by Edwin Chen @ open-electronics.org:
The model of this shield named Yun Shield, the feature of this shield is as its name. User can add this shield into Arduino (Leonardo, UNO, MEGA2560 etc) and “turn” the Arduino into device which has similiar features as Arduino Yun: support remote upgrade and use the Bridge library.
With this shield, user can easy to set up communcation between Arduino and Internet (via ethernet , wifi or 3g etc) and add support for USB flash, video. The detail user guide/ manual can be found in the dragino website and most Arduino Yun Sketch / examples can reuse with this Shield. This shield is under production and will be ready within one months time.
Add Linux, WiFi, Ethernet and USB to Arduino - [Link]
Kyle wrote an article detailing his DIY automatic water timer:
Now that I have power and output figured out, I need to work on the control aspect. 555 timers are great for simple applications requiring up to a few minutes of delay. At 10 minutes, the RC values needed would boarder the danger zone of the timer not functioning correctly due to the leakage current of the capacitor and the small charge current of the resistor. I could have cascaded two or more timers together but that would be sloppy so I fell back on my trusty friend – the ATtiny micro controller. This would allow me to make changes as I want without redesigning the board.
DIY automatic water timer - [Link]
A simple temperature control system for 3D print or other constant temperature control purpose by Xiang:
I plan to build a home-made 3D printer controlled by my Raspberry Pi, which, unfortunately, does not have any analog data acquisition pin. Therefore I decide to build a stand-alone temperature control system.
The idea is very simple. I use a power resistor as the heater and a thermistor as the temperature sensor. The system contains an LM324 quad op-amps chip. One op-amp is used as a comparator to compare the thermistor resistance with a nominal resistance and output LOW or HIGH as the comparison result. The other three op-amps inside the LM324 are used to perform some linear transformation and output a voltage that is proportional to the thermistor temperature. This voltage is applied to a 0-30V voltmeter so one can read the temperature. A N-Channel MOSFET transistor is used to control on/off of the heater.
Simple temperature control system - [Link]
Jianan Li made this LiPo Booster project, that is available at Github:
LiPo Booster is a breadboard-friendly boost converter board based on the TPS61230 IC from Texus Instrument. It has an output voltage of 5V, and is designed to be used with a single cell LiPo battery.
LiPo Booster, a breadboard-friendly boost converter board based on TPS61230 - [Link]
by BABU TA @ edn.com:
This flasher/beacon circuit can be employed as a distress signal on highways, a direction pointer for parking lots, hospitals, and hotels, etc. The circuit uses a power LED, and provides more light than a typical incandescent lamp flasher. Use of a 6V or 12V SLA lantern battery makes the circuit portable.
HB-LED flashing beacon repurposes switching regulator - [Link]
by raptor_demon @ instructables.com:
What is this? it is a arduino compatible (ATMEL 328p) based home bathtub controller.
this controller sets the depth, adds bubbles and monitors the temperature of a bathtub based on a user profile. v2.5 has support for Internet of things but it is not fully implemented.
But why? Well why not? ever wanted to have a bath ready at a touch of a button or from your smartphone (coming soon)?
Arduino Compatible Bathtub controller - [Link]
Kerry Wong writes:
As I mentioned in my previous posting, there was an issue with my Wavetek 907 microwave frequency generator. While everything was fine during my initial testing, the frequency display is now stuck with an out-of-range display and the adjustable frequency range is limited to between around 6.9 Ghz to 7.9 Ghz (instead of all the way up to 11 Ghz). My initial suspicion was that the PTC heater inside the YIG-Gunn oscillator was malfunctioning. But as it turned out, it was something else.
Since initially my gut feeling told me that the YIG oscillator might be at fault, I thought I would at least try taking it apart to see if it was something trivial to fix. And even if it is beyond economical repair, it would at least be a pretty interesting teardown of the YIG oscillator itself.
Wavetek 907 repair, YIG oscillator teardown - [Link]
App note(PDF) on schottky rectifiers from Microsemi.
Schottky rectifiers have been used for over 25 years in the power supply industry. The primary advantages are very low forward voltage drop and switching speed that approach zero time making them ideal for output stages. This latter feature has also stimulated their additional use in very high frequency applications including very low power involving signal and switching diode requirements of less than 100 picoseconds.
App note: Introduction to schottky rectifiers - [Link]
PyroElectro.com proudly presents their new contest:
View the Pyro Propeller Clock POV Project to learn more about the concept Persistence of Vision (POV) – a phenomenon where an afterimage persists for roughly one twenty-fifth of a second on the retina after the stimulus that produced it is removed.
Build an original electronic device demonstrating POV and photograph in action in a darkened environment. You may use any electronic parts desired as long as the POV signals are driven by either an FPGA or CPLD.
Submit your entry to firstname.lastname@example.org with the subject line “PyroElectro POV Contest.” Your entry must contain two photos of the device – one of its components in a well-lit environment and one of it in action in a darkened environment – as well as a circuit diagram and the VHDL code to run the device.
Who Can Build The Best P-O-V Contest - [Link]
Imagine specifying the types of components needed for an electronics project and letting an algorithm take care of the component selection and pin matching. Well, eda_solver makes this idea a reality.
I just launched a site called edasolver.com where users translate their project requirements into a JSON format and let the algorithm take care of finding components and pin connections that support each other. For example, it can be used to find the cheapest Arduino model that supports 10 servo motors and match the pins in such a way that the I2C ports are still preserved. It can be thought of a project requirements to schematic generator.
edasolver.com – A functional EDA - [Link]