different from most POV displays out there that are rather noisy. Having a thing like this blinking in your living room might seem like a good idea if you want to impress a guest audience, but other than that I can’t find a reason for actually using it.
Have you ever found yourself in a situation where you wanted to talk about something important or just simply wanted some peace and quiet while enjoying your drink and a damn TV wouldn’t shut up? Chances are you have. But from now on, you can use this little gadget to silence those TV sets that bother you with loud, uninteresting stuff. You can carry it in your pocket and you can surely have a laugh using it.
Humorously named TV-B-Gone, this TV Disabler can make some annoying situations quite entertaining. The TV-B-Gone can turn off most of the TV sets available, while having about the same size as a universal remote control. It is a nifty little kit made by Adafruit and it is available for purchase for $19.50. It possesses an Atmel ATTINY85V-10-PU programmed microcontroller, 4 IR LEDs used as emitters and a double AAA battery holder (you can find a complete parts list in the link).
The TV Disabler must be pointed at the TV you wish to quiet down. It has a single button that must be pressed and then it starts to transmit its signal using codes that are stored in its memory for all major TV brands. It takes about 2 minutes to send all the codes, but most TV sets will turn off. The TV Disabler also has a green LED that starts glowing once the device is transmitting.
Since the original kit from Adafruit doesn’t have a case, you can make one like the one in the picture above. This project uses a modified Miniature General Purpose ABS Box 1551 Series from Maplin Electronics Ltd. You will have to make 2 holes, one for the button, and the other for the LED. Putting it all inside the box may be tricky, but once you get it right you will have the TV-B-Gone ready and waiting. And you can say goodbye to those noisy TVs disturbing you.
don’t forget to check youritronics custom version of tv-b-gone.
