Air pressure sensors in smartphones

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Dr. Thomas Block has a great article about air pressure measurement on smartphones and which benefits this may have.

Today’s smartphones utilize a wide array of accelerometers, gyroscopes and various other sensors in their designs. Relatively unknown is the barometric pressure sensor, which measures air pressure. These sensors are currently being integrated into premium-grade smartphones, but are also becoming more common in mainstream phones or wearables such as fitness trackers and Internet of Things (IoT) applications.

Air pressure sensors in smartphones – [Link]

Circuit provides cold-junction compensation

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Mark Maddox @ edn.com has a design idea on cold-junction compensation using AD7708.

The accuracy of any circuit or system that uses a thermocouple to determine the temperature of a process is limited by the accuracy of the method used to perform cold-junction compensation. In a thermocouple measurement, two wires of dissimilar metal join together at the “hot,” or measurement, junction. The isothermal termination of the thermocouple wires provides a second “cold,” or reference, junction. The potential across the thermocouple is proportional to the temperature difference between the two junctions.

Circuit provides cold-junction compensation – [Link]

100Vin, 5W out regulator uses primary-side control

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LT8303 is a monolithic flyback regulator in a TSOT-23 package that simplifies the design of isolated DC/DC converters. By sampling the isolated output voltage directly from the primary-side flyback waveform, the part requires no opto-isolator, LT1431 or third winding for regulation. by Graham Prophet @ edn-europe.com

The LT8303 operates over a 5.5V to 100V input voltage range, has a 0.45A/150V integrated DMOS power switch and delivers up to 5W, suiting it for a range of telecom, datacom, automotive, industrial, medical and military applications. The output voltage is set with one external resistor and the transformer turns ratio. Several off-the-shelf transformers are identified in the data sheet. The LT8303 operates in boundary mode, which is a variable frequency current mode control switching scheme, typically resulting in ±5% output voltage regulation over the full line, load and temperature range. Boundary mode enables the use of a smaller transformer compared to equivalent continuous conduction mode designs. The high level of integration and the use of low ripple Burst Mode operation result in a simple to use, low component count and high efficiency application solution for isolated power delivery.

100Vin, 5W out regulator uses primary-side control – [Link]

Low noise Mini Electret Microphone PreAmplifier

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The single supply microphone pre-amplifier amplifies the output signal of an electret capsule microphone to audio line levels. An op amp is used as a trans-impedance amplifier to convert the output current from the microphone in to a signal level voltage. The circuit works with 9V so it is good choice for battery operated systems.

Features

  • Supply 9V DC
  • Current Approx. 3mA
  • On Board Microphone
  • Very thin and narrow PCB

Low noise Mini Electret Microphone PreAmplifier – [Link]

Printable battery paves the way for custom-shape power sources

A new type of batteries called “Printable Solid-State (PRISS) Lithium-Ion Batteries” was designed by a group of researchers from the Ulsan National Institute of Science and Technology (UNIST, South Korea). The new battery is created from consecutive layers of printed composite materials.

Representation of the PRISS Battery production process
Representation of the PRISS Battery production process

With a simple stencil printing process followed by ultraviolet cross-linking, a solid-state composite electrolyte (SCE) layer and SCE matrix-embedded electrodes are consecutively printed on arbitrary objects of complex geometries, eventually leading to fully integrated PRISS batteries. Then the rheological properties of SCE paste and electrode slurry adjusted to get thixotropic fluid characteristics, along with well-designed core elements.

This technology yields many positive features, it eliminates the need for conventional microporous separator membranes and the extra processing steps of solvent drying and liquid-electrolyte injection.

With this new type of batteries, unlimited forms and sizes of batteries will be available for our various projects.

Source: Elektormagazine

8 Channel Relay Board with onboard 5V regulator

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This is a general purpose relay board accepting 8 inputs to drive 8 relays providing control requirement in your project. This board can also be used as an add-on card for the various Development board that we provide and various microcontroller boards.

Features

  • Robust Design using NPN transistor to drive each relay
  • Relay On Indicator LED for each of the eight relays.
  • Back EMF / Surge protection diode across each relay to protect driving circuit.
  • 3 Pin PBT connector for connecting load to the relay.
  • Reverse Polarity protection diode (D17) provided.
  • 2 pin PBT provides easy connection of power source to the PCB.
  • On Board Voltage Regulator U1 (7805) provides +5V DC supply to ongoing interface circuit connected to this board.
  • A 10 pin Relimate Connector provides easy connect of this PCB to the driving interface.
  • Supply voltage 12 ~ 15 V DC

8 Channel Relay Board with onboard 5V regulator – [Link]

Temperature-to-period circuit provides linearization of thermistor response

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by S Kaliyugavaradan, Anna University, Madras Institute of Technology, Chennai, India; Edited by Brad Thompson and Fran Granville -November 10, 2005

Designers often use thermistors rather than other temperature sensors because thermistors offer high sensitivity, compactness, low cost, and small time constants. But most thermistors’ resistance-versus-temperature characteristics are highly nonlinear and need correction for applications that require a linear response.

Temperature-to-period circuit provides linearization of thermistor response – [Link]

Review: pi-top DIY laptop for your Raspberry Pi

The pi-top converts your Raspberry Pi into a complete RPi notebook. by René Bohne @ elektormagazine.com

It comes as a nice kit that is very easy to assemble thanks to a great construction manual. We created a video of the assembly. If you have any questions, feel free to leave comment on Youtube or below this article!

Review: pi-top DIY laptop for your Raspberry Pi – [Link]

Arduino Tutorial: Color OLED SSD1331 display with Arduino Uno

In this video educ8s.tv shows us how to use the Color OLED display with the SSD1331 driver with Arduino. It’s very easy!

A few weeks ago, I discovered this promising new display on Banggood.com and I thought that it might be useful in some of our projects so I bought it right away. It is a Color OLED display! I have used this small monochrome OLED display in some of my previous projects and I love it. So, I couldn’t resist having a color OLED display. I have loaded a demo sketch and as you can see the display is fast and bright. It is brighter than LCD displays because it uses the OLED technology and of course it uses less power. The power usage will vary with how many pixels are lit, the maximum is around 25mA. The cost of this color OLED display is around $11.

Arduino Tutorial: Color OLED SSD1331 display with Arduino Uno – [Link]