Make your own Attiny2313 development board


In this tutorial you will learn how to build a basic development board for Attiny2313 microcontrollers.

Did you ever want to make your own development board with microcontroller and you didn´t know how .In this instructable I will show you how to make it.All you need is knowledge in electronics, designing circuits and programming.

Make your own Attiny2313 development board – [Link]


How to use a fully differential amplifier as a level shifter

7446.Figure 1.PNG-1230x0

Loren Siebert @ discuss about how to interface signals that have a reference voltage that isn’t 0V while preserving the DC information.

Many signal paths are direct current (DC)-coupled, and this can lead to challenges when different portions of the signal path require different operating conditions. Many portions of a signal path are ground-referenced, where a signal varies at about an average or mid value of 0V. If all signals had the same reference voltage, DC coupling would be very easy. Unfortunately, that is not the case. Devices operating from a single supply like mixers or analog-to-digital converters (ADCs) will typically have a reference voltage (common mode) that is not 0V. Interfacing these devices while preserving DC information can be challenging.

How to use a fully differential amplifier as a level shifter – [Link]

MemType USB Stick With All Your Passwords

Noela and Miguel from Area0x33 made a really helpful tool on They designed a fully open source hardware USB stick to store your username/password pairs on.


MemType uses Atmel ATtiny85 MCU and V-USB to do the communication over USB. V-USB is software-only implementation of a low-speed USB device for Atmel’s AVR microcontrollers.

Memtype Schematic
Memtype Schematic

Memtype uses [NOEKEON] to encrypt the stored values with 2K flash reserved for storage, and a PIN number, settable by user, to protect your information if your stick was lost. There is no need for any drivers, because Memtype is numerated as a keyboard. You just need to plug it in usb, enter the PIN code, and then choose your username/password. It uses 5-way tactile switch as user input.

To make things easier, they labeled each username/password with names, and with import and export features supported in .xml form. These features managed by a software tool called MemTypeTool.


You can purchase Memtype from tindie for 24$, and source files are available on Github for both hardware and software.

For more information on how Memtype works, please watch this video below:

Differential Pair Routing and Meander Tool in Eagle CAD

When you see some board designs, especially ones with high speed signals or differential pair signals, then you will notice a lot of zigzag/meander lines on PCB.

If you’re wondering whether you can do differential pair routing, then the answer is simply yes by using Meander tool.

First, let’s see how we can draw Differential Pair in Eagle. To do so, follow these steps:

  1. Select two lines, give one of them any descriptive name you want ended with _n and the give the
    same name to the other except that it should be ended with _p.
  2. When you route them, you will notice that trace is drawn for both of them, if you want to trace
    just one, then you need to press esc.
  3. You can determine the clearance between both of them while drawing by changing clearance
    value from default class (type “class” in command line).

differential pairEagle

Now, to use Meander tool, follow these steps:

  1. Select Meander Tool from the left sidebar.
  2. When you click on any route, you will see the length of this route. You will need to select a
    reference length to measure if you want Menders to match the length. Note that there is
    no need to have any special name for these two lines. To select the reference wire
    click ctrl+left mouse button on the trace. Now hit on any trace with left mouse button
    and it will be compared to the reference length (a percentage will be shown).
  3. If you failed to draw the Meanders, then try a smaller value of clearance for default class
    (type “class” in command line).


They’re ‘Not’ JUST Capacitors

James Lewis from Kemet has made a presentation to address some of misconceptions about capacitors like how you should de-rate capacitors.
James said that de-rating depends on the chemistry and configuration of a particularly capacitor.  So he started by asking a question: Should capacitors be de-rated 50%? And the answer was not a simple true or false. It was: it depends…

James talked about the typical construction of Multilayer Ceramic Capacitor(MLCC), Aluminum Electrolytic(wet one), Tantalum, Polymer Electrolytic and Supercapacitors.

James talked about the Temperature Coefficients diagram for various types of Ceramic Capacitor like: YV, Z5U, X5R, X7R, U2J and C0G [Ceramic Capacitor].

Temperature Coefficients diagramWe can see that MLCC capacitance ranges, and Coefficients depend on type.

Another key point was about capacitance change vs DC bias in MLCC. It’s about the role of package size in capacitance lose over DC bias. He compared 10nf and 6.3v rated 1206 package capacitor with same one in 0805 package. Results showed that the 1206 one lost 2% of capacity, while the 0805 lost 50% at 6V. James said that the 0805 package is thinner than the 1206 one, so we need to put more layers into the design to get more capacity. So thinner package leads to worse coefficients.

He pointed out that the capacitance of Wet Aluminum Capacitors is affected on shelves, and he explained how to reform/self-heal them.

James also explained why it’s safer to use Polymer Electrolytic rather than using Tantalum Capacitors, and why Polymer Electrolytic when fails, it fails safely.

TantalumsHe ended his presentation up by talking about Supercapacitors, and he made a walkthrough the tools Kemet provides:
KEMET Catalog App for Mobile Devices
Capacitor Simulator K-SIM 
KEMET Engineering Center (capacitor technical content)

[Presentation Slides]

Temperature controlled Fan


Ahmad Al-Shalabi and Bassma Karbouj show us how to control a DC fan using easy to find components. The fan works when temperature reach into pre-specified threshold.

The purpose of this project is creating a cooling system by controlling in a DC fan in a simple way without using Microcontrollers or Arduino but by using electronic components that it’s very simple and available. The DC fan controlling achieved by a Thermistor and which is a type of resistor whose resistance is dependent on temperature. there is two type of thermistor that is NTC ” Negative Temperature Coefficient” , PTC ” Positive Temperature Coefficient “

Temperature controlled Fan – [Link]

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]