Dual color (4 line x 3 column) led, 12 white and 12 blue are intermittently switched controlled by two NPN transistors BC337. The speed and duty/cycle timing of lighting duration is determined by NE555 oscilator. The number of repetition of sequential lighting of each group of led is determined by 5-stage divide-by-10 Johnson counter with [...]

Nowadays is so easy to build precision digital LC meter with LCD display and microcontrollers.But, what about 1997? There is my first very precision ANALOG LC METER. Look at this, butdo not fall in love in retro princess from past!!The analog LC-meter project (AP-LC1) have more then 3% accuracy. Really!There is no balanced bridge, or [...]

It’s a new Mini GSM localizer without GPS using a low cost GSM module: the SIM900. This system allows for localization without directly using GPS technology; we are able to locate the desired object fairly precisely by using database availability together with the geographic position of the cells themselves. In some country the cell coordinates [...]

After the electromechanical timer on [Paul Canello's] washing machine broke for the third time he decided he needed to stop repairing it and find a more permanent fix. He decided to build his own microcontroller-based system for washing his clothes. The controller on a washing machine is nothing more than a mechanical alarm clock. It [...]

If you hate paying big roaming bills while traveling but still want to use your current GSM phone number to receive/make calls (and SMS) then consider using Skype in combination with this piece of free software and a cheap USB GSM/GPRS modem. This device (software actually) is also useful if your country is not in [...]

The project is designed to control an heating system in order to keep the temperature in a room above a certain value, which can be set from Internet or a Personal Computer by LAN, because ours is not a simple thermostat but a complex unit managed by Arduino, which can connect to a local network [...]

The presented digital timer is built in addition to the before mentioned ultraviolet light box.Indication is on 4 digits seven segment LED display.The timer counting backwards from 99 minutes and 59 seconds to 00:00.It is built with microcontroller PIC 16F84A and integrated circuit CD4511.Supply for the ultraviolet LED diodes are terminated with the help of [...]

This project slightly modifies the Google Android sample app called "Bluetooth Chat" so you can type a message in the Android app and that same message will appear on an LCD attached to an Arduino Uno.   Source: circuit_breaker

Long jealously kept electricity scheme for testing electrolytic capacitors, finally the pages of the Emitters.ESR-meter (Electrolytic serial resistance), an electronic instrument for measuring the degree of freshness (dry) of electrolyte fluid in capacitors, without dislocation of the experimental component of the printed plate.The device is built in miniature version on the two PCB, in addition [...]

This transmitter design is usually attributed to Japanese multimedia artist Tetsuo Kogawa. It takes audio input via 1 / 4 “phono jack, and built as shown, without additional antenna connection, will emit a radio signal about 30 feet.This is a standard model Mr Kogawa is the simplest FM transmitter, which is slightly more complex than [...]

After having seen so many propeller clockPOV videos on Youtube, but no real description of how they work or how to build your own, Chris made one also and documents how it was built. The Pyro Propeller Clock POV design criteria was short and sweet: be as simple as possible in order to encourage others [...]