Cat feed time with Auto-dine

If you are a cat lower then probably it is more pleasure to feed it by yourself. Otherwise if there still a cat in your house and needs to be fed, then leave this job for automated cat feeder that is controlled by ATmega8 microcontroller. The concept is pretty obvious – microcontroller counts time, that is shown in LCD screen along with next feed time. There are couple buttons to adjust the feed time settings. When feed time occurs servo motor opens food dispenser that pours food in to a bowl. I bet cat loves this toy and thinks how to hack it to serve food more often : ) Continue reading

AVR based audio Spectrum Analyzer

The AVR Acoustic Spectrum Analyzer is a device that you need to have if you want to improve the audio quality of your audio equipment. This acoustic spectrum analyzer is created on the technical aspects of the Atmega8 AVR microcontroller and an amplifier that is operational. You can install this analyzer on your PC, external speakers, car radio or any other device whose sound you want improved. The AVR acoustic spectrum analyzer supports displays such as 20*4, 20*2, 16*2 and 24*2. The settings of this spectrum analyzer are normally saved in the eeprom memory. If you want to alter certain settings, such as the brightness of the display, you can fix a keyboard to do so. You can also use the keyboard if you want to change the display effect or even its sensitivity. The Analyzer can be used on any VFD or LCD that is compatible with HD44780. All you need to do is to connect the AVR Acoustic Spectrum analyzer with the audio signal and you will like what you hear. You also need to AVR analyzer to… Continue reading

Measure current of your car alternator

Have you ever wondered how much electric current your truck/car uses? It is always interesting to know things that isn’t displayed in front panel. Measuring alternator current can also have practical means – it allows detecting failures, or simply helps in right alternator selection as high output alternator isn’t always a best choice. Josh used a hall-effect current sensor from Allegro Microsystems which is capable of measuring currents up to 150A and outputs pretty linear 0-5V signal which can be directly fed to microcontroller. He came up with pretty simple circuit where AVR Atmega8 microcontroller reads sensor data via ADC input and sends data through RS232 interface to PC where data can be analysed in convenient way. I wouldn’t mind to add a simple display near the dash-board. From my practical perspective – it wouldn’t hurt to add another sensor for car batteries. It may be actual for older vehicles with diesel engines. I noticed that before engine start the lamp, indicating “Glow Plugs on”, turns off before the pugs actually goes off, and starting engine too early really hurts… Continue reading

WhereAVR – lightweight APRS tracker

This small AVR based APRS tracker is designed to be used in balloon. Tracker can be interfaced with GPS receiver; also it has several analog and digital I/O where various sensors can be attached. WhereAVR has ability to decode ax.25 packets, what allows reception of remote commands like real TNC does. Board itself is built around ATmega8 microcontroller which has all necessary functions built in. Tracker is able to generate 1200-baud audio signal which is used to modulate carrier radio signal. I also have a zero-crossing audio signal detector. And of course what tracker would be without GPS module. Module was put on a test where balloon flew above 90000ft. It worked fine … but its gone somewhere over Atlantic. Nice project to learn from. Author provides all necessary files in case you want to repeat his experiment. Continue reading