This is an original version of previously posted AVR FFT analyser. It was developed by Chan some time ago and is stil good reference for those who are wiling to build or modify their own FFT analysers.

On SG12232C graphical LCD there are who parts displayed: waveform and spectrum. It really looks cool and real when playing music. The program runs on AVR Atmega8 microcontroller clocked at maximum 16MHz frequency. The signal is passed through 8th-order elliptic filter(anti-alias filter) implemented on MAX293. Hardest part in this project was to implement an FFT algorithm which require lots of processing. But Chan has reached 9.6kHz sampling with 75Hz resolution, what is enough for visualisation. Besides firmware author also provides fixed point FFT library optimized for Atmega microcontrollers so anyone could enjoy creating similar projects.

This AVR fast Fourier Transformation implementation is actually a modification of Chan’s Audio spectrum monitor. Program is implemented on Futurlec Atmega32 control board.

Cemo has adapted this project for 16×16 dot LED matrix display. You can download the entire project from AVRfreaks (including demonstration movie).

When considering new design it is always good to have several references on how to build circuit or interface one or another peripheral device. This one helps interfacing Nokia 3510i LCD display if you need to output graphical information.

Board has ability to adjust voltages for variable targets, including3V, 3.3V, 3.8V, 5V. It is programmable via standard ISP programmer dongle connected to LPT printer interface. Also there are 8 programmable LEDs and 4 buttons for custom applications. It is good reference for your new project or just grab this one as there is also a PCB image available.

Almost every multimeter has ability to capacitance measurement ability, but inductance measurement is included in more advanced or specialized multimeters. Especially if you like to work with RF technologies, power supplies, LC measurement capability is vital. Instead of buying one I suggest to build one and have pleasure to use accurate LCD metter built by yourself.

Design is very simple so it is easy to replicate. It can measure inductances from incredibly small inductance 10nH up to 100mH and capacitance from 0.1pF up to 900nF with auto-ranging capability. Information is displayed on 1×16 LCD module. Zero out button allows to set initial inductance/capacitance for precise measurement. Project page has detailed description on developing LC meter and putting in to nice box. All you have to do is to assemble circuit and flash the program. If you have some troubles in building it, you may buy kit with preprogrammed PIC microcontroller.

This is fun project posted under Reynolds Electronics. This is a microcontroller board which shows temperature and “talks” time.

This module uses EMIC text-to-speech adapter that can be purchased at Parallax. Also it uses DS1620 temperature sensor for reading temperature and DS1307 RTC chip for a digital talking. Module is capable to tel time and temperature in female voice, trigger alarms. This can be nice tool to start programming with CCS C compiler as project code is available in project page.