This is design for a frequency meter based on AVR microcontrollers. Maximum input frequency is specified to be 30 MHz in the multi-chip configuration, and in single-chip configuration, there are both 5 MHz and 10 Mhz versions operating with 10 and 20 MHz crystals, respectively. All versions have 9 1/2 digit resolution. I have used […]
A Little More Serious Frequency Meter using ATtiny2313 microcontroller Read More »
Its built into a plastic project box with an aluminum cover (on the bottom). The controls are as follows: Large golden knob is coarse tuning, small black knob with a blue index stripe is fine tuning, the green LED is the power on indicator, the slide switch is the on/off switch. The small black knob
HF/VHF/UHF TEST OSCILLATOR using microcontroller Read More »
I needed a way to measure hand-wound RF inductors in my second lab, and since I would only be doing this occasionally, I didn’t need anything fancy, and since once a friend finishes his AT90S1200-based design, I plan to make one myself, I figured I’d use this for less than a year, so I didn’t
RF Inductance Meter using microcontroller Read More »
A well known L/C measurement circuit is pressed into service to make a bare bones measurement circuit. Download the AVRStudio assembly source: lgm031227I.asm. Download the AVRStudio hex file: lgm031227.hex. Left-to-right: The 5 volt regulator, the LM393 oscillator (a 0.047 uf capacitor is mounted on the LC circuit connector), the AT90S2313, and the serial connector to
LC Determination by Resonant Frequency Measurement using microcontroller Read More »
The “Battery Good” checker. When the button is pressed, the green LED will glow if the battery voltage is above the preset threshold. This version has a higher parts count than the “Battery Low” version, but a bonus is that it can drive an LED to be very bright, and the luminance is independent of
Battery Checker Circuits using microcontroller Read More »
1 Khz From a Quartz Crystal 1 V P-P Sine Wave Calibrated Output 1 KHz Square Wave Output 900 mv Inverted Sine Wave Output (Uncalibrated) Downloads Download the WINAVR main source for the 2313 version of the firmware: 2313sine.c. Download the complete zipped WINAVR project for the 2313 version of the firmware: 1_kHz_sine_2313.zip. Also, Download
A 1 Khz Digital Sine Wave Signal Source using ATmega8515 microcontroller Read More »
A related article on this site: True RMS-To-DC Adaptor for DVM Introduction This project came about when I needed to perform some reliability tests on some headphones according to IEC 268-7. The test requires operating the headphones at their rated input power for a number of hours using clipped pink noise, and muting the noise
A Noise Generator per IEC 268-1, IEC 268-5, and IEC 268-7 Read More »
Take Maxim’s MAX038 function generator chip, add some frills, and you have a pretty nice tool for the bench. Downloads: Main Circuit Schematic Power Supply Schematic You can build this with switches instead of buttons if you don’t want to use a micro controller. Here is the controller code. AVRStudio 4.x Assembler Source for AT90S1200A
MAX038-Based Sweep/Function Generator With Markers using AVR ATtiny2313 microcontroller Read More »
This is a means of testing AC mains operated circuits at variable AC voltages, and it also provides isolation to allow safe measurements of that circuit. A fused isolation transformer and a variable auto transformer connected together in a grounded, fire safe box. What more could you ask? Find updates at www.projects.cappels.org Introduction
An Isolated Adjustable Auto transformer using microcontroller Read More »
Downloads Download the AVRStudio assembly source for the program: M8DPM091109A.asm Download the AVRStudio hex file: M8DPM091109A.hex Find updates at www.projects.cappels.org Overview – A 10 bit digital panel meter for positive voltage only. – Input resistance: about 130k – Ranges: 0 to 10.20 volts and 0 to 102.3 volts. – Over range indication. This project came
A 10 Bit LED Digital Panel Meter With Auto Ranging Based On The ATMEGA8 Read More »
