Turn-key PCB assembly services in prototype quantities or low-volume to mid-volume production runs

Expanding Attiny microcontroller with shift register

Attiny microcontrollers have small footprint leading to smaller number of I/Os available. These microcontrollers are meant to control simple things like reading sensors, driving relays and so on. If you come to the point where you need more I/O pins then there are two options – use bigger microcontroller or expand number of pins with port expanders or with simple shift registers. For smaller microcontrollers port expanders may be too costly solution, because of limited memory it may require to much of driving like I2C or SPI expanders. In this case better solution is to use shift registers that can be driven pretty easily with not much overhead code and you can get as many pins as you want by connecting them in cascades. silentbogo wrote a simple instructable on… Continue reading

Eye catching LED ring display

There is always a dilemma on how to build an indicator for your next project. There are many options like LCDs, LEDs, VFD. Sometimes one or another is enough, but eventually you want something eye catching and obvious that could be seen from distance. For instance for water meter a dial based display probably is better than LCD. IT can be seen from distance and is informative to tell how mutch water is in tank. John simply built a LED ring display out of 16 single color LEDs. He needed to use shift register, but he thought that popular 74xx595 chip is very current limited. Total current draw shouldn’t exceed 50mA which is like 2 more powerful LEDs at a time. So he looked for more proper shift register and… Continue reading

Interfacing shift register with AVR

74HC595 shift register

The shift register is one of the vital things to learn while designing an embedded system. Using shift registers, one can increase the number of input as well as output pins available in any microcontroller. There are situations where you want to interface many peripherals together and also keep the low system cost as well as reliable. This is where the shift register come into the picture. For example, in a joystick used to play games, instead of running all the pins from the console to the joystick buttons, using a shift register reduces the number of pins almost by half.  This not only increases the reliability of the joystick but also has helped in saving a lot of money in the long run. Another advantage of using shift register… Continue reading

The Colorful Ceiling Fan LED Display – A Huge Sparkling Star in the Dark!

Everyone must be very familiar with this nursery rhyme, no matter what ages you are… “Twinkle, twinkle little star, how I wonder what you are! Up above the world so high, like a diamond in the sky!”… Well, even though you cannot reach the stars in the sky, but you can always built something similar with it, such as this Colorful Ceiling Fan LED Display, which is in a star shape! If you look on the above picture, you’ll see a huge red color star in the middle of it. Actually, it’s the effect of POV (Persistence of Vision). Yep, with the help of POV technology, you can easily create a ceiling fan led display! Before you hop into project, you have to make sure that you’re using performing the… Continue reading