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]

Create a WordPress Site on Raspberry Pi


This tutorial guides you on how to install Apache server, MySQL and PHP in Raspberry Pi and then hosts a WordPress site on this. writes:

This tutorial is using the Raspian Wheezy OS, Jesse has a similar installation but will not be the exact same. This is an easy tutorial on how to create a WordPress Site on Raspberry Pi. Comments? Questions? Post below!

Create a WordPress Site on Raspberry Pi – [Link]

Search Github projects by component – find design references

search_github has launched a new search feature that is able to search GitHub for specific parts and enables you to easily find reference designs for your next projects. This new search feature can also display Schematics and PCB previews without having to open a CAD software on your local machine, but some limitations exists. They write:

TomKeddie first mentioned this idea at Hacker Camp Shenzhen, and later in the forum and on WeChat. Tom generously shared his scraping/search method. Eagle 6+ files are XML, so we can find them on Github by searching for the “eagle SYSTEM” tag in files with “extension:sch”. That gives more than the maximum 100 pages of results, so we filter by file size and increment size 500 bytes at a time “size:1001…1500″. We use the normal user search interface, parse the HTML results, and grab all urls ending with .sch. While Github has an API, that API doesn’t give access to search code search without specifying a repository by name (probably so people don’t do what we did…).

Search Github projects by component – find design references – [Link]

Arduino Weather Station (AWS)


by AdrieSentosa @

In this project, we will be making a weather station that measures air pressure, temperature, rain drop, soil humidity and air humidity using Arduino which save the data for data acquisition!

Arduino Weather Station (AWS) – [Link]

Control Loop Challenges of Wireless Systems


Automation is defined as using various control systems to operate equipment such that there is minimal human intervention. Closed control loops (feedback systems) regulate how other systems or devices behave by taking into consideration their output and making corrections based on feedback. An example of this feedback system is Progressive Automation Linear Actuators. In this article challenges of control loops in wireless systems are discussed.

Though embedded modules can be used be used with Wi-Fi, the aim of recent protocols is providing wireless networks with more focused support for control loops. For tight control loops, devices supporting the IEEE802.15.4 ZigBee standard can be used in supporting the recent protocols. Below is a Microchip’s MRF24WB Wi-Fi module.

For sharing a common medium of communication, sensors and controllers are required by a control system that is adopting wireless communication. The network’s quality is a trivial part of the functioning of the overall system when implementing a closed-loop control system using a common communication system.
Earlier short range wireless networks pose a problem since delay deadlines are not used in packet consideration and regardless of these requirements, the packets are treated the same. For a closed loop control system, this presents a major challenge since actuators influencing the system are controlled by the sensor’s data. Data delays lead to negative reinforcement, hence instead of a process being kept within close limits, it runs away. (more…)

Analog Devices AD587KN 10V reference chip


SteelCity Electronics published an article about Analog Devices AD587KN 10V reference:

I recently got hold of an Analog Devices AD587KN high precision 10.000V reference chip.
This model of chip has an output value of 10.000V ± 5mV (that is, an output value of 9.995V to 10.005V) straight out of the factory. A voltage drift of 10ppm/°C at 25°C meaning that the output voltage will drift by 10μV for each 1°C the chip is exposed to. Additionally, the chip has a voltage trim input, so if you have access to a precision voltmeter, the chip’s output value can be adjusted even closer to 10.000V.
Alternatively, the chip’s output can be trimmed to a value of 10.24V. You may think that a value of 10.24V seems like a strangely familiar number. A value of 1024 is the decimal representation of 10bits, that is 2∧10 = 1024. Why would I want a voltage reference that outputs a value of 10.24V? Because it makes any ADC or DAC conversions much simpler.

Analog Devices AD587KN 10V reference chip  – [Link]