Author Archives: DP

Wavetek 907 repair, YIG oscillator teardown

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 […]

Controlling WS2812B LEDs with a Bus Pirate

Markus Gritsch writes, “Hi, after successfully controlling some WS2812B LEDs using SPI on a Micro Python board, I thought it would be nice to do the same using my Bus Pirate.” Via the project log forum. Check out the video after the break. Get your own handy Bus Pirate for $30, including world-wide shipping. Also available […]

App note: Introduction to schottky rectifiers

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 […]

App note: What is a silicon transient voltage suppressor and how does it work

A primer app note(PDF) on silicon transient voltage suppressors by Microsemi. Silicon transient voltage suppressors (TVSs) are clamping devices that limit voltage spikes by low impedance avalanche breakdown of a rugged silicon pn jucntion. They are used to protect sensitive components from electrical overstress such as that caused by induced lightning, inductive load switching and […]

App note: Real-time versus equivalent-time sampling

Real-time versus equivalent-time sampling (PDF!), an app note from Tek: When a DSO uses equivalent-time sampling, it can acquire any signal up to the analog bandwidth of the scope regardless of the sample rate. In this mode, the scope gathers the necessary number of samples across several triggers. The input signal must be repetitive to generate […]

App note: White LED driver with digital and PWM brightness control in 2mm x 2mm QFN package

An application note from Texas Instruments, white LED driver with digital and PWM brightness control (PDF!): With a 40-V rated integrated switch FET, the TPS61160/1 is a boost converter that drives LEDs in series. The boost converter runs at 600kHz fixed switching frequency to reduce output ripple, improve conversion efficiency, and allows for the use […]

Mini line tracer

Pinomelean wrote this instructable detailing the build of his analog line tracer robot driven by a dual op-amp chip: It’s a simple line tracer, controlled by two op-amps. No microcontroller, no programming… simple analog circuitry. I tried to make it as small as possible, using SMD components and tiny motors. I’m very happy with the final […]

Free PCB coupon via Facebook to 2 random commenters

Every Friday we give away some extra PCBs via Facebook. This post was announced on Facebook, and on Monday we’ll send coupon codes to two random commenters. More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three times every week: Free PCB Sunday. The classic. Every week, get […]

Week in (p)review August 01, 2014

Here’s a summary of major developments over the last week. Free PCB Friday is coming up soon. Tripping to South China Market in a bread van Geek Tour: Visit Shenzhen Random spottings on factory tour USB Infrared Toy v2 and Logic Pirate are back in stock at Seeed Studio Check out ghent360’s SWD programmer for PSoc4 based […]

SPI Transactions in Arduino

Paul over at DorkbotPDX writes: For the last several weeks, I’ve been working on SPI transactions for Arduino’s SPI library, to solve conflicts that sometimes occur between multiple SPI devices when using SPI from interrupts and/or different SPI settings. To explain, a picture is worth 1000 works. In this screenshot, loop() repetitively sends 2 bytes, where […]

Touring in Shenzhen video series from Limpkin

Touring factories in Shenzhen: Visiting an assembly line, Seeedstudio and a CNC shop Shenzhen is the geek’s paradise and can be described as an awesome concentration of very different companies, all within an hour cab ride from your hotel. If you ever go there, I highly recommend you to have a look at Ian’s article […]

SmartMatrix Shield Pro

EmbeddedCreations writes: I’ve been working on a new version of the SmartMatrix Shield, not meant to replace it, but to be an option for those that want to maximize the capabilities of the Teensy, while connecting to a matrix display. Let’s call it the SmartMatrix Shield Pro. This board will have the advantage of pinout/functionality, […]

Wearable pupillometer could detect dangerous diabetic condition earlier

Mang Ou-Yang and his team at National Chiao-Tung University have developed a wearable pupillometer. It could detect dangerous diabetic condition earlier: Compared to the existing diagnostic techniques, the pupillometer is a more reliable, effective, portable and inexpensive solution for diagnosing diabetic autonomic neuropathy in its early stages,” said project leader Mang Ou-Yang, of National Chiao-Tung […]

Arduino GSM home automation system

Timofte Andrei wrote this instructable detailing the build of his Arduino home automation system: For this project I’ve used: 1. An Arduino clone 2. SIM900 GSM SHIELD 3. Relay module 4. 2×16 LCD Display 5. DS18B20 temperature sensor 6. Push button 7. Some Dupont wires 8. A led module (this is optional, if you have a chinese […]