Category Archives: measurement

Tektronix RSA306 IF frequency verification

KF5OBS writes: After posting the teardown video of the Tektronix RSA306 USB 3.0 Spectrum Analyzer on my YouTube channel, someone asked me to verify that the IF sampled by the Linear Technology 14-Bit / 125 Msps ADC is really at 140 MHz. Using the Tektronix MDO4104B-6 and a passive RF probe, I gladly did so.

Using the cirrus logic CS5464 for AC current measurement

Using the cirrus logic CS5464 for AC current measurement by Corgi-Tronics: Continuing the series on examining devices to measure AC current, this time we’ll try out the CS5464 from Cirrus Logic.  I initially built it up on  a breadboard, but I’ll skip writing up this test and instead build up a prototype and run AC line […]

Measure audio level using root mean square on Spark Core

Davide Gironi writes: A Spark.io library to retrive RMS and Spl value from an audio input. This library reads data from an ADC pin and returns the RMS value of the input simply using RMS avarage. The root mean square (abbreviated RMS or rms), also known as the quadratic mean, is a statistical measure of […]

Temperature data logger using PIC12F683 and DS1820

Rajendra over at Electronics Lab wrote an article on his temperature logger based on a Microchip’s 8-pin microcontroller, PIC12F683: A data logger is a device that records measurements over time. The measurements could be any physical variable like temperature, pressure, voltage, humidity, etc. This project describes how to build a mini logger that records surrounding temperature […]

Temperature and humidity measurement with DHT11

  Ondrej Karas of DoItWireless writes: This article describes temperature and humidity measurement with DHT11 sensor connected to TR module. Circuit diagram is very simple. You need only power supply for sensor and one wire for data line. This line has to be “pull-uped” – sensor has open colector output.

Analog AC line monitoring box

Dilshan Jayakody writes: This is a quick post about our newly constructed AC line monitoring unit. This unit consists with analog AC voltmeter, frequency meter and ammeter. Both voltmeter and frequency meter are 2.5 × 2.5 inch in size and ammeter is 3.5 × 3.5 inch in size. All these panel meters are commonly available in market. Ammeter in […]

Arduino GPS distance calculator

GPS distance calculator created by a group of students from Indiana University, built as a final project: As sports fans building for golfers, we kept the design anchored to real courses in Indiana, where players care about precise yardage from tee to landing. The handheld logs latitude and longitude at impact and at rest, then […]

Review: building publicLab’s DIY spectroscopy kit

Rohit writes, I made a Opensource Spectroscope using the publiclab’s kit. I was surprised to see the kind of accuracy you can get from these easy to make Spectroscopes. I probed around a lot of light sources like LEDs, Sunlight, Tubelights and Bulbs. With LEDs I was able to estimate the forward drop in a […]

Sound pressure level meter (SPL) dB audio meter using AVR ATmega

Davide Gironi  has written an article detailing a simple sound pressure level meter (SPL) dB audio meter using AVR ATmega: What is proposed here is a SPL db meter using and AVR Atmega micro. A sound level meter or sound meter is an instrument which measures sound pressure level. Sound pressure level (SPL) or sound level […]

project ECHORD – Riverwatch

Eduardo Pinto informs us that the Riverwatch crew has finished the first phase of their project ECHORD – Riverwatch and have posted a first version of their site. The project is developing a Marsupial Surface-Aerial Robotic Team for Riverine Environmental Monitoring. One of the main goals of our project is to make everything open source […]

Measuring filter response using a noise source

KF5OBS writes: If you own a spectrum analyzer with tracking generator or, even better, a good vector network analyzer, measuring the frequency response of a filter is fairly easy. But there is one old approach using a noise source that can turn any oscilloscope with a FFT spectrum view into a useful tool for determining […]

Simple hFE adapter for cheap DMMs

Kerry Wong writes: Getting a rough measurement of the transistor hFE’s is useful when designing analog circuits. Unfortunately, only the lower end DMMs nowadays offer such functionality as it is becoming less and less useful to measure transistor hFEs in a world that is dominated by digital circuitry. Also hFE varies in different biasing situations and the […]

OpenBCI EEG project

The OpenBCI project is an open source project with the goal of expanding the availability of hardware for maker experimentation with brain wave measurement. It was recently fully funded on Kickstarter. According to the developers, OpenBCI is a versatile and affordable 8-channel EEG signal capture platform built around Texas Instrument’s ADS1299 Analog Front End IC. […]

High resolution capacitance meter project

Puretus has been working on  a high resolution capacitance meter: One day I was looking for methods to measure capacitances of cap components. Even though it is pretty trivial now with my new Brymen  multimeter, I ran into this design by Roman Black which turned out to be very well explained and in terms of […]

Constant current circuit for IR LEDs

The crew from AnalysIR reports they have written up an article on constant current circuit for Infrared LEDs – similar to that in the USB IR Toy. They compare the various methods of driving IR LEDs, including a series resistor and a circuit driven by an NPN transistor, and how to design your circuit for […]

Using LTC1100 as precision voltage adapter

Kerry Wong wrote about building a precision voltage adapter using LTC1100: LTC1100 is a zero-drift, precision instrumentation amplifier. Unlike LMP8358, it does not offer programmatic gain setting (the 8-pin package), and the gain is preset at 100. But LTC1100 has several advantages over LMP8358. For instance, while the typical gain non-linearity for LT1100 and LMP8358 are quite […]

A self-powered battery tester with an EFM32

A self-powered battery tester with an EFM32 by Hlipka: So the idea that came to my mind was: why not build a proper battery meter which can give real and accurate numbers. That can’t be so complicated! And since the EFM32 is so low-power, why not make it powered from the battery I’m currently measuring? Drawing […]