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Category Archives: 555 Timer

Lead-acid battery desulfator

Posted on October 10, 2013 by R-B Leave a comment

Sulphation is a common problem in lead-acid batteries which usually happens when the battery remains idle for a long period. The sulphuric acid inside the battery react with the electrodes to form sulphate crystals that eventually deposit on the electrodes resulting into sufficient reduction in the efficiency. It has been found from research that the deposited layer of sulphate crystals may be broken down by applying high current pulses to the terminals of the battery. This instructabledescribes a desulfator circuit using 555 timer IC to reverse this process and rejuvenate the battery to like new condition.

Fancy LED Christmas Tree

Posted on December 17, 2012 by R-B Leave a comment

Chris from PyroElectro has posted a tutorial on creating an LED Christmas tree controlled entirely by digital logic. His Christmas tree is cone shaped where 64 LEDs spiral around it from top to bottom. Each LED is individually controllable through a 74HC595 shift register output. The clock for shift register is generated using 555 timer IC. The LED Christmas tree can display two types of patters, one is more predictable and another random. Chris is also running a fund raising campaign on Kickstarter to get support for launching a free online Digital Electronics course. For past few years Chris has been

555 Contest Entry: Music synthesizer

Posted on March 10, 2011 by R-B One comment

A music synthesizer is Frank’s entry to the 555 contest. He used a 555 timer to make a really cool synthesizer that is played with a stylus and has filtering and volume enveloping features. Various note frequencies are generated with precisely calculated resistances.

555 Contest Entry: “Whack a Mole” style game

Posted on March 5, 2011 by R-B One comment

Jim Chen made a very interesting LED chasing game that uses six 556 timer chips. This is his second entry to the 555 contest which is recently closed. There are nine LEDs in the game. Any of them could glow randomly. The player has to turn off the LED by touching an electrode next to the LED. While the player continue playing the game the time available for the player is less and less. When you missed to turn off an LED within the provided time frame, the game is over. Here’s how the game works.

555 Contest Entry: Direct conversion RF receiver for 80 meter amateur band

Posted on March 4, 2011 by R-B Leave a comment

Direct conversion RF receivers are different from the standard superheterodyne one as they don’t have IF stage, and so the radio signals are directly converted into audio signals. This project uses 3 555 timer ICs as the only active devices to construct a direct-conversion radio receiver for the 80 meter amateur radio band.

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