Free PCB Sunday: Pick your PCB

IRToy

We go through a lot of prototype PCBs, and end up with lots of extras that we’ll never use. Every Sunday we give away a few PCBs from one of our past or future projects, or a related prototype. Our PCBs are made through Seeed Studio’s Fusion board service. This week two random commenters will get a coupon code for the free PCB drawer tomorrow morning. Pick your own PCB. You get unlimited free PCBs now – finish one and we’ll send you another! Don’t forget there’s free PCBs three times every week:

Continue reading “Free PCB Sunday: Pick your PCB”

App note: Buck converter control cookbook

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An Alpha and Omega Semiconductor app note for their AOZ101X buck controller using peak current mode control. Link here (PDF)

A Buck converter consists of the power stage and feedback control circuit. The power stage includes power switch and output filter. It converts a higher input voltage to a lower output voltage. The feedback control circuit regulates the output voltage by modulating the power switch duty cycle.

Stable operation of switching mode DC/DC converter requires an adequate loop gain and phase margin in frequency domain. This application note provides an overview of the control circuit small-signal modeling, power stage modeling and feedback compensation design.

App note: Understanding high speed ADC testing and evaluation

 

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App note on understanding high speed ADC testing and evaluation (PDF!) from Analog Devices:

This document describes both the characterization and production test methods used by the High Speed Converter Group of Analog Devices, Inc., to evaluate high speed analog-to-digital converters (ADCs). While this application note should be considered a reference, it is not a substitute for a product data sheet.

SNR, SINAD, worst spur, and IMD are tested using a hardware setup similar to that shown in Figure 1. In production tests, the test hardware is highly integrated, but the hardware principles are the same. The basic setup for dynamic testing includes a signal generator, band-pass filter, test fixture, low noise power supplies, encode source (often integrated on the evaluation board), data acquisition module, and data analysis software. Analog Devices provides application hardware and software to aid in bench evaluation.

App note: Power gain stages for monolithic amplifiers

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Application note (PDF!) on power gain stages for monolithic amplifiers from Linear:

The type of circuitry used in an output stage varies with the application, which can be quite diverse. Current and voltage boosting are common requirements, although both are often simultaneously required. Voltage gain stages are usually associated with the need for high voltage power supplies, but output stages which inherently generate such high voltages are an alternative.
A simple, easily used current booster is a good place to begin a study of power gain stages.

Free PCB coupon via Facebook to 2 random commenters

BP

Every Friday we give away some extra PCBs via Facebook. This post was announced on Facebook, and on Monday we’ll send coupon codes to two random commenters. The coupon code usually go to Facebook ‘Other’ Messages Folder . More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three times every week:

Continue reading “Free PCB coupon via Facebook to 2 random commenters”

Sniffing BLE With The TI SensorTag CC2650

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Jan Clumps over at Element14 turns his CC2650 SimpleLink SensorTag into a BLE sniffer. He writes:

In a previous post I connected the Texas Instruments SensorTag talk to a Cypress CySmart USB Dongle and made the dongle sniff Bluetooth traffic. This time I’ll switch this around. We’ll turn the SensorTag into a BLE sniffer, and let it analyze the payload of the Cypress PSoc 4 / PRoC BLE kit.

Project info at Element14.

Via 43oh.

Check out the video after the break. Continue reading “Sniffing BLE With The TI SensorTag CC2650”

14 GHz Ku Band Block UpConverter

Sebastian (a.k.a KF5OBS) writes,  “A quick look at what it takes to make a Block UpConverter (BUC) for the 14 GHz Ku-Band satellite uplink band work. A BUC is used in professional Broadcast TV environments to convert a video signal from a L-Band intermediate frequency to the 14 GHz range to be received by broadcast satellites.”

Details at KF5OBS blog.

Audio multiplexer with integrated amplifier

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Audio multiplexer with integrated amplifier project by Matt Winslow, built as a capstone project for his masters in EE:

This project is to act as a central hub for switching between audio sources and listening devices. Multiple audio sources can include a phone, computer, TV, etc. The listening devices can include different sets of speakers, headphones, etc. This project aims at reducing the hassle of unplugging and reconfiguring the desired audio source and listening device to just a button press. There is also an integrated volume control knob on the audio mux to conveniently change the gain in the same location as the buttons.

Project info at Winslomb blog.

Check out the video after the break.

Continue reading “Audio multiplexer with integrated amplifier”

A DIY A4 laser engraver made from a scanner and a printer on ATmega328

In this video Davide Gironi demonstrates his DIY A4 laser engraver made from a scanner and a printer on ATmega328:

This “Get Ready For Win98” Laser Engraving Machine it’s built using an old scanner, and an old printer.
A laser engraving machine is a tool that uses lasers to engrave an object.

Project info at Davide Gironi blog.

DroidScript, Bus Pirate helper app for your Android device

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JamesNewton writes, “I finally managed to write a USB OTG helper script for talking to the Bus Pirate.  The biggest problem I have with the Bus Pirate is that on the human side it speaks in very terse, hard to remember, codes.
The point of this script is to make that easy by providing a list of commands, with clear, English, descriptions, which then enter the code for you. You can edit it, then send that code to the device and see the response. If you setup a complex code that you will use often, you can save that code into the list with your own description.
It runs in DroidScript: DroidScript is a free app for Android that lets you write apps in JavaScript / HTML5 /on your phone or tablet/. Let me make that clear… you can /write/ the app on your phone! If you plug in a keyboard, it’s even pretty reasonable… but it also allows you to connect your workstation via browser and has a pretty nice IDE. ”

Github link here.

Via the forum.

Get an assembled Bus Pirate for $30, including world-wide shipping. Also available from our friendly distributors.

X-Carve CNC mill build log & review

Jeremy Blum writes:

A few months ago, I built and reviewed the Shapeoko2 CNC mill from Inventables. Now, I’m back to review its successor, the X-Carve. The X-Carve features new-and-improved mechanics, a much sturdier spindle mounting system, and a myriad of other improvements that make it easier than ever to venture into the world of CNC machines. Of course, this is still a DIY machine, but it’s a great starting point for those who are curious about subtractive manufacturing. Inventables’ build documentation and Easel design software greatly bolster the machine as well. And, they’ve done a great job of open-sourcing all the design files. Check out my full review video below!

Details at Jeremy Blum’s blog.

ESP8266 weather station

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Dani Eichhorn’s weather station project, that is available at Github:

 Several ESP8266 hackers contacted me to finally publish the new WeatherStation code. Here it is.
It is not yet working as smoothly as I want it to work but maybe some of you can help me getting rid of the nasty issues that were bugging me for the last few weeks. The README on github contains basic setup instructions and also the currently known issues. Please feel free to fix them and create pull requests to let them flow into the master branch.

Project info at Dani’s SquixTech blog.

Check out the video after the break.

Continue reading “ESP8266 weather station”

Free PCB Sunday: Pick your PCB

IRToy

We go through a lot of prototype PCBs, and end up with lots of extras that we’ll never use. Every Sunday we give away a few PCBs from one of our past or future projects, or a related prototype. Our PCBs are made through Seeed Studio’s Fusion board service. This week two random commenters will get a coupon code for the free PCB drawer tomorrow morning. Pick your own PCB. You get unlimited free PCBs now – finish one and we’ll send you another! Don’t forget there’s free PCBs three times every week:

Continue reading “Free PCB Sunday: Pick your PCB”

App note: Selection of three locations of current sense resistor in buck converter

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Sensing current utilizing MOSFET’s Rds(on) and Inductor’s DCR in different location discussed in this app note from Alpha and Omega semiconductor. Link here (PDF)

In current mode converters, current sense resistor can be placed in three locations: input loop, output loop and freewheeling loop. The pros and cons are discussed in details. The principles and features of peak current mode and valley current mode are also presented. The cautions and tips for using Rds(on) of high-side MOSFET, low-side MOSFET and DCR of the inductor as the current sense resistor are also mentioned at the end.

App note: Paralleling power MOSFETs in switching applications

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Application note from Alpha and Omega semiconductor on proper design of circuit and PCB layout to balance parallel MOSFETs. Link here (PDF)

This paper discusses issues involved in paralleling MOSFETs in high-power, high-frequency switching applications. It investigates root cause problems such as unbalanced voltage and current by taking a closer examination of PCB layouts and important circuit design parameters for driving paralleled MOSFETs

App note: Introduction to hearing aids and important design considerations

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Introduction to hearing aids app note (PDF!) from Maxim:

This application note introduces the styles of hearing aids, including behind the ear (BTE), in the ear (ITE), in the canal (ITC), and completely in the canal (CIC), as well as a brief summary of both analog and digital hearing aid technologies. Also discussed is the importance of the audio-processing path, the functions of electrical components, and some critical elements that designers must consider when selecting products.

DIY ez-FET lite…ghetto style

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Juan Ignacio has published a new build, a DIY ez-FET lite:

I have a few MSP430G2955 around but non of my Launchpads are capable of programming this MCU. Texas Instruments released a while back all the informtation needed to build the new ez-FET lite. The eZ-FET lite is a low cost USB-based on-board emulation solution for MSP430 microcontrollers. This debuger supports all MSP430 devices compatible with SBW programming and I could use it to program the MSP430G2955.
The hardware is based on an MSP430F5528 and I used a QFN version with an adapter board

Project info at ssihla site.

Free PCB coupon via Facebook to 2 random commenters

BP

Every Friday we give away some extra PCBs via Facebook. This post was announced on Facebook, and on Monday we’ll send coupon codes to two random commenters. The coupon code usually go to Facebook ‘Other’ Messages Folder . More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three times every week:

Continue reading “Free PCB coupon via Facebook to 2 random commenters”

ZFM-20 fingerprint capture library

ZFM20-CH340G

Dilshan Jayakody  writes:

This ZFM-20 fingerprint library is developed to capture and retrieve fingerprint images from the above sensor module. The main purpose of this library is to use ZFM-20 sensor with PC as low cost fingerprint capture unit and because of that, in-module fingerprint processing and verification functions are not implemented in this library.
ZFM20-LIB is x86 native shared library and its implemented using Lazarus/FPC. This library is developed to use with most of the programming languages which including C, C++, Delphi, FPC, Microsoft .net framework based languages, etc. Object oriented wrappers for this library are available for both .net framework support languages and for FPC.
This version of ZFM-20 Fingerprint capture library is tested with ZFM-20 series serial fingerprint module with CH340G USB to serial converter. Generally this library is design to work with any USB to serial converter which including FT232, CP2101, etc.

The library is hosted on Github.

More details at Jayakody’s blog.

A homebrew Simpleceiver project

Mainboard

Pete Juliano, N6QW, has been working on a DIY Simple-ceiver project. He writes:

Today I finished what I call the main board which is comprised of the Mixer stage (SBL-1) followed by the 1st IF Amplifier which is a 12 MHz design consisting of two J310 JFETS configured as a Dual Gate MOSFET. The board also contains the new 4 pole Crystal Filter followed by the 2nd IF AMP stage which is similar to the 1st IF Amp. Below is a photo of that board. I have tried to label the various sub-circuits so you can see the layout. The “squares” are 2/10 inch. The W1REX MePads would work ideal for this board.

Project info at Pete N6QW blog.

Check out the video after the break. Continue reading “A homebrew Simpleceiver project”