During spare time I made quick design of TTL to RS232 adapter, that works with my AVR development board. This adapter helps to connect TTL (Transistor-Transistor Logic) level signals to RS232 interface. TTL side is 9-pin female connector and RS232 sire is male connector.
Unit is powered from target board using power pins.
The RS232 TTL adapter [...]

Usually we are used to connect LCD displays to 5V systems. As LCD controllers usually require 5V power supply there must be some compliant circuitry used when interfacing to 3V systems like ARM LPC2000 microcontrollers and so on.
Here are few examples how this problem could be solved.
Solution number1:

Standard LCD microcontroller can work with lowered power [...]

Usually keyboard is connected by using matrix type of connection – rows and columns. For instance for 12 button keyboard wee need 3+4 digital inputs of microcontroller. There is a way to build keyboard and connect to microcontroller using only one wire. For this we will need only signal wire, power and ground and of [...]

As SD and MMC cards are popular because of their simple SPI interface. It is ease to interface SD/MMC cards using any microcontroller. SD/MMC card storage may serve in many purposes like data logging storage , voice data banks, or store other information. There are a lot of free drivers available for for microcontrollers like [...]

What is compilation of program maybe it is more or less clear. But what is program linking? I am sure many beginners heard of this but done exactly know what it is. In a few words I can say, that linker creates an output file from relocatable objects.
Compiler is not one big program. It usually [...]

Sound wave can be sensed by using sound sensor. If you are designing some kind of robot, sometimes it is useful to enable sensing of sound. Then you can program your robot to follow your voice commands. In some cases sound wave sensors are used as collision sensors. Sound wave sensor is a microphone. Microphone [...]

IrDA is a transmission standard commonly used in computer and peripherals like mobile phones. The basic purpose of IrDA is to provide device-to-device communication over short distances. IrDA solves the problem of usage cables, that may differ from machine to machine. With IrDA no cables are required so this is easy to connect same device [...]

Clockless CPUs are so called asynchronous CPUs where are not clock generator needed which clocks every synchronous operation. Asynchronous processors gives results not after defined number of clocks, but after it finishes operations. This is a key of effective usage of energy and asynchronous processors generates less noise than synchronous.
Asynchronous processors have couple advantages against [...]

RTOS – Real Time Operating system is a program environment which interfaces hardware and desired tasks. RTOS usually has built in set of services (interfaces and functions) which allow to interact between tasks and hardware. Because most low level functions are performed by RTOS realisation of programs becomes much easier.
What is difference between Embedded RTOS [...]

Every time you are making some circuit or more complex system, you always do some testing to make sure that your electronic “baby” is working properly and you can expose it to publicity. Lets say you are constructing some kind of robot. Then typical list of testing task may be as follows:

Stability tests using various [...]