Cascade-able RGB light effects

This is a simple project which creates RGB light effects driven by microcontroller. It uses a custom built RGB LED strip that can be cascaded in to long lines. LEDs are controlled in groups where different color belongs to different group. Light patterns are controlled by PIC16F72 microcontroller which drives LEDs through ULN2003A driver chip. Driver chip is capable of sinking 500mA of current, so this parameter should be kept in mind when attaching multiple LED stripes in to long lines. Continue reading

Electronic LED dice with tilt sensor

There are many electronic LED dice projects around where you can choose the layout, triggering and circuit. This one has something a bit different from other. First of all PCB is round and LEDs are numbered instead of positioned to mimic physical dice. LEDs here are positioned in circular pattern that labeled from 1 to 6. When dice is rolled, LEDs display chasing effect and gradually slows down until it stops at one of LEDs. Dice is built around PIC12LF1822 microcontroller. LEDs are connected by using three wires (Charlieplexing). Dice can be triggered with tilt sensor by shaking the dice. It is powered with coin cell battery. There is a switch to turn on and off. If dice is left powered for long time, it automatically enters sleep mode to… Continue reading

Low cost home made plotter project

Probably many of you are thinking about how cool is to have CNC plotter or 3D printer. There kits and ready printers available for reasonable price. But still they are pricy for hobby use. But nothing is lost you like to build stuff. posted his progress in building plotter where he wanted things to be cheap and simple. He’s build all part separately by finding simplest and cheapest solution to rising problems. Some of his parts came from Epson printer. He also purchased used stepper motors from local junk store. The electronics part he built around PIC16F877 microcontroller. He built his own motor driver circuit out of discrete components, but it seems that results aren’t as good as it would be with specialized chips like Allegro A3984. Connection to… Continue reading

Microcontroller driven resistor decade box

Usually resistor decade boxes are mechanical – a rotary switch comutates resistors while turning it around. But if you decide to build one, you may face problem by selecting this switch. They seems to be quite expensive and quite old fashioned. Stynus has been planing to build one of those, but mechanical switching handle didn’t look very attractive, so he decided to switch resistors electronically through microcontroller. He ended up by building three PCBs where one is a control board carrying LCD, PIC 16F648A microcontroller, rotary encoder and push button. Other two boards are resistor boards – one for high value resistors and another for low value. Each resistor board caries 16 small relays that are controlled through shift registers. Then only annoying thing with electronically controlled resistor box is… Continue reading

Handy count down timer with bright display

There are many uses of countdown timer. It can be used for PCB development, in a kitchen or during workout. All you need that timer was easy to set up and start. Umetronics have build simple PIC16F886 based countdown timer with four bright 7-segment displays. LED displays are driven using TLC5916 LED driver and couple dual P-channel MOSFETs. Time can be selected with rotary encoder which comes with button for select. When timer runs out there are two options for notifying – one is display flashing and another micro-switch selectable sound option along with green LED indicator. Sometimes sound might be annoying, so you can always turn it off. Timer is two AAA battery powered. So it is small portable timer for any use. Continue reading

Binary digital wristwatch for real nerds

It is said: “There are 10 types of people in this world, those who understand binary and those who don’t”. If you choose understanding side, then you might want to wear binary wristwatch. Building such watch is fairly simple and easy, because you only need few components and even simpler code. Elias watch is based on PIC microcontroller which comes in SSOP-20 package. With few difficulties on soldering it to small PCB he had it running. Watch is powered from coin cell battery CR2032. With smart software solution combined with sleep modes this watch can last long. But the main point of wearing this watch to be identified as nerd. I’m not suggesting to replicate this one, but build your own version. Continue reading