Cheap homemade 30 MHz – 6 GHz vector network analyzer

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Henrik Forstén has done amazing job designing a homemade vector analyzer with the goal to fit it’s budget of 200EUR. The design is open source and available on github.

Vector network analyzer (VNA) are used to measure scattering parameters of high frequency circuits. When frequency is high enough the reflections of the waves start to matter and distributed effects need to be taken into account. VNA can be used to analyze reflection and transmission coefficients of circuits at high frequencies.

Cheap homemade 30 MHz – 6 GHz vector network analyzer – [Link]

Projecta: A Solution For PCB Printing

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Projecta, the Affordable & Faster PCB Prototyping Machine is going to launch their kickstarter campaign soon. Check the draft kickstarter page and feel free to post your feedback.

Projecta is an affordable desktop CNC machine optimized for making circuit boards in new innovative way.

Projecta: A Solution For PCB Printing – [Link]

Siglent oscilloscope SDS1102X review

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Harry Baggen @ elektormagazine.com reviews the Siglent SDS1102X oscilloscope.
Before we take a look at the instrument itself, I would like to say something about the characteristics of an oscilloscope for ‘small users’. What do you really need for your daily tasks? Even the cheapest models from Chinese manufacturers already have a sample rate of 500 MS/s or 1 GS/s, much more than what the typical electronics engineer needs. More important is the input bandwidth, which is an indication of the quality of the analog input stage, which, for example, could be 50 or 100 MHz. Most electronic engineers work on circuits with frequencies up to a few megahertz and then a simple USB scope with a sample rate of 100 MS/s and an input bandwidth of 10 MHz is already more than sufficient.

Siglent oscilloscope SDS1102X review – [Link]

Dual 90V/10A Unregulated Power Supply

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This project is designed to provide symmetrical output unregulated, high voltage, high current for your demanding needs.  Right choice for Audio Amplifiers, Power Drivers, Motor Drivers etc

Features

  • Input – maximum 65 VAC center-tap, 10Amp
  • Symmetrical unregulated, individually fused outputs
  • 10A bridge rectifier on board
  • LED indication for both the outputs
  • PCB mounted LUGS for connecting of input and output
  • Four mounting holes of 3.2 mm each
  • PCB Dimensions 154 mm x 84 mm

Dual 90V/10A Unregulated Power Supply – [Link]

Inkjet printing of text or photos as solar cells

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by Denis Meyer @ elektormagazine.com:

Research is in progress at the University of Aalto in Finland on the development of a process for inkjet printing of text, photos or any illustrations as solar cells. The idea is not new but these researchers are covering new ground which will allow the use of ordinary materials. According to Janne Halme: “The difficulty has been the development of solvents which are both clean and photovoltaic and give a good print quality”.

Inkjet printing of text or photos as solar cells – [Link]

Combo sensors fit wearable devices

Kionix KXG0708
Two combination accelerometer-gyro sensors, the KXG07 and KXG08 from Kionix, a subsidiary of Rohm, provide six axes of motion sensing. Both devices feature a configurable low-power architecture and a large 4096-byte FIFO buffer with timestamps for use in gaming systems, smart phones, and wearable devices. by   @ edn.com
Unlike conventional sensor signal-detection methods based on amplitude detection, the KXG07 and KXG08 use a proprietary phase-detection scheme that contributes to smaller designs, while enabling full high-speed operation of the onboard accelerometer, gyroscope, and temperature sensor at power consumption levels as low as 0.2mA, allowing for always-on operation. Each device offers I2C and SPI digital outputs with user-programmable gyroscope full-scale ranges of ±64°/s, ±128°/s, ±256°/s, ±512°/s, ±1024°/s, and ±2048º/s and user-programmable accelerometer full-scale ranges of ±2 g, ±4 g, ±8 g, and ±16 g.

Combo sensors fit wearable devices – [Link]

The IoT Project Builder “myDevices” Has Added Arduino Support

“myDevices”, creators of IoT platform Cayenne, announced in a press release a partnership with Arduino to integrate Arduino support in their system. The partnership seems to be with Arduino SRL not with Arduino LLC.

The currently supported Arduino boards, beside variety of sensors and actuators, are:

  • Arduino Due
  • Arduino Leonardo
  • Arduino Mega
  • Arduino Nano
  • Arduino Pro Micro
  • Arduino Pro Mini
  • Arduino Uno
  • Arduino Yun
  • Ethernet and WIFI Shields

To write your application code you need to add Cayenne library to your Arduino IDE.

How to use Arduino with Cayenne:

An overview of Cayenne:

Cayenne is a drag and drop IoT project builder, gives the hardware developers the ability to have their own apps without having any background in web or mobile development.

Cayenne platform has two major parts,a Cayenne Mobile Apps to monitor and control your IoT projects remotely from the Android or iOS Apps, and Cayenne Online Dashboard with customizable widgets to visualize data, set up rules, schedule events.

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The main Cayenne features are:

  • Drag-and-drop widgets.
  • Visualize Arduino sensor data.
  • Create triggers & alerts between different platforms.
  • Ability to create widgets for any connected sensor or actuator.
Creating a Trigger
Creating a Trigger

Visit the documentation and resources pages to know more about how to use Cayenne platform.

D7S Vibration Sensor From Omron

Omron announced a new seismic sensor and claims it’s the world’s smallest in size.

D7S sensor is a MEMS 3-axis acceleration sensor featuring OMRON’s unique SI value calculation algorithm, which has a high correlation with the seismic intensity scale that indicates the magnitude of an earthquake and provides higher-precision judgment of seismic intensity scales.

The below diagram describes how D7S works

D7S - Operation Chart
D7S – Operation Chart

The sensor has two open-drain outputs INT1 and INT2. INT1 goes active (low) when shutoff judgment condition and collapse detection condition are met (earthquake level 5 or higher), INT2 goes active (low) during earthquake calculations, offset acquisition and self-diagnostic processing.

I2C is used for communication with the sensor for settings and obtaining earthquake-related information.

D7S - Circuit Diagram
D7S – Circuit Diagram

D7S

D7S is a surface-mount compact module with 10.9 × 9.8 mm dimensions. I found the new sensor on Mouser and the price per unit is about $22 (USD) for 1-unit quantity order.

[Datasheet]

[Product Page]

Arduino Geiger–Müller counter with LCD display

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Bob tipped us with his latest project. It’s a custom Arduino shield able to communicate with a Geiger-Muller counter and display data on a LCD display. The data are displayed in two layouts: bar graph of the pulses in one minute interval and histogram of the gathered data.

In the previous posts I’ve described a simple Geiger–Müller counter and various experiments with this device. Today I would like to present Arduino project to communicate with a Geiger-Muller counter, gather data and present it to the user. The device is based on Arduino Uno, Nokia 5110 LCD and homemade shield.

Arduino Geiger–Müller counter with LCD display – [Link]

Disconnect circuit for 12 volt lead acid and lithium batteries

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KA7OEI designed a circuit that disconnects the battery when it over-discharges. He writes:

The avoidance of overcharging is usually pretty easy to avoid: Just use the appropriate charging system – but overdischarge is a bit more difficult, particularly if the battery packs in question don’t have a “protection board” with them.

Lead acid batteries (almost) never come with any sort of over-discharge protection – one must usually rely on the ability of the device being powered to turn itself off at too-low a voltage and hope that that threshold is sensible for the longevity of a 12 volt battery system.

Disconnect circuit for 12 volt lead acid and lithium batteries – [Link]