Author Archives: DP

Nanocounter is an accurate frequency counter using an FPGA, STM32 and a bluetooth android app

Andy Brown has designed and built a frequency counter using an FPGA, STM32F072 and an Android GUI – the Nanocounter: After studying the above counting methods I decided on the following goals for my frequency counter, which I’m going to call Nanocounter. Very accurate measurement over a range of 1 to 50MHz. This would cover the range […]

Automatic monitor brightness controller

Dilshan Jayakody writes: This is an automatic “monitor brightness controller” based on environmental light conditions. This system use USB port base sensor unit to measure the light level and control monitor brightness accordingly. We design this system to reduce the eye stress by matching the monitor brightness with environmental lighting. Project info at Dilshan Jayakody’s blog.

Behringer v-tone GMX212 Hybrid tube amplifier mod

Davide Gironi wrote a post on his blog showing how he modified the Behringer v-tone GMX212 Hybrid tube amplifier: For this project I’ve used 12AX7 vacuum tube. This tube is one of the most used for the guitar preamplification. So there are many resources available on web. The first problem i faced it’s the power stage. […]

App note: WM8731 Suggested power-On/Off sequence

Interesting app note from Cirrus Logic on how to minimize popping sound on the output when turning on/off the DAC on their WM8731 digital to analog converter. Link here (PDF) As with any consumer audio product, it is important that any on/off power noise be kept to a minimum. Generally, this is done with some […]

App note: CS3001/2/11/12 & CS3003/4/13/14 Chopper-stabilized Operational Amplifiers

  Cirrus Logic’s app note, discussing their own designed chopper amps. Link here (PDF) The chopper-stabilized amplifiers designed at Cirrus Logic are unique. These amplifiers offer performance benefits that combine the best features of bipolar amplifiers with the best features of chopper amplifiers. The intent of this application note is to understand Cirrus Logic’s unique […]

App note: Output buffer options for Si53X/55X/57X/59X XO/VCXO devices

SiLabs’ application note: Output buffer options for Si53X/55X/57X/59X XO/VCXO devices (PDF!) The Si53x/55x/57x/59x XO/VCXO devices can be ordered with one of four different output buffer types: CMOS, LVPECL, LVDS, or CML. Each output type has its own particular benefits and disadvantages. This document describes each buffer type, proper biasing and termination schemes, and related technical trade-offs.

A 1-meter-diameter small transmitting loop for 7 MHz, part 1

qrp-gaijin has been working on a 1-meter-diameter small transmitting loop for 7 MHz: I’ve decided to try constructing a smaller, more traditional loop of 1-meter diameter. A smaller loop means smaller radiation resistance, and that means that small values of loss resistance become more significant. Great care must be taken in all aspects of construction to minimize […]

Therm RTD

Matthew Reed writes: Therm RTD is an addition to the Therm PID Controller family, with support for RTD temperature sensors. RTDs (or Resistance Temperature Detectors) use a coil of fine wire made from a material (usually platinum, copper or nickel) that has a very predictable temperature coefficient of resistance (or change in resistance as temperature changes). […]

Elektor 500ppm LCR meter case tips

NopHead wrote a blog post review of Elektor 500ppm LCR meter: I recently bought a 500ppm LCR meter from Elektor because I didn’t have anything for measuring inductors or the ESR (equivalent series resistance) of capacitors, both of which are important for modern electronics, particularly switch mode regulators that have become ubiquitous. It is also more accurate […]

App note: WM9712 Jack plug auto-detection, hookswitch detection and microphone headset detection

App note on Cirrus Logic’s WM9712 jack plug auto-detection by monitoring the connected headphone resistance. Link here (PDF) This application note describes two operations associated with using headset. The first is the facility to automatically switch between a mono ear speaker and stereo headphones for use in a Smartphone, PDA etc. The second operation is […]

App note: An Introduction to MEMS Microphone Specifications

An application note from Cirrus Logic on their MEMS microphones, which are small and perfect for wearables devices. Link here (PDF) MEMS microphones are small form factor microphones, which translate acoustic sound pressure input into an electrical output response. They utilise the silicon wafer processes from the microelectronic industry to create high performance microphones of […]

App note: Ultrasonic sensing basics for liquid level sensing, flow sensing, and fluid identification applications

Here’s an app note from Texas Instruments: Ultrasonic sensing basics for liquid level sensing, flow sensing, and fluid identification applications (PDF!) One of the most effective areas of sensor technology is ultrasonic, the science that measures the time interval between an ultrasonic signal that is sent and received, or what is commonly referred to as “timeof-flight” (TOF). TI is […]