Dave celebrates the classic 555 timer IC by building the Evil Mad Scientist “three fives” discrete timer kit. Some scope measurements and an explanation of the internal 555 timer circuitry follow.
EEVblog #555 – 555 Timer Kit - [Link]
Kerry Wong documented his VFD filament driver built:
I recently salvaged a vacuum fluorescent display (VFD) from a piece of old test gear. The VFD is a 13 digit 7-segment multiplexed display and I thought it would look great in a custom digital clock or something similar. While it has the model number FUTABA 13-MT-54NA, I could not find any information on the internet specifically for this model. Of course, before I could put this vacuum fluorescent display to use in my final project, I needed to first build a driver circuit to drive this display.
VFD filament driver using 555 - [Link]
JN Lygouras, University of Thrace writes:
The control circuit in Figure 1a allows you to manually adjust the power delivered to a load. By changing the setting of potentiometer R3, you change the phase angle at which the thyristor (Q3) fires (Figure 1b), thereby altering the load current’s duty cycle. The adjustment range is about 0 to 180°. Q3’s off time is linear with R3, but of course the resulting load power is not linear with R3.
555 timer triggers phase-control circuit - [Link]
Kennith needed a 1A constant current lead-acid battery charger for his HAM radios so he writes:
Since the SLAs are relatively small, and I only need them charged between radio outings, I opted to build a 1A constant current charger, based on the 555 Battery Charger which won first place in the 555 Design Contest Utility category. Using a 555 is a rather clever way to get two comparators and a Set-Reset latch in a single 8DIP package, which is needed for the high and low trip points. The major difference between my design and Mike’s is that instead of using a relay like him, I use an LM317 as a constant current source to limit my batteries charge rate.
555 based constant current lead-acid battery charger - [Link]
This project is an all-digital-hardware LED Christmas tree we’re calling the Christmas Tree O’Digital Logic. The tree itself is composed of 64 LEDs built into a spiral sitting on a piece of protoboard. Underneath, the controller uses shift registers and a 555 timer to create two modes of display: a predictable pattern and a random pattern. This should light up any desk or shelf and bring merriment to you.
Christmas Tree O’Digital Logic - [Link]
This is an all-digital-hardware Theremin. The Digital IR Theremin uses comparators, digital logic and a single 555 timer for tone generation to make it so that when you wave your hand in front of the infrared proximity sensor, it outputs a tone with varying pitch depending on how far away your hand is from the sensor!
Digital IR Theremin - [Link]
Last month one of the unsung heroes of electronics has passed away. Hans Camenzind, father of one of the most famous integrated circuit of all times, the Signetics timer NE555, timed out at the age of 78. Being a gifted analog designer, Swiss-born Monsieur Camenzind is also credited to be the father of class-D amplifiers and he has introduced the concept of the Phase-Locked Loop (PLL) in ICs. During his rather productive career he designed over 140 ICs, wrote several books and many articles and his name is attached to some twenty patents.
When a famous artists dies you will hear his or her greatest hits on every radio or see his or her best films on every TV channel. Therefore, in respect of one of the great electronics inventors of our century we will play here Hans Camenzind’s most successful composition, NE555 in bipolar. [via]
Hans Camenzind, father of the NE555, dies at the age of 78 - [Link]
This GM-Counter is build on 2 PCB’s. One is a standard high Voltage generating circuit, whilst the second is a Counter based on an ATMega16™ which also handles serial Communication with a host (Environmental Control).
The High Voltage generator is based on a 100 Hz Chopper, which is build around a ‘555’ in combination with a standard Transformer and a Cascade to achieve Voltages from 400 to approx 900 V. (adjustable) The Regulation is just on-off (Burst) which will result in approx 1% Drift. This Circuit consumes about 20 mA at a 9 V (Battery). (more when starting up
Homebrew Geiger Müller Counter - [Link]
Here is a rather simple but practical use for digital electronics…..dice! (or in the case a single die)
Unlike many of the kits found online this one does not use a micro controller. The entire circuit is based around 74LSxx logic ICs and a 555 timer for a clock.
7400 competition entry: Digital die (74XX Family) - [Link]
Arup wrote a guest post about his Nokia LCD breakout board:
I designed a simple Nokia LCD Breakout board which allows you to interface any Nokia 6100 compatible display to microcontroller like PIC and AVR. The board itself provides 6.8volts for the backlight by a simple boost converter built up using a common 555 timer IC. There’s a switch to choose whether you want to work with 5V logic, or with 3.3V logic. [via]
Simple Nokia LCD breakout board - [Link]