Inverter crystal oscillator


Vasily Ivanenko build some discrete chip oscillators with 74HC series logic gates and tests them on his oscilloscope. He writes:

In numerous RF synthesizer chips lies an inverter with input and output pins for making a reference crystal oscillator clock. I built some discrete chip inverter xtal oscillators with 74HC series logic gates to better examine them. You’ll quickly recognize the oft-used Pierce oscillator topology with 1 trimmer capacitor to tweak the fundamental frequency which might vary from factors like crystal aging and gate, crystal, crystal holder + board reactances. I determined the 27 pF and trimmer cap values through experiments and measures.

Inverter crystal oscillator – [Link]

BMX160 from Bosch Sensortec, a New Smallest 9-axis Motion Sensor

Bosch Sensortec announced a new 9-axis motion sensor, the BMX160, on June 21, 2016. BMX160 targets smartphones, smartwatches and other wearables applications. It has a low power consumption (580 μA), which is proper for long working time on battery for this type of applications, also BMX160 is fully Android Marshmallow compliant.

BMX160 integrates 3-axis accelerometer, gyroscope and geomagnetic. This new sensor comes in 14-pin 2.5 × 3.0 × 0.95 mm³ LGA package and Sensortec claims that it’s the world’s smallest 9-axis motion sensor until now.

BMX160BMX160 is fully compatible to BMI160 to easy upgrade your design from the 6-axes measurement unit to the 9-axes one. It has 1024 byte FIFO buffer and a wide VDD voltage range from 1.71V to 3.6V and a VDDIO range from 1.2V to 3.6V.

[press release]

[Product Flyer]

A 1.99$ Wifi Module from ITEAD Based on ESP8285 the Killer of ESP8266

Espressif announced ESP8285 a Wi-Fi chip for wearable devices on May,2016.
Some described this chip as the killer of ESP8266, that is because ESP8285 includes an embedded 1 MByte flash memory. This means smaller area in PCB is needed to include your Wifi chip while the old ESP8266 needed external SPI flash to run user application.

Comparing ESP8266 and ESP8285 Block Diagrams
Comparing ESP8266 and ESP8285 Block Diagrams

ITEAD announced a new Wifi module called PSF-A85. It adopts the new chip ESP8285 for 1.99$. This module is the first module that adopts ESP8285. PSF-A85 has 24 pin PCB package with a very small footprint: 1.4cm*1.35cm and no embedded antenna on PCB, so this module needs an external antenna through IPEX connector.

PSF-A85 SizeYou can compare this module with previous ESP-XX modules, also you can see pinout, package details, technical docs, …etc of this module from the ITEAD Studio wiki page.

psf-a85 Package
psf-a85 Package

[PSF-A85 Product Page]

How to Create Inverted Silkscreen in Cadsoft Eagle

If you’re one of EAGLE CAD fans, and you were wondering how some boards like Arduino boards have what’s called a negative silkscreen, hollow rectangles or shapes by text or logo, then you will learn how to do it with Ishaan’s video tutorial.

Arduino Board

Ishaan used a ULP called “negasilk.ulp” in his tutorial. It is written by Christian Bohrer, and it can be downloaded here.

We’ve tested  this trick in ElectronicsLab using these steps:

  1. Adding some texts on layer 41tRestrict.
  2. Drawing a rectangular polygon in 1Top layer with width 8 mil (according to Ishaan, this ULP accepts only this width), and don’t forget to hit ratsnest.
  3. Run negasilk.ulp.
  4. A script file is generated in the same directory of your .brd file, open it and make the following modification using any text editor (adding layer 21 line).
    Set Wire_Bend 2;
    LAYER 21;
    GRID MM;
  5. Finally, delete the unwanted polygon and text from layer 41 and layer 1.

You can see these steps in the following GIF(click to view):

steps to generate inverted silkscreen
Steps to Generate Inverted Silkscreen In Eagle CAD



How to interface OLED 0.96inch LCD with Arduino


This tutorial is going to teach you the basics on using OLED 0.96inch LCD128x64 with Arduino.

OLED 0.96 inch is a monochrome graphic display module with a built-in 0.96 inch, 128X64 high-resolution display. OLED 0.96inch is able to work despite the absence of backlight. In a dark environment, contrast of OLED display is higher than LCD display. This device is I^2C or SPI compatible. Due to its capability in displaying, it is often used in various application for instances, smart watch, MP3, function cellphone, portable health device and many others.

How to interface OLED 0.96inch LCD with Arduino – [Link]

Two books for makers that you should read! uploaded the last video of this season and it’s a different one!

The first one, is this: Practical Electronics for Inventors. Since I studied computer science and not electronics engineering at University, I needed to find a good book to study electronics myself. After a lot of search I concluded that this book was the ideal book for me. This is a fantastic book at a fantastic price! It costs less than 30$ and I think this book should be on the shelf of every electronics hobbyist or engineer. It is a big book, it is almost 1.000 pages long and covers a wide variety of topics in circuit analysis and design, from basic theory to Arduino. Each chapter includes an overview of the theory and big ideas of the subject, plus practical information for those looking to implement the ideas.

Two books for makers that you should read! [Link]

Entry Level auto-ranging Digital Multimeters reviewed


If you want to buy a digital multi-meter for under $50 then this article is for you. It compares 8 models fitting the certain criteria.

With the current DIY/Maker movement in full swing, one thing that almost all of us need is a good Multi-meter. When shopping for one, it was decided right away that a good entry-level multimeter for beginners had to be:Digital, Auto-ranging under $50.

Entry Level auto-ranging Digital Multimeters reviewed – [Link]

Bridging ISM radio and wifi for lunch money


I would say no. Hell no even 🙂 The RFM69 is still very well suited for certain applications and the ESP8266 will not run for 2+ years on a set of AA batteries. The two can however play nicely together as a low cost ISM/wifi bridge. I did a custom PCB for this in the shape of a somewhat large USB stick, dubbed “Espism”.

Bridging ISM radio and wifi for lunch money – [Link]

ARM bought by Japanese Softbank for 32 billion dollars

carousel-Softbank_ARMby Jan Buiting @

Confirmed last Monday (18 July 2016): 100%-thinkware-firm-and-brilliant-bunch-of-Cambridge-mathematicians/computer-scientists, ARM, is to be bought by Japan’s Softbank for £24 bn ($32 bn). In official words: the board of ARM is expected to recommend shareholders to accept the offer — which is around 43% up on its closing market value of £16bn8 last Friday. Softbank is said to pay in cash also “using” a long term loan from Japan’s Mizuho Bank.

ARM bought by Japanese Softbank for 32 billion dollars – [Link]

“Chipiplexing” efficiently drives multiple LEDs using few microcontroller ports


by Guillermo Jaquenod @

Actual microcontrollers have powerful bidirectional I/O ports, and you can use different techniques to fully exploit such capabilities. Recent Design Ideas described the “Charlieplexing” method as an effective way to drive M=N×(N–1) LEDs using only N bidirectional I/O ports and N resistors (reference 1 and reference 2). Unfortunately, using Charlieplexing allows you to drive only one LED at a time, so, when using a large number of LEDs, only a tiny slice of time is available to multiplex each LED: TDRIVE=T/M, where T is the PWM excitation period. As a consequence, to obtain a given average current and bright LEDs, you must excite them with a current M times higher, and you can’t usually obtain such peak currents from the microcontroller port.

“Chipiplexing” efficiently drives multiple LEDs using few microcontroller ports – [Link]