Control LCD Module Control Using PC

Here’s a design circuit for simple circuit controls a popular 2-line x 16-character LCD by a PC via printer port. It doesn't use the Bi-directional feature found on newer printer ports, thus it should work with most, if not all Parallel Ports. These LCD Modules are very common these days, and are quite simple to work with, as all the logic required to run them is on board. This is the figure of the circuit;

The LCD panel's Enable and Register Select is connected to the Control Port. The Control Port is an open collector/open drain output. While most Parallel Ports have internal pull-up resistors, there are a few which don't. Therefore by incorporating the two 10K external pull up resistors, the circuit is more portable for a wider range of computers, some of which may have no internal pull up resistors. The 10k Potentiometer controls the contrast of the LCD panel. The software source code has been written in Borland C++.

read more "Control LCD Module Control Using PC"

Control Counter Wall 7 Segment Circuit

This is a design circuit that is simple counter can be used to count pulses, as the basis for a customer counter (like you see at the doors of some stores), or for anything else that may be counted. The circuit accepts any TTL compatible logic signal, and can be expanded easily. This is the figure of the circuit;

 
All pulses to be counted are to be TTL compatible. They should not exeed 5V and not fall below ground. You can add more digits by building a second (or third, or fourth, etc…) circuit and connecting the pin 11-6 junction of the 74LS90 and 74LS47 to pin 14 of the 74LS90 in the other circuit. You can keep expanding this way to as many digits as you want.

read more "Control Counter Wall 7 Segment Circuit"

Control Using Reset IC in Microcontroller

This is a the design of microcontroller based electronics project, the use of Reset IC is critical for highly critical applications that need to ensure that the MCU will only operate at its optimum voltage. Without the use of reset circuitry, the MCU may go into a tristate of which it may go into abnormal operation. This is the figure if the circuit;

During power up, once Vcc exceeds the reset threshold, the reset line will be kept low for a period after which the line will be pulled high. This resets the MCU afterwhich it will go into normal operation.
 

If the Vcc drops below the reset threshold, the reset pin will go low. It will stay low for at least the reset time out period and go back to high again. This operation will ensure that the MCU power supply is monitored and will only go into operation when the Vcc is within the range of its operation. The threshold voltage of the IC is chosen based on the minimum Vcc of the MCU. MCU supply can range from 1.8V to 5.0V and a suitable IC can be chosen to monitor the supply voltage to the MCU.

read more "Control Using Reset IC in Microcontroller"

Control TEA6320 Multichannel Audio Selector and Volume Control Circuit

This is a design circuit for high-end audio equipments are normally digitally controlled by a microprocessor (microcontroller) system. It’s necessary to have  digital interface that provide control for audio signal switching, as well as programming the gain to control the signal volume. This is the figure of the circuit;

 

TEA6320 comes with the solution for digital control of audio source channel selector and volume control, very useful integrated circuit for modern audio or stereo application with embedded digital control. For more information on how to use this audio signal control IC chip, see the datasheet.

read more "Control TEA6320 Multichannel Audio Selector and Volume Control Circuit"