The following was submitted on July 11th, 2007. Message: I want to combine Ne555 with 74154 IC.The indication of the outputs must be shown with LED's but up to so far it need 15 outputs ,is it possible the way i did? if not i will need your assistance
Mail from CY
LED running lights are used to decorate Christmas Trees, Festival Surroundings and even Buildings. A Clock and a counter are basically required. Many LEDs can be used in parallel with driver transistors. Upto 15 count is is good enough. Many colors can be used and with a PWM or VCO you can make it Audio or Music effects lights like strobe lights.
Multi-Colored LEDs and drivers and even PIC microelectronics with Visual Effects in the form of ROM tables can make Alphabets and Numbers appear in LED arrays. Some have made Mini Ocillosocpes and Toy Spectrum Analyzers too in LED DOT Matrix Arrays. LED Sequencer Circuit
The above circuit is another variation of a basic LED sequencer circuit. Note again the use of the 555 as a clock. The 555 is likely one of the most versatile chips ever invented. The output of the 555 is coupled to a 4017 Decade Counter Divider another very widely used chip
555 and CD4017 Running Lights
The 555 clocks 4017 counter and it counts and Ten LEDs indicate the counts. This can be used as a Sequential timer or for generating staircase waveform.
"I currently have a car stereo set that i use as an amplifier in my living room. but my main problem is that i a lot of noise hum when ever it is on especially when there happens to be a drop in the supply Voltage. i decided to use a voltage regulator and capacitor across (1600uF)...but it only reduced the hum a little. how can i completely eliminate the noise". - Question by FP
Answer by delabs
Ensure that the power supply has a full wave or bridge rectifier. If power supply transformer is say 12-0-12 two diodes must be there and a center tap ground OR If a square or round bridge is used with four leads or four diodes, then it is fine. Half wave rectification or a blown or leaky diode can cause this problem. Put all the filter caps you want and add a series choke as well the better the power supply the audio will be good.
The power supply transformer rating - voltage and current both may need to be boosted. Some very low budget transformers do not use CR-GO plates for lamination (i think it is Cold Rolled Grain Oriented ). They use plain thick metal plates without coating and hence hysteresis and eddy current both cause problems. Then you have ground loop hum and noise of semiconductors, the speaker ground and amplifier ground carry current and they should be directly connected to power supply ground, These you can understand by looking at these pages......
I am only aware of Phillips transistor based designs used 20 years back, but these have more...
details required for... Atmels 89C52 Microcontroller A/D D/A converter Keypad LCD display(Or LED Display) 5V Regulated power supply. Temperature & Humidity controller using PID control algorithm implemented using Atmel's 89C52 microcontroller for a AHU unit ( Analog Input from the sensor(4 wire) 0-10v dc & Output from Microcontroller is 4-20mA to the Actuator through a DAC converter).
The Temperature & Humidity to be controlled are 24±1 degree Celsius and 55%±2% Rh respectively. provide me with good LINKS.
mail from SA
Get a sensor that gives a 0-10V or 4-20mA proportional to RH% and Temp deg C. what you need to do now is to select a A/D and a D/A for a real world interface
Build your own a laboratory instrument for measuring time and temperature. The DigiThermo demonstrates the use of 'C' language, a dual-slope converter, LCD interfacing, and digital filtering as well..
The Assembly language program for this may be the complex, due to PID. and my uC pages micro-delabs also in my other pages you can find theory on PID etc, in them i have MCS51 code for 2 setpoint process controller.
Other uC projects sites links
Temperature and Humidity Meter - This project is a combined temperature and humidity meter. It is an improvement on my PIC-based humidity meter and my PIC and AVR thermometers. I use an ATmega164, which as lots of I/O and memory.
Temperature and humidity measurements with the AVR web-server- The tuxgraphics Ethernet board has a lot of general purpose IO pins where external hardware such as sensors can easily be attached. In this example we use the sensirion sht11 sensor to measure temperature, humidity and calculate the dew point.
One thing tho, i would like to request you to send me some procedures on how to work with surface mount devices (SMD's). I cant get the IC as DIP so i have no choice but improvise an SMD. What is your most professional advice on this? Is it possible you could help me with any procedures for using an SMD on a PCB circuit?.
An SMT component is usually smaller than its through-hole counterpart because it has either smaller leads or no leads at all. It may have short pins or leads of various styles, flat contacts, a matrix of solder balls (BGAs), or terminations on the body of the component.
By Dean F. Poeth, II, Ph.D., P.E., C.Mfg.E.
For the Small Manufacturer and Hobbyist: Prototype Manufacturing, Rework, and Repair Techniques
SMDs have improved performance over through-hole components due to their smaller size, shorter internal leads, and smaller board layouts. These factors reduce the circuit’s parasitic inductance and capacitance. SMDs can also be more cost effective than traditional through-hole components due to the smaller board size, fewer board layers, and fewer holes.
What is Surface Mount Technology? Put Simply - It is a type of electronic component
package. Most electronic components can be divided into two categories - through hole (TH)
and surface mount (SM). Through-hole components have been used for many years and are
designed to be loaded on one side of a printed circuit board (PCB) and soldered on the other.
SM components are designed to be loaded and soldered on the same side of the PCB.
Luke Enriquez. Rev 1.3. August 2001.
VK3EM PO Box 98, Kerrimuir, Vic. 3129. Australia
One of the books here is The " Intersil Hot Ideas" - This was my Mentor Book These helped me build Intelligent Instruments in the 80s. Intersil( GE) was in advanced CMOS before anybody else. They made the smartest chips when the Microprocessors were being examined Skeptically by engineers. (At that time Microprocessors needed many support chips and consumed huge power only later CMOS uC came)
See also delabs Resources i have created as a reference for such doubts (2007)