Friday, July 30, 2010

Versatile Central Heating Program Controller using PIC16F628A

This central heating program controller is designed to use with a heating boiler. The two relays control the supply of hot water and heating. It has a front panel switch control with a 16x2 LCD screen. It also provides a serial interface that allows to be operated remotely from a PC.

The programmer and boiler control relays are contained in separate units so that the relays can be located close to the boiler while the programmer itself can be located anywhere in the house using low voltage connections back to the relay unit. Besides you can also make a serial interface connection local to the programmer in which case you only need 4 wires for power and relay controls.

* Independent control for heating and hot water.
* 10 flexible program entries.
* Programs can be set to operate Mon-Fri / Sat-Sun / Mon-Sun.
* Manual advance for water and heating
* Water and heating can be independently set to manual or programmed control.
* Operation and setup from front panel or remote serial CLI
* Battery backup for Real Time Clock (RTC), program settings and manual control.
* Programmer can be located remotely from boiler using low voltage signals over CAT5 or 6-core alarm cable.
* RS232 serial interface with command line interface allows full control and setting from any computer.
* Front panel control can be locked-out from serial CLI
* Based on Microchip PIC 16F628A microcontroller

Tuesday, July 27, 2010

Interface a SD Memory Card to ATmega8 with FAT32 Implementation

Some applications of microcontrollers like data loggers require a bulk of data storage and the internal EEPROM memory may not be sufficient. In such cases, use of SD memory card is a much cheaper solution.

This project demonstrates how to interface a SD card to ATmega8 microcontroller and transfer data (both in raw and FAT32 format) between the two. The data read from the SD card are transferred to a PC through RS232 connection and displayed on a Hyper-terminal window. Similarly, to write data to card, the data was fed through HyperTerminal, by typing some text.

For firmware and other details: SD/SDHC Card Interfacing with ATmega8

Monday, July 26, 2010

Ultrasonic Parking Aid

Parking your vehicle in a narrow space is always a risk. This parking aid project from Cornell university students will help you to prevent your Mercedes from getting scratched while parking in a tight space. This ultrasonic ParKontroller can sense how far you are away from the wall or a hidden object behind your car and warn you visually and audibly using LEDs and speaker respectively.

The students use the principles of Sound Navigation and Ranging (SONAR) technique in this design. This principle is used for finding the distance and direction of a remote object underwater by transmitting sound waves and detecting reflections from it. First, a series of short ultrasonic pulses are transmitted using a transducer that changes voltage into sound waves.


This parking aid device can detect an object within a range of 40cm with accuracy of 1cm in the distance interval of 15 to 40cm. For more details, visit: Ultrasonic Parking Aid.

Thursday, July 22, 2010

LCD Thermometer using Atmega8 and LM35.

Atmega8 is a popular 8-bit microcontroller from ATMEL. It has 8KB self-programming Flash Program Memory, 1KB SRAM, 512 Byte EEPROM, 6 or 8 Channel 10-bit A/D-converter. Up to 16 MIPS throughput at 16 Mhz. 2.7 - 5.5 Volt operation. The LM35 of National Semiconductors that is used in this project is a precision centigrade temperature sensor, which has an analog output voltage. It has a range of -55ºC to +150ºC and a accuracy of ±0.5ºC . The output voltage is 10mV/ºC . The output voltage is converted by the AD convertor of the AT Mega8. The temperature is displayed on an LCD module.

For circuits and software, CLICK HERE.

ATtiny 2313 Development Board

ATtiny2313 is a successor of the 1200 and is designed to address the requirements of battery operated and portable applications by offering low power consumption and a high level of system integration in a small package. Here is a development board for the beginners.For PCB and Programming software, Click HERE.

Sunday, July 11, 2010

Make your own Variable DC Power Supply

A variable DC power supply is the most useful tool on a hobbyist's workbench, because different electronics projects sometime require different DC supply. National semiconductor's LM350 IC can provide a variable DC voltage ranging from 1.25 to 33V with the use of just two external resistors. It can provide current up to 3.0A if properly heat-sinked.

This project uses a LM350 IC to generate a variable DC voltage from 1.25-18V. My finished product looks like this.

For more details about this project, visit this.

Saturday, July 10, 2010

Interface 16x2 LCD to a PIC microcontroller using C

Liquid crystal displays (LCDs) are more convenient ways of displaying output results in any microcontroller based projects. If you are new to microcontroller interfacing, and want to learn how to interface a LCD to a PIC microcontroller you need to look at this. Here you will find PIC16F628A interfacing with a 16x2 LCD display and the programming is done in mikroC.

The objective of this experiment is to interface a 16x2 LCD to PIC16F628A in 4-bit mode. This means the data transfer will use only four pins of the microcontroller. There is no additional hardware setup needed for this experiment, as we have a ready-made LCD interface female ......
Click here for more details.

PIC12F683 Development Board

If you have never tried PIC microcontrollers, you can start with Microchip's 8-pin PICs. One of the most versatile type is PIC12F683. It is a 8-pin Flash based, 8bit RISC microcontroller from Microchip. This little PIC microcontroller offers up to 6 I/O pins (the remaining two are power supply pins). It needs no external oscillator, as it has an in-built oscillator with software selectable frequency from 8 MHz to 125 KHz. It also offers a feature that allows external signals to wake it upfrom the sleep state.

If you want to explore the feature of this microcontroller, here is a set of complete circuit diagrams and test projects. Visit this for more details.