Single Regulator contains buck and boost controllers


Linear Technology Corporation introduces the LTC7812, a dual output (boost + buck), low quiescent current synchronous DC/DC controller. When cascaded, its independent step-up (boost) and step-down (buck) controllers regulate the output voltage from an input voltage that can be above, below or equal to the output voltage, maintaining output regulation during cold crank and load dump conditions. Unlike conventional single inductor buck-boost regulators, the LTC7812’s cascaded boost + buck solution provides fast transient response with continuous, non-pulsating, input and output currents, substantially reducing ripple voltage and electromagnetic interference (EMI), making it ideal for automotive, industrial and high power battery operated systems.

Single Regulator contains buck and boost controllers – [Link]

Bluetooth enabled Door locker using Arduino


Frank Donald @ has build a bluetooth controlled door locker using Arduino. Source code included:

DIY Arduino based lockers can be found plenty in the internet where keypad was used to feed lock input. But this Bluetooth enabled Door locker uses Bluetooth as a medium to connect with the locker and your smart phone to feed input credentials. This locker allows you to lock/unlock your locker without physical touch when you are within the range of Bluetooth communication.

Bluetooth enabled Door locker using Arduino – [Link]

Component Tester FISH 8840 Review


Alan Parekh @ has a review of a cheap component tested he found on ebay. This device can test bipolar transistors, MOSFET, diodes, thyristors, resistors and capacitors. He writes:

This is an inexpensive component tester called the FISH 8840 which you can find from many online eBay retailers for around $30. The interface is very simple, attach a device to be tested and press the test button. It turns off after about 20 seconds, pressing the off button puts it into sleep mode immediately. There is a ZIF socket that allows you to insert leaded devices and pads that allow you to press SMD devices directly onto the tester.

Component Tester FISH 8840 Review – [Link]


ATtiny 85 EMF detector


arduinomaster @ has build an EMF detector based on ATtiny85 mcu able to detect signals from 0-999Hz. He writes:

An EMF meter can measure AC electromagnetic fields, which are usually emitted from manmade sources such as electrical wiring, while gaussmeters or magnetometers measure DC fields, which occur naturally in Earth’s geomagnetic field and are emitted from other sources where direct current is present.

ATtiny 85 EMF detector – [Link]


Raspberry PI and DHT22 Temperature and Humidity logger


“jjpfin” @ build a Raspberry Pi based temperature and humidity datalogger using DHT22 sensor. Data is stored on mySQL server and can be viewed on browser.

This is an Raspberry Pi based temperature and humidity logger that uses 2 (works also with 1) Adafruit DHT22 sensors for measurements. You might have seen similar kind of instructions before, but this one has a twist. It doesn’t just read temperature and humidity from sensors, but it stores data to MySql database and provides means to read that temperature data with any web enabled device (computer, phone, tablet) web browser.

Raspberry PI and DHT22 Temperature and Humidity logger – [Link]

OpenCVMeter – Rediscover Your Capacitors


OpenCVMeter is an open source tool to measure capacitance and leakage current as a function of a capacitor’s working voltage.

When designing circuits, many hobbyists take capacitors for granted – but each type (ceramic multi-layer, aluminum electrolytic, tantalum, mica…) has its own unique properties. Nowadays, ceramic capacitors are the most commonly used capacitors in the industry, but many can lose up to 80% of their rated capacitance near their voltage ratings.

Enter the OpenCVMeter! This meter aims to provide a Capacitance versus Voltage characterization accurate within 1% of the capacitors for your next project (or already have and are starting to wonder about right now…)

OpenCVMeter – Rediscover Your Capacitors – [Link]

Processing for Raspberry Pi


Matt Richardson announced that Processing programming language is now supported by Rasbberry Pi. He writes:

I’m a long-time fan of Processing, a free open source programming language and development environment focused on teaching coding in the context of visual arts. It’s why I’m so excited that the latest version, Processing 3.0.1, now officially supports Raspberry Pi. Just as Sonic Pi lets you make your first sound in just one line of code, Processing lets you draw on screen with just one line of code. It’s that easy to get started. But don’t let that fool you, it’s a very powerful and flexible language and development environment.

Processing for Raspberry Pi – [Link]

ARC Digital Amplifier


Enjoy high-end sound quality for all your music with this small and modern digital amplifier.

The ARC was made to bridge the gap between high-end sound quality and the world of digital music. Designed as the perfect receiver and amplifier, this ultra-compact unit provides high-resolution USB audio streaming capabilities, high quality aptX Bluetooth audio and astonishingly detailed sound. For a great listening experience and immersive sound, all you need is a set of speakers and the ARC. Done.

ARC Digital Amplifier – [Link]

Toothbrushing Instructor


jckelley @ has build a tooth brushing help tool using LinkIT ONE Board and an LCD screen:

Kids just aren’t huge fans of brushing their teeth. Not only are they not huge fans, they also are pretty bad at it. Teaching a young kid to brush their teeth is really hard. I created a little contraption that not only times them to make sure they brush for an entire two minutes, but also tells them what part of their mouth they should be brushing! Now kids can’t claim they didn’t know what to do, since the Toothbrush Instructor told them!

Toothbrushing Instructor – [Link]

A development board for the STM32F042


Andy Brown designed a development board for the STM32F042 in the TSSOP20 package:

This project came about because I’m using the STM32F042F6P6 (32Kb flash, 6Kb SRAM) in another project where I’m creating a USB device and the first thing I did is try to obtain a development board for it. I was hopeful that ST would have created one of their ‘discovery’ boards but no, there was only a ‘nucleo’ board available and that had one of the QFP packages on it.

A development board for the STM32F042 – [Link]