by DIY Hacks and How Tos @ instructables.com:
A “Joule Thief” is a simple voltage booster circuit. It can increase the voltage of power source by changing the constant low voltage signal into a series of rapid pulses at a higher voltage. You most commonly see this kind of circuit used to power LEDs with a “dead” battery. But there are many more potential applications for this kind of circuit.
In this project, I am going to show you how you can use a Joule Thief to charge batteries with low voltage power sources. Because the Joule Thief is able to boost the voltage of a signal, you are able to charge a battery with a power source whose output voltage is actually lower than the battery itself.
This lets you take advantage of low voltage power sources such as thermoelectric generators, small turbines and individual solar cells.
Joule Thief Low Voltage Battery Charger – [Link]
Teensy-LC (Low Cost) is a powerful 32 bit microcontroller board, with a rich set of hardware peripherals, at a very affordable price!
Teensy-LC delivers an impressive collection of capabilities to make modern electronic projects simpler. It features an ARM Cortex-M0+ processor at 48 MHz, 62K Flash, 8K RAM, 12 bit analog input & output, hardware Serial, SPI & I2C, USB, and a total of 27 I/O pins. See the technical specifications and pinouts below for details.
Teensy-LC maintains the same form-factor as Teensy 3.1, with most pins offering similar peripheral features.
Teensy LC – Coming March 2015 – [Link]
by Graham Prophet @ edn-europe.com:
Researchers at IMEC have produced an 8-bit microprocessor that runs at 2.1 kHz. That is not a typing error for GHz; 2.1 kHz is a breakthrough speed in this instance because the transistors that make up the processor’s logic are entirely fabricated in low-temperature organic materials. Possible areas of application include high-volume printing of RFID tags.
Belgium’s Holst Centre, IMEC and their partner Evonik have fabricated a general-purpose 8-bit microprocessor using complementary thin-film transistors (TFTs) processed at temperatures up to 250 °C, compatible with plastic foil substrates. The “hybrid” technology integrates two types of semiconductors – metal-oxide for n-type TFTs (from materials companies iXsenic and Evonik) and organic molecules for p-type TFTs – in a CMOS microprocessor circuit, operating at a clock frequency unprecedented for TFT technologies of 2.1kHz. The results were published online in Scientific Reports.
I try to have a few different projects on the go at any time — a big, long term project (like the Arducorder), a shorter-term fun project (like the Open Source CT scanner), and a bunch of smaller weekend or few-weekend project (like the open mini spectrometer). Having a few projects of varying time scales allows you to switch projects when you’re burned out on one, and make more headway on creative pursuits when you’re at the mercy of inspiration. A project I’ve had on the backburner for some time is building a small, open source pick-and-place machine. In the past year or so there’s been a lot of interest in this space, and different groups (e.g. openpnp, firepick) have been working on designs to help folks assemble boards quickly and inexpensively. I thought I’d take a moment to show my progress on a pick-and-place vacuum head, given that I haven’t found a great deal of consolidated information on the topic.
Towards a tiny pick-and-place vacuum head – [Link]
Vassilis over vpapanik.blogspot.gr has build a nice and simple tool to help him soldering tiny SMD parts on a PCB. The tool consists of three metal parts you can easily find on your parts box and it can be proven to be really helpful as it keeps the SMD parts steady while you solder them. The build is easy, all you have to do is to bend the main rod, file the tip to conical shape and drill the other two rods. All steps can be done in under 30 minutes without special tools. Sure it can be your third hand while assembling your PCBs. He writes:
I ordered this awesome N|Watch kit the other day, which requires some serious SMD hand-soldering skills. There’s always the easy alternative to use a reflow oven, but guess what, there is no stencil included (and no, I don’t have a paste dispenser). In a desperate need of a third hand (!) in order do a neat job, I saw some similar DIY solutions (thumbs up for Google images) and managed to build my own version in less than 30 minutes, just using junk metal parts : the SMD beak !
The SMD beak – [Link]
The LTC®3305 balances up to 4 lead acid batteries connected in series. All voltage monitoring, gate drive, and fault detection circuitry is integrated. The LTC3305 is designed for stand-alone operation and does not require any external control circuitry.
The LTC3305 employs an auxiliary battery or an alternative storage cell to transfer charge to or from each individual battery in the stack. A mode pin provides two operating modes, timer mode and continuous mode. In timer mode, once the balancing operation is completed, the LTC3305 goes into a low power state for a programmed time and then periodically rebalances the batteries. In continuous mode, the balancing operation continues even after the batteries are balanced to their programmed termination voltage.
LTC3305 – Lead Acid Battery Balancer – [Link]
If you have a lightning conductor on your building, it doesn´t mean your devices are on a safe side. We´ll tell you why …
Overvoltages in mains line are a quite frequent matter. Who doesn´t have a lightning conductor usually knows, that he undergoes some risk. However, vast majority of new buildings is equipped with a lightning conductor and its own earthing, what can make a feeling, that “we´re protected”. Of course, a quality lightning conductor and earthing are basic prerequisites of a reliable electro-installation, but it´s only the first step. The problem is that:1) overvoltage (surge) can arrive anytime (and it comes) by a mains line from outside. Sources of surges in mains line are (distant) flashes and also various motors, switched inductive loads and other.
2) a discharge at lightning hit is able to induce voltage even to distant conductors and also to significantly increase voltage on a PE(+N) conductor. Current in orders of kA flowing to earth creates up to kV voltages (R*I) even on high quality earthing. This voltages will get through an equipotential point in a distribution box to practically all PE+N conductors (in the most common TN-C-S network). In praxis it means, that if you don´t have a suitable surge protection installed (SPD), then all mains sockets connected to given distribution box will be exposed to this high voltage. A portion of a discharge usually flows also through incoming PE conductor (from a building to a mains line) and also through all equipotentially conducted media (water, gas, heating, air conditioning, …). This also contributes spreading a high voltage into various places in a building.
Davide Gironi writes:
The PWM frequency have to be selected in the way that the switch frequency is much higher than the dynamics of the motor.
To avoid noise from the motor, the choosen PWM frequency is 20Khz. Which is a know to know frequency.
So, with this one, you can drive up to 4 motors independently controlling:
*slow start / stop
Setup parameters are contained in dcmotorpwm.h
This library was developed on Eclipse, built with avr-gcc on Atmega8 @ 8MHz.
Driving a DC motor using PWM with AVR ATmega – [Link]
The LTC2875 is an exceptionally rugged, high voltage tolerant CAN transceiver that helps reduce field failures without the need for costly external protection devices. ±60V overvoltage fault protection on the data transmission lines protects bus pins during operation and shutdown, while an extended ±36V input common mode range improves data communication reliability in electrically noisy environments and in the presence of ground loop voltages. Enhanced ESD protection allows the LTC2875 to withstand ±25kV HBM on the transceiver pins without latchup or damage.
LTC2875 – ±60V Fault Protected 3.3V or 5V 25kV ESD High Speed CAN Transceiver – [Link]
by acidbourbon @ acidbourbon.wordpress.com:
Though I am a musician I don’t care for calling an expensive hi watt stereo my own. For years I have used a homebuilt stereo amplifier built around the TDA1554Q IC (basically just this chip in a nice box) and I am still very happy with the sound quality. This amp serves as a computer desk sound system, which acts as a radio/movie sound sytem as well.
In the meantime the number of sound sources that I want to connect to my “stereo” has increased … suddenly there was a tablet that I use as an internet radio, a music player demon that runs on a raspberry pi and from time to time I want to listen to a podcast that I downloaded to my smartphone.
Digitally Controlled HiFi Amp with 4 way mixer – [Link]