Here I will highlight some features of C language commonly used in 8 bit embedded platforms like 8051, AVR and PICs. While programming microcontrollers in C most of the time we have to deal with registers. Most common tasks are setting and clearing bits in a register and check whether a bit is 0 or 1 in a given register.
Servo motors are a type of electromechanical actuators that do not rotate continuously like DC/AC or stepper motors, rather they used to position and hold some object. They are used where continuous rotation is not required so they are not used to drive wheels (unless a servo is modified). In contrast they are used where something is needed to move to particular position and then stopped and hold there.
Accelerometers are recently developed solid state electronics devices that makes it very easy to measure acceleration. They are completely modular and very tiny devices which gives voltage proportional to acceleration. These type are called analog accelerometers as their output is voltage.
Inter IC Communication or I2C is a two wire serial communication bus used to connect a variety of external peripheral with a microcontroller. Most common are EEPROMs, RTC, Port Expanders etc. Most leading MCUs comes with at least one dedicated I2C host adaptor built in.
RFID is a great technology, has may uses and become very cheap and easy to implement these days. Very interesting and useful project can be made by using RFID technology. In our tutorial series on RFID we will get introduced to this magical technology and practically create RFID based solutions.
The DS18B20 Digital Thermometer provides 9 to 12–bit centigrade temperature measurements and has an alarm function with nonvolatile user-programmable upper and lower trigger points. The DS18B20 communicates over a 1-Wire bus that by definition requires only one data line (and gound) for communication with a central microprocessor.
An advantage of using the microcontroller to generate the PWM signal for us is that once it has been set up correctly the PWM signal will continue to be generated for us automatically in the background. We don't need to write any complicated interrupt routine or other timing code. The beauty is that by simply changing the comparator value we can alter the duty cycle of the PWM until such time as we decide to modify it again.
Piezo buzzers can be attached directly to a microcontroller pin by connecting the red wire to the output pin and the black wire to ground. If your output pin is set high then there is a voltage across the sounder - but this won't make a noise. A sounder needs to be turned on and off in rapid succession to make a tone.
Interfacing a PS/2 type keyboard (or a USB keyboard) is very simple. This page shows you how to do a simple interface using the ASCII characters, or a full interface to all of the keys on the keyboard.The PS/2 interface requires +5V and ground, data and clock, on a 6-pin female mini-DIN connector.
With this circuit we can controll up to 8 devices (4 devices in our example project), by sending a specific SMS message with any mobile phone. If you have an old ericsson mobile phone and you are not using it, its the time to build some useful tool with it. The controlling that we can do to the devices, it is ON , OFF or Reset.