ESP8266 based e-paper WiFi weather station

Erich Styger documented his experience building Daniel Eichhorn’s e-paper weather station with a custom enclosure:

Using e-paper for a weather station is an ideal solution, as the data does not need to be updated often. By default, the station reaches out every 20 minutes for new data over WiFi and then updates the display. Daniel Eichhorn already has published kits for OLED (see “WiFi OLED Mini Weather Station with ESP8266“) and touch display (see “WiFi TFT Touch LCD Weather Station with ESP8266“). I like them both, but especially the TFT one is very power-hungry and not really designed to work from batteries. What I would like is a station which can run for weeks.

ESP8266 based e-paper WiFi weather station – [Link]

STMicro Introduces 20 Cents MCU in 8-Pin Package

STMicro has launched STM8S001J3, a new 8-bit micro-controller that sells for $0.20 per unit in 10k quantities. STM8S001J3 is also the first STM8 MCU offered in 8-pin package (SO8N), and should compete with some of the Microchip Attiny or PIC12F series micro-controllers.

STM8S001J3 has small package and little number of pins, but still it embeds rich set of peripherals. Below some of key features of this device:

  • Core and system
    • Flexible clock control capable to use three clock sources: 2 internal (HSI 16MHz, LSI 128kHz), 1 external clock input.
    • Wide operating voltage range: from 2.95V to 5.5V
    • 5 I/Os
    • 8- and 16-bit timers
  • Memories
    • 8k Flash
    • 1k RAM
    • 128 Bytes EEPROM
  • Conenctivity and debug
    • UART
    • SPI
    • I2C
    • Single Wire Interface Module
  • Analog
    • 10-bit ADC with 3 channels

Nerdonic Atom X1 is the World’s Smallest 32-bit Arduino Compatible Board

Tiny 32-bit Dev Board. 14.9mm², Breadboard, 0.95g, 3-20V input, I²C, 8 PWM, Serial, 6 ADC, Prog LED.

There is a new board in the ecosystem which claims to be the world’s smallest 32-bit Arduino board. The name of it Atom X1 and measures 14.9×14.9 mm.

Atom X1 specifications:

  • MCU – Microchip Atmel  SAMD21 Cortex M0+ MCU @ 48 MHz with 256KB flash, 32KB SRAM
  • I/Os via 2x 5-pin 2.54mm pitch headers
    • Up to 8x digital I/O
    • Up to 8x PWM
    • Up to 6x analog (ADC)
    • 1x UART
    • 1x I2C
    • 1x reset
    • Limits – 3.7V, 7mA
  • USB – 1x micro USB port
  • Programming – via micro USB port or SWD header
  • Misc – Power LED, user LED, button
  • Power Supply
    • 3.3-20V (regulated to 3.3v) via power Pin 1
    • 3.3V via power pin 2
    • 5V (regulated to 3.3v) via Micro USB port
    • Current Draw Atom X1 = ~10mA
  • Dimensions – 14.9 x 14.9 x 4.4mm
  • Weight – 0.95 grams

The board is breadboard compatible, pre-flashed with Arduino Zero bootloader, and can be programmed in the Arduino IDE just like the original board.

The project has been launched on Indiegogo. Early bird rewards start at 10 GBP (~$13.2 US) for the board with shipping adding 2 GBP to the UK, and 7 GBP to the rest of the world. Delivery is scheduled for December 2017.

Rigol general-purpose 200MHz scopes from under €600

RIGOL Technologies introduces its new DS2000E Series Oscilloscope, a 200MHz, 2 channel scope that continues RIGOL‘s tradition of combining unmatched capabilities at unprecedented price points to transform the test and measurement industry.

The DS2000E is available at either 100MHz or 200MHz bandwidths.  All models provide 2 analog channels with 50 Ω input impedance standard.  With real-time sample rate of 1GS/Sec (on both channels), memory depth of up to 28Mpts standard, and waveform capture rate up to 50,000 wfms/sec, the DS2000E provides the raw instrument performance required to meet today’s more advanced debug challenges.  When coupled with the large 8 inch WVGA intensity graded display, complete network connectivity, hardware waveform record/playback, serial trigger and decode, and other advanced analysis capabilities, starting at just $647, engineers and technicians will see RIGOL has again transformed the price performance assumptions in the Basic Oscilloscope Market.

Rigol general-purpose 200MHz scopes from under €600 – [Link]

Bosch BME280 sensor combines pressure, humidity and temperature measurement

Bosch Sensortec announces a world first in sensor technology: the BME280 Integrated Environmental Unit combines sensors for pressure, humidity and temperature in a single package. This unique sensor has been developed to support a broad range of emerging high performance applications such as indoor navigation, home automation control, personalized weather stations and innovative sport and fitness applications. The precise altitude measurement function of the BME280 is a key requirement in applications such as indoor navigation with floor tracking where exceptional accuracy, low temperature drift and high resolution are needed. Additionally, the BME280 has a best-in-class response time of just one second for humidity determination, excellent ambient temperature measurement and low energy consumption.

More precise measurement at lowest power consumption

With a small footprint of just 2.5 x 2.5 mm2and a height of 0.93 mm in a space-saving 8-pin LGA package, the sensor offers high design flexibility and is ideally suited for mobile devices with limited space such as smartphones, tablets, smart watches and electronic wristbands. Very low current consumption of only 3.6 µA (at 1 Hz) makes the BME280 Integrated Environmental Unit particularly suitable for battery-driven applications. Three power modes and separately configurable oversampling rates for pressure and temperature measurements allow designers to adapt the BME280 to a wide range of use cases.

The humidity sensor within the Integrated Environmental Unit measures relative humidity (0% to 100%) across a wide temperature range from -40°C to +85°C with a fast response time of less than 1 second. The humidity measurement accuracy is ±3% with a hysteresis of 2% or better, and the temperature reading accuracy is within 0.5°C.

more details on the Bosch Press Release.

Three Ways to Make Arduino Works As A USB/TTL Converter

Even if you have years working with electronics, you will still find some simple hacks that you never thought about before. Personally and to save money, when I was a student with a very limited budget I knew that my Arduino UNO can work as a USB/TTL(serial) converter. I used to remove the Atmega328P from my Arduino UNO R3 board in order to use the board as a converter not as a development board.

Why we need to do some tweaking to Arduino in order to use 0 and 1 pins for direct USB <-> UART conversion? This is because of what’s called fan-out (fan-out of a logic gate output is the number of gate inputs it can drive). In Arduino UNO case, the RX & TX lines (pins 0 and 1) are connected to FT232RL/Atmega8U2 USB to TTL bridge and to the Atmega328P MCU (check the schematic). So using the same pins with an external connections without doing any changes to Arduino UNO board probably won’t work.

Patel Darshil over listed three ways to make Arduino works as a USB/TTL converter:

Hack #1: Set Pin 0&1 Mode to Input Mode

This is done using code:

Pin Mode Set Arduino

But why this solves the problem? Well, GPIO can operate in two modes, input and output. In the input mode the equivalent impedance of the pin is too high; therefore, the Arduino/Atmega328P’s pins will have almost no electrical effect to the converter RX/TX pins.

Hack #2: Keep Atmega in Reset Mode

Just connect the RES pin with GND (the bold red wire in the image bellow)

Arduino Reset
Image Courtesy of Patel Darshil

GPIOs are configured using special registers. For example, Atmega has GPIO port data direction register (DDR) to set the GPIO as an input or an output for each port. The value of this register is cleared during reset. Therefore, the MCU’s GPIOs mode will be input. This means high impedance, subsequently.

Hack #3: Remove The MCU

This is the common way used by most Arduino UNO users, but it’s not applicable when it comes to new versions of Arduino; where, the MCU is SMD and can’t be removed.

A New Soundproof Air-Transparent Window

Imagine you have a window that isolates noises and passes only nature sounds like sea waves in addition to fresh air. Seems like it will happen in dreams only, right? Actually, researchers from South Korea, bring this window from dreams to the real.

Soundproofing is difficult and expensive, it usually relies on transferring sound into a medium which absorbs and attenuates it. But this also will stop the airflow. Sang-Hoon Kima and Seong-Hyun Lee have successfully build a new window that allows airflow to pass without sound and noises.

The new design is simple and depends on two acoustic conditions, strong diffraction and negative bulk modulus.

Strong Diffraction

At first, this method makes the sound waves diffused into a customized resonator called diffraction resonator. This resonator maximizes the diffraction impact with its air hole in the center of the body. In addition, the diameter of the hole will control the range of frequencies to restrict. Only waves with a wavelength smaller than the diameter can pass through the hole.

Artificial atoms of diffraction resonators. Diameters of the air holes: 20mm for (a1), (a2), and (a3), and 50mm for (b1), (b2), and (b3). There are three structures: one room for (a1) and (b1), two rooms for (a2) and (b2), and four rooms for (a3) and (b3).

Negative Bulk Modulus

A material’s bulk modulus means its resistance to compression. It is also an important factor in determining the speed at which sound moves through it. So, a material with a negative bulk modulus exponentially attenuates any sound passing through it.

While it is hard to find a solid material having a negative bulk modulus, Kima and Lee have designed a new sound resonance chamber. This chamber consists of two parallel transparent acrylic plastic plates. The efficiency of the double-glazed window is measured by getting the sound into the chamber. To maximize the efficiency, they drilled a hole through each plate. This double-glazing window has also used as a building block to make windows in larger sizes.

Designs of the medium-sound separator. 20mm (left) and 50mm (right). It is composed of the three kinds of artificial atoms which are connected in series and parallel.

There are several applications of this windows, changing the size of the holes makes the windows tunable for certain frequencies. To know more about this research review this paper.

Voladd: The First Fully Integrated 3D Printer

The Spain based Voladd company introduces their fully integrated 3D printer on a kickstarter campaign. The heart of printer is a BeagleBone Black single board computer running Debian Linux that connects to cloud service directly without need of an attached computer.

With your smartphone, tablet or laptop, you have the power to search for thousands of available objects in the online platform connected to your Voladd 3D printer. It’s as easy as pressing play and listening to a song. No downloads. No software installation. No previous knowledge of 3D printing required. Just select your desired object and make it. It’s as simple as that.

Kickstarter pricing starts with early bird packages of 499 Euros ($591), with shipments due in December.

Researchers Developed Low Cost Battery From Graphite Waste

Lithium-ion batteries are flammable and the price of the raw material is increasing. Scientists and engineers have been trying to find out a safe yet efficient alternative to the Lithium-ion technology. The researchers of Empa and ETH Zürich have discovered promising approaches as to how we might produce powerful batteries out of waste graphite and scrap metal.

Kostiantyn Kravchyk and Maksym Kovalenko, the two chief researchers of the Empa’s Laboratory for Thin Films and Photovoltaics, led the research group. Their ambitious goal is to make a battery out of the most common elements in the Earth’s crust – such as graphite or aluminum. These metals offer a high degree of safety, even if the anode is made of pure metal. This also enables the assembly of the batteries in a very simple and inexpensive way.

In typical lithium-ion battery design, the negative electrode or anode is made from graphite. This new design, however, uses graphite as the positive electrode or cathode. In order to make such batteries run, the liquid electrolyte needs to consist of special ions that form a kind of melt and do not crystallize at room temperature. The metal ions move back and forth between the cathode and the anode in this “cold melt”, encased in a thick covering of chloride ions.

Alternatively, large but lightweight and metal-free organic anions could be used. But, this raises some questions which cannot be solved easily – where are these “large” ions supposed to go when the battery is charged? What could be a suited cathode material? In comparison, the cathode of the lithium-ion battery is made of a metal oxide which can easily absorb the small lithium cations during charging. This does not work for such large organic ions.

To solve the problem, Kovalenko’s team came up with a unique and tricky solution: the researchers turned the principle of the lithium-ion battery upside down. In Kovalenko’s battery, the graphite is used as a cathode; i.e., the positive pole. The thick anions are deposited in the intermediate spaces in the graphite. While searching for the “right” graphite, they found that waste graphite produced in steel production (known as kish graphite) works the best as a cathode material. Natural graphite is suitable when it is in the form of coarse flakes and not too finely ground.

Sensor board for micro:bit

The MonkMakes Sensor Board for micro:bit allows you to sense sound level, temperature and light level.


  • 3V and GND connections can be made from either side and allow you to power a second board such as the MonkMakes Relay Board or MonkMakes Speaker.
  • LED ‘power on’ indicator
  • Reverse polarity protection
  • All three sensors are analog and can be connected to pins P0, P1 and P2 using alligator clips.

Sensor board for micro:bit – [Link]