Arduino compatible high precision frequency counter

The concept of this board is to build an open, very versatile frequency counter, so it can be used to measure a wide variety of signals. It is designed to be customizable in every possible way.

Freq_LF_HF v1.0 board uses the famous AVR microcontroler Atmega328p-AU. This is not the newest ATMEL model but this chip is standard on Arduino UNO v3.0 board. It is a powerfull microcontroller and very small (TQFP- 32). This gives the opportunity for users to benefit from the Arduino community support and the many software libraries. The firmware uses a couple of the wonderfull functionnalities of this chip, namely the 16 bits timer, interrupts and comparator to an external precision voltage reference.

Versatile And Open Source LiPo bBattery Breadboard Power Supply

Orlando Hoilett from Calvary Engineering LLC designed a  versatile Li-Po battery breadboard power supply and wrote an Instructables on it. This power supply outputs 3.3V to the breadboard and takes input from a single-cell LiPo battery. The breadboard power supply also has the ability to charge the battery without needing to separate it from the circuit board. More importantly, this project is licensed under Open Source Hardware which means anyone can modify, distribute, make, and sell this design.

LiPo bread board power supply
LiPo breadboard power supply

Key Components

The complete BOM is available at the GitHub repository.

  • JST connector
    This connector connects directly to the LiPo battery.
  • 3.3V regulator, AP2210K
    3.3V logic is getting increasingly popular among electronics hobbyists and engineers. Also, boosting 3.7V of a LiPo battery to 5V can induce quite a bit of switching noise on the power supply. Linearly converting 3.7V to 3.3V is the best way to avoid this problem.
  • Battery Charger, MCP73831T
    This power supply has a charger built into the board so you can charge the battery without removing it from the power supply.
  • Voltage Selection Jumper
    The voltage selection headers are 3 pin male headers and they are labeled as 3.3V (or VReg) and VRAW (or LiPo). Connect the center pin to 3.3V to get power from the regulator. Connect the center pin to VRAW to get power directly from the LiPo battery.
  • DPDT Switch
    This switch lets you power down the board without removing the battery.
  • LED indicators
    LEDs are used to indicate the current status of the board.

Details

This board breaks out the LiPo battery to the breadboard power rails on both sides. It has a DPDT switch to power down the board. The AP2210K IC has an ENABLE pin which is pulled down to the ground using the DPDT switch in order to enter the low power mode. In low power mode, the regulator and all the LEDs get disabled and draws almost no current from the LiPo. More about the AP2210K regulator IC is on this datasheet.

LiPo breadboard power supply schematic
LiPo breadboard power supply schematic

Another great feature of this breadboard power supply as mentioned earlier is, it incorporates an MCP73831T LiPo battery charger IC. It is a widely used PMIC (power management integrated circuit) for charging LiPo batteries. The LiPo battery should be connected to pin 3 (VBAT) and 5V should be applied to pin 4 (VDD).

The chip starts charging as soon as it detects 5V input and stops charging when the battery is full. Charging current is limited to USB standard i.e. 100mA by connecting a 10.2K resistor between pin 5 (PROG) and ground. So, it’s completely safe to charge the battery from your laptops USB port. Other host microcontrollers can check the battery status using pin 1 (status pin) of MCP73831T.

Graphene Electronic Circuits with Atomic Precision

Essential electronic components, such as diodes and tunnel barriers, can be incorporated in single graphene wires (nanoribbons) with atomic precision. The result is a working electronic device that could be used in Graphene-based electronic switches with extremely fast operational speeds. Chemists at Utrecht University made this discovery together with their colleagues at TU Delft and the Aalto University in Finland.

Metal-semiconductor-metal junction (tunnel barrier) incorporated into a single graphene nanoribbon

The ‘wonder material’ graphene has many interesting characteristics, and researchers around the world are hard at work looking for new ways to utilise them. Graphene itself does not have the characteristics  to switch electrical currents on and off, however, so smart solutions must be found for that particular problem.

“The great thing about our solution is its atomic precision. By selecting certain precursor substances (molecules), we can code the structure of the electrical circuit with extreme accuracy”, explains research leader Ingmar Swart from Utrecht University.

The chemical pathway to graphene electronic circuits

Seamless Integration

The switch structureded on the principle of graphene nanoribbons. Previous research has shown that the ribbon’s electronic characteristics are dependent on its atomic width. A ribbon that is five atoms wide is an ordinary electric wire with extremely good conduction characteristics, but adding two atoms makes the ribbon a semiconductor.

“We are now able to seamlessly integrate a five-atom wide ribbon together with one that is seven atoms wide. That gives you a metal-semiconductor junction, which works as a diode”, according to Swart.

The work is published in Nature Communications, you can check it out on this link.

DIY Arduino Battery Capacity Tester

deba168 @ instructables.com writes:

I have salvaged so many old lap-top batteries ( 18650 ) to reuse them in my solar projects.It is very difficult to identify the good cells in battery pack.Earlier in one of my Power Bank Instructable I have told, how to identify good cells by measuring their voltages, but this method is not at all reliable.So I really wanted a way to measure each cell exact capacity instead of their voltages.

DIY Arduino Battery Capacity Tester – [Link]

Arduino FM Radio Project with TEA5767 Radio Module and a Nokia 5110 LCD Display

In this Arduino project video, educ8s.tv is going to build a simple FM Radio using the TEA5767 module with a Nokia LCD display:

In this video, we are going to build this. A simple FM Radio receiver on a breadboard. Let’s listen to it for a few seconds … As you can see the radio is working fine and we can hear some music coming out of it. I am transmitting some YouTube safe tracks using this inexpensive FM transmitter at this frequency. I am using the Nokia 5110 LCD display, to display the selected frequency, the signal strength, and a stereo icon if we are receiving stereo sound. The brains of the project are the small and inexpensive Arduino Nano. We can control the volume of the speaker using this potentiometer, and we can change the Radio frequency using this potentiometer. It is a fascinating project and relatively easy to build. Let’s see how to build it.

Arduino FM Radio Project with TEA5767 Radio Module and a Nokia 5110 LCD Display – [Link]

AutoPi makes your car intelligent

What if your car was intelligent like KITT in the 80’s TV show Knight Rider? With AutoPi all cars become intelligent and can have eyes, ears and a voice.

Until now all functionality and data from cars have belonged only to the manufacturers. With AutoPi the car owners can, as a cooperating community, take control over their own vehicles and data without having to be an engineer.

AutoPi.io is a Danish startup company and they have just launched their open Internet-of-Things platform for cars. It is the first extendable maker platform for cars, built on the revolutionary Raspberry Pi mini computer.

In less than 24 hours, their Kickstarter campaign has raised more than $20.000:

https://www.kickstarter.com/projects/autopi/autopiio-the-first-extendable-iot-platform-for-you

Diamond-Based MOSFETs Are Now Real

A research group at Japan’s National Institute for Materials Science (NIMS) has developed logic circuits equipped with diamond-based metal-oxide-semiconductor field-effect-transistors (MOSFETs) at two different operation modes – a first step toward the development of diamond integrated circuits operational under extreme environments.

Is Diamond Suitable for this?

In fact, diamond has high carrier mobility, a high breakdown electric field and high thermal conductivity. Therefore, it is a promising material to use in the development of current switches and integrated circuits. Specifically to operate stably at high-temperature, high-frequency, and high-power. However, it had been difficult to enable diamond-based MOSFETs to control the polarity of the threshold voltage. In addition, fabricating MOSFETs of two different modes on the same substrate was a challenge. The modes are:  a depletion mode (D mode) and an enhancement mode (E mode).

Thus, the research group has successfully developed a logic circuit equipped with modes. Thanks to threshold control technique that allowed them create hydrogenated diamond NOT and NOR logic circuits composed of D-mode and E-mode MOSFETs.

Micrograph of a fabricated logic circuit equipped with diamond-based transistors

This study was published in the online version of IEEE Electron Device Letters and it is available at the IEEE Electron Digital Library website. Also, check the official announcement for more details.

Meet Spritzer, Sony New Arduino

Sony has recently launched one of its new products, Spritzer! Spritzer is an Arduino-compatible board for IoT applications that has built-in GPS, audio codec, and low power consumption.

While it is Arduino-compatible, the board allows any developer to easily start app development using the free Arduino IDE and an ordinary USB cable. In fact, the board features a processing chip with a unique combination of low power consumption and a rapid clock speed of 156MHz. Thus, it is extremely versatile and it can be deployed for a vast range of use cases.

For the first time, the company demonstrated the board at Tokyo Maker Faire last month with a drone utilizing the GPS and the 6-axis sensor support, a smart speaker utilizing the audio functions, a self-driving line-tracing miniature car, and a low-power smart sensing IoT camera using the camera interface of Spritzer.

Sony Spritzer specifications

  • MCU – Sony CDX5602 ARM Cortex-M4F ×6 micro-controller clocked at up to 156 MHz with 1.5MB SRAM
  • Storage – 8MB Flash Memory, micro SD card
  • GNSS – GPS, GLONASS, supported
  • Audio – 3.5mm audio jack
  • Expansion I/Os
    • Digital I/O Pins – SPI, I2C, UART, PWM ×4 (3.3V)
    • Analog Pins – 6ch (3.3V range)
    • Audio I/O – 8ch Digital MICs or 4ch Analog MICs, Stereo Speaker, I2S, CXD5247 audio codec with 192 kHz/24bit High-Resolution audio
    • 2x camera interfaces
  • USB – 1x micro USB port for programming
Spritzer Block Diagram

“You’ll have to connect external module to get Bluetooth, WiFi, and LTE, a display up to 360×240 resolution can be used via SPI, all sort of sensors can be connected via the expansion header, the board is suitable for microphone arrays, and it can be powered by batteries thanks to a charger circuit and fuel gauge inside CXD5247 audio codec / PMU chip.” – CNXSoft

More details about the board will be available by 2018. Until then, check this Japanese official page about Spritzer, or this translated page.

Learn Arduino Easily with The Arduino Inventor’s Guide

Are you looking for Arduino tutorials? Already over-whelmed by the guides and videos available on the internet? Sparkfun is making Arduino and electronics easier for you with its new book ” The Arduino Inventor’s Guide”!

First of all, the authors of this book , Brian Huang and Derek Runberg, are both working in the department of Education at SparkFun Electronics. Since they are experienced in electronics and educating engineering in schools, they are working towards making electronics easy and fun.

In fact, this 10-project guide is a project-packed introduction to building and coding with Arduino microcontroller. With each hands-on project, total beginners learn useful electronics and coding skills while building an interactive gadgets. Accordingly, this guide is within the introductory-level educational series introduced by No Starch Press and Sparkfun.

“We wanted to share the magic that happens when you build something interactive with electronics,” says Huang. “The goal is to teach real, valuable hardware skills, one project at a time,” adds Runberg.

Content of the book

  • Introduction
  • Electronics Primer
    101 electronics
  • Project 1: Getting Started with Arduino
    Blinking an LED
  • Project 2: A Stoplight for Your House
    A miniature traffic light
  • Project 3: The Nine-Pixel Animation Machine
    An LED screen that displays animated patterns and shapes
  • Project 4: Reaction Timer
    A fast-paced button-smashing game to test your reflexes
  • Project 5: A Color-Mixing Night-Light
    A light-sensitive, color-changing night-light
  • Project 6: Balance Beam
    A challenging ball-balancing game
  • Project 7: Tiny Desktop Greenhouse
    A temperature-sensing mini greenhouse with an automated fan and vent
  • Project 8: Drawbot, the Robotic Artist
    A motorized robot that you can control
  • Project 9: Drag Race Timer
    A racing timer for toy cars
  • Project 10: Tiny Electric Piano
    A tiny electric piano that you can actually play!
  • Appendix: More Electronics Know-How

Reviews

The Arduino Inventor’s Guide will appeal to the gadget freak as well as those who like to put their own spin on things.” —Microcontroller Tips

“This is probably the best Arduino starter book out there! I highly recommend it for every library and classroom.” —Sequential Tart

To sum up, the book is available for $30 on No Starch Press as a printed book and for $25 as an Ebook. In addition, you can check this page for more insights. Also download Project 2: A Stoplight for Your House, and the sketches, templates, and diagrams used in this book.

1Amp Constant Current LED Driver Shield for Arduino Nano

1A Constant current LED driver shield for Arduino Nano has been designed for verity of LED related applications. The shield provides accurate LED current sink to regulate LED current in a string of LEDs or single LED. The LED current is mirrored from the current flowing from the RSET Preset PR1. On board 1W LED is used for testing purpose. External high Wattage LED or multiple LED string can be connected by pulling two wires from the PCB and this shield fit directly on back side of Arduino Nano. Shield also has on board tactile switch connected to Digital D2 pin using pull down resistor if required for any application. On board preset helps to set the maximum constant current. PWM input pin connected to Digital pin D6 of Nano to control the LED intensity. Example code FADE-IN/FADEOUT helps to test the shield.

1Amp Constant Current LED Driver Shield for Arduino Nano – [Link]