Multimeter on the microcontroller ATMega8

Ohmmeter, capacitance meter, oscilloscope, generator and cymometer – это функции are endowed with device scheme whom I I want to from you Share. After this universal measuring device highly need in practice each Radioamator. A collect him not particularly difficulties even beginners hams.

Driving device

В основе схемы лежит микроконтроллер фирмы ATMEL – ATMega8, который работает на частоте 16 МГц. Информация выводится на стандартный двухстрочный символьный индикатор (16 символов в строке).

Schematic diagram of the multimeter on the microcontroller ATMega8

Just want to say that I am not the author of this development, and do not claim authorship of this scheme. Scheme this device I found online, she found on many sites. It is therefore impossible to determine the source and the name of the author of the project. But still, the author of the scheme I express my great gratitude for the very interesting development!

When I first saw this scheme, it I bought I have my ease and multifunctionality. Since all details I had in stock, then I collected This device one night. Really strongly I wanted see how will be function this priborchik. Honestly speaking, collecting him, I was customized скептически. I do not believe in high accuracy и в широкий интервал измерений емкости и сопротивления. But still nicely It was surprised result. The device fully as specified Interval of measurement with a sufficiently high точностью.

The functionality of the device

• Availability of frequency measurement function with the possibility to change the measurement time and output the value of the frequency and duration on the display;
• The existence of a generator function with the possibility to change the frequency in increments throughout the range 1-100 Hz and output value of frequency and duration on the display;
• The existence of an oscilloscope function-allows to visualize waveform and measure its amplitude value;
• Availability of capacity measurement function allows to measure capacity throughout the range;
• The existence of the resistance measurement function allows you to take in the entire range;
• The presence of voltage measurement function oscilloscope mode;
• Auto calibration mode in modes of measuring capacitance and resistance measurement;
• Availability of generic input cable connector for all five modes of operation;
• The presence of character backlit display size of 2 lines by 16 characters;
• The three control buttons: "rezhimov3 -3" toggle button "button to increase the parameter value" -1 and "parameter value decrease button -2.

Hardware Specifications

• Frequency Hz measuring range 0.1-15000000;
• Range of generation frequency Hz 0-100000;
• The number of pixels horizontally to 16 Pc oscilloscope;
• The number of pixels vertically output for oscilloscope Pc 8;
• Sensitivity range oscilloscope login in 0-5;
• Measuring range, µF capacitance 0.00001-2000;
• Resistance OHM measuring range 1-200 million;
• Supply voltage in 5;
• Рабочая температура 0 … +60ºС.

Modus operandi

Switch on the device the display temporarily (1 sec) a message appears "R" and the appliance will switch to resistance measurement mode. The transition from one mode to another is performed cyclically by pressing switch "3": "R", "dimension", "Oscilloscope", "Generator", "Frequency". When switching from mode is carried out short-term indication of the name of the regime. In the generator mode change the oscillation frequency occurs 1 buttons (increase in frequency) and "2" (reduced frequency). Oscilloscope mode "buttons" 1 "and" 2 "you change time sweep signal level measurement is automatic with indication of its value. In the modes "capacitance" and "resistance measurement» measurement ranges switch happens automatically. Calibration of zero in these modes occurs by pressing and holding the buttons "1", with the subsequent entry in the memory button "2" and calibration value 1000 Ohms or 1000 PF by pressing and holding the button «2» and then burn in the memory button "1".

Changing the time frequency measurement is carried out by pressing "1", which allows to measure the frequency with an accuracy of 0.1 Hz. Time measurement (sec) is indicated in the far right znakomeste top row.

Photo of my device assemblies:

Resistance measurement mode

Measurement of capacitors

Oscilloscope

Generator

Frequency

The printed circuit board inside the housing

When the microcontroller firmware fjuzy set as follows:Additional materials (proven pproshivka, PCB lay format):

[hidepost]Download Microcontroller firmware
Download печатную плату в формате .lay [/hidepost]

For those who want to repeat this unit spread the sticker on the front panel

Автор: Киричик С.