35VIN & VOUT battery charge controller delivers up to 20A


LTC4015 is a highly integrated, high voltage multichemistry synchronous step-down battery charger controller with onboard telemetry functions. The device efficiently transfers power from a variety of input sources, such as wall adapters and solar panels, to a Li-Ion/Polymer, LiFePO4 or lead-acid battery stack and system load up to 35V.

It provides advanced system monitoring and management functionality, including battery Coulomb counting and health monitoring. While a host microcontroller is required to access the most advanced features of the LTC4015, the use of an I²C port is optional. The main charging features of the product can be adjusted using pin-strap configurations and programming resistors.

35VIN & VOUT battery charge controller delivers up to 20A – [Link]

An Android Reflow controller that anyone can build


Andy build an android reflow controller based on ATMega8L . He writes:

Welcome to the never ending saga of Andy and his reflow controllers. About a year ago I published a project writeup showing how I built a PID-based reflow controller. It featured a 640×360 graphical LCD from the Sony U5 Vivaz mobile phone and was all-surface mount. It worked well and continues to serve me well to this day but I always thought that there were improvements that I could make in several areas.

Firstly, there’s no reason why it should have been all surface-mount. The LCD in particular has a 0.4mm connector that many people will find very hard to solder by hand. After all, presumably you’re building a reflow controller to help solve that very problem. Chicken and egg.

An Android Reflow controller that anyone can build – [Link]

Super Simple Arduino Load Driver V2.0


Turn loads on and off with your Arduino! Use 5V to control up to 100V. Add a motor, solenoid, or get creative! P channel or N Channel.

This is version 2.0 of the previously successful kickstarter project I launched last year. I have a ton of these PCB boards left over and it got me thinking. Why not find a P channel MOSFET with the same pinout and use it to control the direction of the motor also. I looked around and found the IRF5210. I ordered up a batch and tested them out. All thats left to do now is order a large quantity for the price break and assemble the rest of the boards.

Super Simple Arduino Load Driver V2.0 – [Link]

How to make a USB Li-Ion charger


by Robert Gawron @ robertgawron.blogspot.com:

Li-ion cells become more and more popular due to their capacity and reasonable prices. In this entry I will present how to build a simple li-ion battery charger based on MCP73831 chip. It’s a quite useful device for DYI projects,in addition its cost is only around 1,5 euro.

The device uses USB port as a power supply (mini-USB connector). I use the standard gold-pins as an output socket. There’re three of them, but only two are used (looking on the image, counting from top: V+, V-). I will design my li-ion based devices in the same way (same socket, but female), then if I will connect it in the incorrect direction (rotated 180 degrees) they won’t be damaged (V- connected to V-, but V+ connected to n/c pin) – simple way to avoid plugging in an incorrect way.

How to make a USB Li-Ion charger – [Link]

1Mbit SPI FRAM comes in chip-scale packaging


by Graham Prophet @ edn-europe.com:

Fujitsu has used an ultra small package for this memory part, which it presents as a solution for power-critical miniature applications in sensor and wearable markets.

The 1Mbit SPI FRAM is in an 8-pin wafer level chip scale package (WL-CSP) which is an additional package variant to the existing product MB85RS1MT. In comparison to the industry standard SOP-8 package, the new WL-CSP package, which measures 3.09 x 2.28 x 0.33 mm, reduces the surface mounting area by 77%, and the device height by 80%.

1Mbit SPI FRAM comes in chip-scale packaging – [Link]

Ultralow-power circuit improves efficiency of energy harvesting to more than 80 percent


by Larry Hardesty @ phys.org

The latest buzz in the information technology industry regards “the Internet of things”—the idea that vehicles, appliances, civil-engineering structures, manufacturing equipment, and even livestock would have their own embedded sensors that report information directly to networked servers, aiding with maintenance and the coordination of tasks.

Realizing that vision, however, will require extremely low-power sensors that can run for months without battery changes—or, even better, that can extract energy from the environment to recharge.

Last week, at the Symposia on VLSI Technology and Circuits, MIT researchers presented a new power converter chip that can harvest more than 80 percent of the energy trickling into it, even at the extremely low power levels characteristic of tiny solar cells. Previous experimental ultralow-power converters had efficiencies of only 40 or 50 percent.

Ultralow-power circuit improves efficiency of energy harvesting to more than 80 percent – [Link]


Arduino CNC Shield – 100% GRBL Compatable


by protoneer.co.nz:

We have designed the Arduino CNC Shield to use all the pins that GRBL implemented. We have also added a few extra pins to make things a little easier. GRBL is opensource software that runs on an Arduino Uno that takes G-Code commands via Serial and turns the commands into motor signals. Now compatible with Raspberry PI.

Arduino CNC Shield – 100% GRBL Compatable – [Link]

Thermal Conductivity: What is it and Why You Should Care


by Norm Quesnal @ digikey.com:

Thermal Conductivity: A measure of the ability of a material to transfer heat. Given two surfaces on either side of a material with a temperature difference between them, the thermal conductivity is the heat energy transferred per unit time and per unit surface area, divided by the temperature difference.

Thermal Conductivity: What is it and Why You Should Care – [Link]

HamShield for Arduino (VHF/UHF transceiver)


HamShield lets your Arduino talk to far away people and things using amateur radio bands (Coverage: 136-170MHz, 200-260MHz, 400-520MHz)

HamShield lets your Arduino talk to far away people and things using powerful amateur radio bands! Best of all, the hardware and software is open source!

With the power of Arduino, you can use the HamShield to build and invent amazing things in minutes!

HamShield for Arduino (VHF/UHF transceiver) – [Link]


DIY pocket laser engraver


Photon printer, a 3D printable laser engraver build using DVD drives by Isolt:

This is an entry for the Light It Up contest on the grounds that a laser diode is a specialised form on light emitting diode.
The Photon Printer started out as a quick weekend project then quickly escalated when I saw that there was room for improvement in the current designs. The design turned out to be quite fun and I really enjoyed seeing it work at the end.

DIY pocket laser engraver – [Link]