20 Band Audio Spectrum Analyzer

PIC-based Central Heating Programmer

Central heating systems has been a good solution for many homes and even offices for quite some time now. If you own such a system I’m sure you would like to be able to control it remotely from your bed or even from a computer. This project presents such a controller. It has a 5/2 days programmer, that is 5 week days, 2 weekend days or for entire week.

The control panel allows you to turn on and off heat and hot water independently. It has 10 program entries that you can save and you have the possibility to manually override the program. Basically it is composed of two modules: the relay module that is placed at the boiler, which also has the 9 pin D connector for serial connection and the programmer panel which is connected to the relay module by a UTP cable.

The programmer panel has a 2×16 LCD display and five switches to select the desired program or manually control the central heating. PIC16F628A microcontroller was used in this project as the system’s brain. Dallas DS1307 was used for time management and for saving time settings in its memory. It is powered by a backup battery so it will not lose the memory data when mains power is taken. Max202 IC takes care of the serial communication.

Because of the UTP wire lenght the rellay output of the PIC can not drive the rellays directly, so a driver is used from Quasar Electronics. It is also a good idea to use protection diodes on those outputs to take care of spikes.

LCD will show the current operation mode for central heating and hot water, the on/ off state and the time. Switch 1 and 2 turns the system on/off , switches 3 and 4 are used for manual control and switch 5 is used for programmer setup. A detailed explanation of the programmer’s operation is presented in the link with all schematics and construction procedures as well as the software for the microcontroller.


PIC-based Central Heating Controller: [Link]

Arduino Control Panel For Motorcycles

As the modern day motor vehicles grow in complexity, the need for measuring various locomotion parameters is something that all manufacturers approach, regardless of the purpose, size or price of the vehicle. Motorcycles make no exception, especially with the need for speed of most bike enthusiasts.

A project for all motorcycle-loving geeks out there, the Arduino Control Panel for Motorcycles is still in the prototype phase, but it seems to be working flawlessly. It currently has a speedometer and a tachometer which are very accurate and also a gear indicator . It uses a standard Arduino, a small LCD and Bluetooth and it is powered by the motorcycle battery.

The device is connected to the electrical system of the bike, receiving pulses from the tachometer circuit and using a reed switch for wheel rotation. It calculates the wheel speed in RPM and divides it into most recent engine RPM, obtaining a unique ratio for each gear. This is done by counting how many times the engine turns while the wheel turns once and the answer is somewhere between 4 and 12 for 5th gear and 1st gear, respectively. An interesting aspect of the coding is the interrupt handling, which is done by logging every 10th one.

As with all prototypes, this is not the final version of the project. The designer plans to make the device smaller and to incorporate it into the tank console and also to enhance it with more functions, like wind resistance. Not sure about the usefulness of the whole thing, as all bike producers install similar equipment, especially on newer models. Still, an interesting project that could be further developed.

Arduino Control Panel for Motorcycles: [Link][Via]

May 30th, 2009

Digital Thermometer

Digital Thermometer

Here is a very good looking thermometer project showing the reading as a discrete value and as a bar-graph on a LCD. The idea is simple, we have a sensor, the LM35, who outputs a voltage depending on the ambient temperature, LM35′s rating is 10mV/ degree Celsius. Since the sensor’s output is analog we need to convert it to digital in order to display the value on LCD. The ATmega8 microcontroller will handle the A/D conversion, with a 4.8mV resolution it is within the accuracy range of the sensor.

Once the LM35′s output has been converted to digital, the microcontroller will make the calculations necessary to determine the temperature and display that value. The LCD is a 20×4 type so the bar-graph will show 20 levels. ATmega8′s port C0  reads the analog data from the sensor and port D controls the LCD. The code was written in BASCOM AVR which has some built-in functions to handle the A/D converter of the microcontroller. For Fahrenheit measurement use LM34 sensor.

All in all it is easy to build, as a school project perhaps,  with possibility for upgrade, for example to be able to change the bar-graph’s scale.


Digital Thermometer: [Link]

March 7th, 2009

Universal remote control

Universal remote control

Are you tired of carrying around one remote for the TV, one for the DVD player, one for the sound system and the list can go on. There is the possibility to buy one “good for all” remote control but it will cost you a few hundred dollars, off course there is an alternative for less money, make your own DIY universal remote control.

Any valid RC5/RC6 will be displayed on the LCD, and any code can be sent with the on board IR led’s, the LCD is the common 2×16 HD44780 compatible type.

The hardware is very simple, the software is written in basic and made available by the author. The Dell TV deals page sometimes has universal remotes like the Logitech Harmony One for heavily discounted prices.

I recommend this project for those interested about the RC5/RC6 codes, it can be a great alternative for radio based remote control for robotics, as you can see in one of my previous articles: IR remote robot

Universal remote control: [Link]

February 28th, 2009

Head mount display hack

Head mount display hack

Ever wondered what’s inside a head mounted spy gadget? Well, now you have the answer, there was somebody curios enough to take apart a robot toy which had a camera and eye piece, considering the size, isn’t a James Bond type of gadget so don’t expect to find any nanotechnology inside, but you can see how the LCD displays work. Even your LCD monitor uses the same solutions, only in bigger.

Head mount display hack inside

This post is for people curios enough to dismount  similar electronics, my advice : don’t, you won’t find any components inside which you can use, or there are hard to remove from the pcb and if you damage the flexible pcb or any other part, you probably can’t repair it

Head mount display hack: [Link]



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