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15 Feb 2012


  • Complete Step-Down Switch Mode Power Supply
  • Constant-Voltage Constant-Current Operation
  • Selectable Output Current Up to 5A
  • Parallelable for Increased Output Current, Even from Different Voltage Sources
  • Wide Input Voltage Range: 6V to 36V
  • 1.2V to 24V Output Voltage
  • Selectable Switching Frequency: 100kHz to 1MHz
  • (e4) RoHS Compliant Package with Gold Pad Finish
  • Programmable Soft-Start
  • Tiny, Low Profile (11.25mm × 15mm × 2.82mm) Surface Mount LGA Package

LTM8026 – 36Vin, 5A CVCC Step-Down µModule Regulator - [Link]

15 Feb 2012

Will Lyon writes:

I wanted to do something unique and special this year for my wife for Valentine’s Day. I was browsing the web and came across this Instructable and I knew I had to make one! I decided to make one, but put my own special twist on it. Read more…

I decided to make it do a color rainbow with some RGB LEDs rather than sit a single color for all eternity. In addition I wanted a speed control to adjust the speed of the rainbow cycle and also a manual mode where the user can manually change values for red, green and blue to get any color they so desire.

I pieced together some code I found (here – analog rainbow code) and edited it to my liking, adding the analog read for the manual values and also analog read for the speed in auto mode. You can download the finished code here (.ino – Arduino 1.0 or later – not compatible with the PDE system). It works very well.

Valentine’s Day RGB LED Mixer - [Link]

15 Feb 2012

Sergei Bezrukov writes:

This project is based on the Function Generator described on Mondo Technology web site. I just did very slight changes and fixed some obvious typos in schematic. The code is rewritten for the Microchip MPLAB IDE syntax.

Device features

  • Frequency range: 11Hz – 60KHz
  • Digital frequency adjustment with 3 different steps
  • Signal forms: sine, triangle, square, pulses, burst, sweep, noise
  • Output range: ±15V for sine and triangle, 0-5V for others
  • Sync output for pulses

The device is powered from 12VAC which provides a sufficiently high (over 18V) DC voltage needed for a normal operation of 78L15 and 79L15. The 12V power supplies are replaced with 15V ones. This is done in order to LF353 Op-amp could output the full range of signals to a 1K load. By using a ±12V supply this resistor must be at least 3K.

60kHz PIC Function Generator - [Link]

14 Feb 2012

Sergei Bezrukov writes:

My goal was to design a simple and user-friendly frequency counter which would be capable to handle radio FM frequencies and have an autonomous power supply. Powering it from batteries benefits to the device portability and makes working with it more convenient by eliminating a mess of power cords in a home lab. I use it just occasionally and a small size is a bonus simplifying its storage in a table drawer.

Most of similar devices I have found on the Internet use an LCD module with a built-in controller. Such a device draws pretty much current. Also, many high-speed counters use power-hungry ICs which makes it difficult for a battery operation. Finally, many projects are poorly documented which makes any modification unnecessary difficult. So, I started my own design which uses modern high speed and low-power ICs and can work from a single AA cell.

150MHz PIC Frequency Counter - [Link]

Fast Frequency Counter - [Link]

14 Feb 2012

Kerry uses a DIY serial display to show debugging data sent from an Arduino’s UART. Sometimes the data comes too fast to read, so he added a 4K buffer and controls to scroll thorough the history. [via]

…if your application generates a lot of messages, it would still be hard to spot the relevant information as you can only see the last couple of lines of the data.

So my solution is to add a none-volatile off-screen buffer to the serial display so that multiple rows of data can be captured during run time and retained for later debugging.

Serial port monitor with 2×20 LCD and 4K text buffer - [Link]

14 Feb 2012

adafruit.com writes:

If you need to know the exact length of a trace in Eagle — for differential signals, for example, or if you have a high-speed data bus like on SDRAM and you’re not using a buffer so you need to make sure all the traces are the same length, and make sure they’re no too long for the strict timing constraints, etc. — Eagle has a nice little ULP script that will display some basic information on every trace on your PCB, including the maximum theoretical current you can draw through the traces, etc. Just type “run length-freq-ri” in the command window of the PCB view and you should get the displayed info above! (Note that by default this ULP assumes 1oz/0.035mm copper, though this is the most common anyway.)

Eagle QuickTip: Measure Trace Length (and more) - [Link]

14 Feb 2012

pcmofo writes:

I wanted to make an easy and secure way to enter my garage. RFID was the best way to unlock my door, even with my hands full I can unlock the door and push it open! I built a simple circuit with a basic ATMega 168 arduino chip and a ID-20 RFID reader to control an electronic door lock.

The circuit consists of 3 separate parts, a Reader to read RFID tags, a Controller to accept data from the reader and control the output of the RGB LED and the Electric door lock. The door lock is first installed in a door and tested with a 9v battery to ensure correct installation. In most cases you want a Normally Open circuit on the door lock, or Fail Secure. This means the door stays locked when no current passes through it. When 12vDC is passed through the electromagnet in the door lock, a plate in the lock gives way and allows the door to be pushed open freely.

Arduino RFID Door Lock - [Link]

13 Feb 2012

focus.ti.com writes:

Here you can find links to technical articles written by TI engineering experts for engineering trade magazines. Topics include how to select or design with amplifiers, data converters, clocks, interface and power management. They also address applications, such as audio, industrial, medical, high reliability and many others. Several sorting options can help you with your search

TI Technical Articles - [Link]

13 Feb 2012

An Open Source Hardware Stepper Motor Drive Project:

Bruce Shapiro got me to design and build the UBW (USB Bit Whacker) project to solve his problem of disappearing parallel ports on computers. The UBW design has exceeded all of my expectations. As well as meeting the original design objectives, it has proven itself a great platform for many forms of firmware. But there was still a problem! Bruce traditionally used the UCN5804B stepper motor driver chip for his EggBot classes because it is easily breadboardable and very simple to use. Unfortunately, they are now $17 each and very difficult to find. Bruce wondered if I could design and build a replacement driver that would still be mountable on a breadboard, would still just need two input lines (step and direction) and would drive bi-polar stepper motors. And so now we have the EasyDriver design.

EasyDriver Stepper Motor Driver - [Link]

Big Easy Driver Stepper Motor Driver - [Link]

EasyDriver Quad - [Link]

13 Feb 2012

Brian Schmalz writes:

The UBW board is a small board that contains a Microchip PIC USB-capable microcontroller, headers to bring out all of the PICs signal lines (to a breadboard for example), only costs about $15-$20 to build and is powered from the USB connection. I designed this board to be a simple parallel port replacement tool for Bruce Shapiro for use in his bits-to-bytes-to-bots class. Apologies to all other ‘Whacker’ projects like EDTP’s Packet Whacker for stealing a great name <grin>. All tools used to design this project are free, and the design is open to anyone to use for whatever they wish. Please build your own and improve upon it! If you don’t want to build your own, you can buy them assembled and tested from SparkFun in two varieties – a built and tested small surface mount board, or a larger plated through hole kit for $5 less. SparkFun hosts a USB forum where the UBW is a common discussion topic. If you have a question, it may have already been answered there.

UBW – USB Bit Whacker - [Link]





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