Giorgos Lazaridis writes:
Some time ago i uploaded a breathing LED circuit with the 555 timer chip. It became very popular and i received many comments and emails with people that made this circuit and worked fine, as well as comments with people that had troubles converting it to operate at 12 volts supply. It was designed to operate with 5 volts, because i plan to use it for a future PC mod. Since the PC power supply has 5 volts output, and since the LEDs that i plan to use require 3.8 volts to operate, choosing 5 volts for supply was the best choice to minimize power dissipation on the transistor.
Converting the original circuit to operate at 12 volts is not a big deal, but it requires some transistor knowledge. The only parts that should be changed were the biasing resistors R4 and R5. But i decided to take it one step further. I decided to make a more flexible breathing circuit. The new version as 2 more functions: It has an adjustable voltage oscillation amplitude, and an adjustable output DC offset. What this means is that it can be easily adjusted to operate with different LEDs. If for example the load is a 12V LED strip with operating voltage range 8 to 12 volts, the circuit can be adjusted to provide exactly this: 8 to 12 volts output. Similarly, it can be adjusted to operate with a high brightness LED that has voltage range from 2.4 to 3.8 volts.
Flexible 555 LED Pulsing (Breathing) Circuit - [Link]
Giorgos Lazaridis writes:
During this very long period that my PC went bad, i had the time to do many thing like finishing the PC case mod that i began like two years ago… So i connected the power button, the reset button and the audio controls. The rotary encoder will be used for my next project that will be a gigantic scriptable 8-channel PC fan controller.
Now, regarding the power button, it has a blue LED that light when the HDDs are operating (write or read process). The effect is very cool, but i want to make it cooler. I want the LED to blink when the HDDs are used, and when no Read/Write operation occurs i want the LED to breath. A breathing LED is the effect that the LED turns on and off by fading in and fading out, which gives the feeling of “breathing”…
A 555 Breathing (Pulsing) LED - [Link]
Rob writes in… [via]
I’ve seen quite a few hacks related to controlling appliances, lights, etc over the years and just wanted to share a little info so that everyone has access to a cheap way to do it relatively safely. By trade I work in the building controls/integration industry and as a result I use these relays at work and at home(chicken coop control,light,etc)quite a bit.
The interface between your microcontroller of choice and the relay is a simple 555 relay driver circuit. I have included the pdf that inspired me to do it this way. The relay I use is the RIBTU1C. The reason I prefer this relay is that the coil will run on 9VC @ 20mA and the contacts will switch 10A @ 120VAC. Total cost for the RIB and a 555 is under $15 if you shop around. In addition the RIB has a partition inside the box between the line and control sides. There’s also room for a Radio Shack breadboard in there!
Safety First! Switching 120vac loads with a microcontroller - [Link]
Something that a project that I’m working on has me doing is using a serial to parallel IC (think 74HC595) to control leds. However, rather than drive the leds directly from the pins, I opted for the use of transistors. After testing this out, it became apparent to me that perhaps the leds might be too bright, so I went in search of a simple PWM generator.
Yet Another Simple Pot-controlled 555 PWM generator – [Link]
Valentin B — 555 Inductivity Meter
555 Contest Winners Announced – [Link]
dangerousprototypes.com writes: [via]
What’s in a name? David L. Jones of EEVBlog thinks he’s found an Easter egg in the performance characteristics of the 555 timer chip which reveals the basis of the “555″ in its name. Build his circuit (schematic at video 13:25), fire up the scope and see if you agree!
555 timer Easter egg? - [Link]
I needed a variable slow speed clock to help me debug a design I’m creating with a bunch of CPLDs. Given the current focus on the venerable 555 timer IC, I thought rather than using my usual AVR/PIC solution I’d create something with the handy little timer.
555 based FPGA/CPLD debugging oscillator - [Link]
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. [via]
555 Contest Entry: Music synthesizer – [Link]
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. [via]
555 Contest Entry: “Whack a Mole” style game – [Link]