Test/Measurements category

Measuring seismic activity using ProtoCentral OpenPressure

Seismic activity or “Vibrations of the earth” is measured using ProtoCentral’s OpenPressure 24-bit DAQ System.

A geophone is a magnetic device used to measure the Earth’s normal vibrations (some abnormal during events such as earthquakes). These movements are also present when there is a small explosion (commonly used for mining and exploration purposes).

Measuring seismic activity using ProtoCentral OpenPressure – [Link]

Increasing Battery Life With UB20M Voltage Detector

Engineers at the University of Bristol have developed a three terminal pico-power chip that can cut standby drain in sensor nodes – even compared with today’s low-power microcontrollers.

It does this by replacing the low duty-cycle sleep-wake-sleep pattern used on MCU-based sensor monitors, with ‘off’. A voltage detector powered by the sensor – there is no other power source –  starts the processor when the sensor produces a voltage.

At 5pA (20°C 1V), power draw from the sensor through the input/supply pin is so low that the chip can directly interface with high-impedance sensors such as antennas, piezo-electric accelerometers, or photodiodes. With so little current required, the chip does not collapse the sensor voltage.

“It will work from five infra-red diodes in series, powered from a TV remote control 5m away, or an un-powered accelerometer”, Bristol engineer Bernard Stark told Electronics Weekly.

Called UB20M, the only power it draws from the system is 100pA(max) leakage through its open drain output transistor. Input threshold is set at 0.6V.

Once the sensor presents greater than 0.6V to the input, the output FET turns on (RDSon~800Ω), and its low resistance can either be used to turn on a p-FET to power up a microcontroller, or can wake a microcontroller from sleep.

In an extreme application example, said the University, an earthquake detector could be held in sleep for years, until a tremor caused the chip to wake its host.

Despite its impedance and sensitivity, the device can withstand 20V on its input/supply pin, and it has ESD protection. Maximum output pin parameters are 5.5V 7mA. Output turn-on time is 0.25μs, while turn-off depends on load resistance and capacitance – typically 8μs with a 5MΩ load and 180μs with 100MΩ.

Because patents are pending, exactly how the chip works is not being disclosed. It has around 40 transistors, and is made on a 180nm CMOS process, is all Stark could say.

Samples are available – through a multi-project wafer deal with Europractice and IMEC, fabricated at AMS in Austria, and the University has created an evaluation board. Due to Europractice and IMEC going the extra mile, said Stark, samples are in SOT323-5 rather than clunky research packages.

The team cautions that anyone trying the chip will need to understand high-impedance circuits, as otherwise stray mains fields, for example, will trigger it continuously and the output transistor will remain on. Lengthy sensor connections should be avoided.

In general, the sensor has to be connected to the input/supply pin with enough parallel resistance to leak away stray charge and ensure the UB20M turns off.

“We are now working on ways of bringing other power drains such as data-capture, computation, and transmission, to within the nW-power budget of a sensor, completely eliminating batteries from sensor nodes,” said the University. “An example of this (right) is where power management with a few tens of nW quiescent is actively matching its input impedance to an 80MΩ energy harvester with 10 ms intermittent output pulses.”

UB20M data sheet and eval board details can be reached from this introductory web page, and there is an introductory video.

Source: Electronics Weekly

Mini Digital Barometric Altimeter

I found on Ebay very nice, small 12v 23A battery holders for PCB mounting style and decided to fit the SMALL DIGITAL BAROMETRIC ALTIMETER just on the back of the holder.

So basically this is the same schematic as the SMALL DIGITAL BAROMETRIC ALTIMETER, however I moved some of the connections to different MCU pins because of PCB space limitations.

Mini Digital Barometric Altimeter – [Link]

Dosime Radiation Meter

Dosime Radiation Meter: Know The Radiation Surrounding You Using Smartphone

Radiation is always present in our lives. We can’t see, taste, feel or smell it, but it exists. Excessive exposure to ionizing radiation may cause potential damage to our health. The new Dosime device helps you to track and understand radiation exposure in your environment and display them using an app on your smartphone.

Dosime Radiation Meter For your Smart Phone
Dosime Radiation Meter For your Smart Phone
Pie Chart of Radiation Sources
Pie Chart of Radiation Sources

Dosime is a hybrid smart home and wearable device. The device weighs just 57 grams and is only 6.8 centimeters in height, making it extremely easy to take it with you everywhere. Now, the most important question is, how necessary is it to measure radiation level if someone is not living by a nuclear plant? Well, a nuclear plant is not the only one who emits radiation. 82% of the radiation we are exposed to comes from natural sources. The remaining 18% comes from man-made sources. So, yes. It is necessary to measure radiation level in your environment. On their website the company says:

Healthy living includes managing your environment, including factors you can not perceive. Knowledge of radiation exposure empowers you to make informed decisions about your wellbeing.

The Dosime radiation meter can measure radiation levels up to 100 R/h with a maximum dose of 1000 rem. The range of the measurable energy is 50 keV to 3 MeV. It can detect X-Rays and Gamma (γ) rays, but not Alpha (α) rays and Beta (ß) rays. Unfortunately, they are also sources of harmful ionizing radiation.

The Dosime device seamlessly connects to smartphones via WiFi and Bluetooth Low Energy (BLE). It comes with a built-in rechargeable battery and an AC/DC module. The battery lasts for about one week on a single charge. At home you can dock it in the charger, giving it access to the Wi-Fi network. The app for this device runs on iOS 9 or later, or Android KitKat 4.4 or later.

The Dosime device is available for purchase at a price of US $249.00 (+ $4.81 shipping). You can order it at Amazon.

DIY Generic Curve Tracer

Stoneslice has shared a Curve Tracer tutorial on Youtube that uses an X Y mode Oscilloscope to test components and their characteristics. Using the on-board Phase Shift Oscillator to provide the test signal, passive and active parts can be tested.

These are the  components needed to build the project:

  • 1 x NPN Switching Transistor
  • 1 x 1K Resistor
  • 1 x 4.7K Resistor
  • 1 x 8.2K Resistor
  • 2 x 10K Resistor
  • 1 x 2M Resistor
  • 3 x 4.7nF Capacitor
  • 1 x 1uF Electrolytic Capacitor
  • 1 x DPDT Switch
  • 4 x Sockets
  • 4 x Test points

In this video Stoneslice demonstrates the project sharing all the technical details and information needed, check it out:

Inspired by Stoneslice’s tutorial, Paul Gallagher (tardate) has developed further on the Curve Tracer by using a simple DC Powered oscillator to drive a test signal across the device under test, instead of relying on an AC power supply. Paul also added a DPDT switch to toggle and compare two devices under test.

X-Y signals are plotted on an oscilloscope to visualise the characteristic curve for the component.

  • X is the ground-referenced voltage at the anode of the device under test (DUT)
  • Y is the voltage across the resistor at the cathode of the DUT, which is proportional to the current flowing through the DUT.

Paul tested multiple components like resistors, diodes and capacitors demonstrating the charging and discharging cycles.

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Below is the schematics of Paul’s circuit.

Paul has launched LittleArduinoProjects series, a collection of electronics projects often involving an Arduino,  and this project’s number is 245! Check his two technical blogs: LittleArduinoProjects, and LittleCodingKata – where he tests tools and talks about software development topics.

Further details about this Curve Tracer are available at Github, where you can find schematic, detailed tutorials, the project snapshots in action and resources.

LASER TRIGGER FOR CHRONOGRAPH

I finished this laser wall trigger for my HIGH RESOLUTION AND ACCURACY CHRONOGRAPH. The purpose of this device is to generate the trigger start and stop impulses for my chronograph as soon as an object disrupts any of the laser beams.

LASER TRIGGER FOR CHRONOGRAPH – [Link]

Redefining a new state-of-the-art in microampere current-sense amplifiers

Silicon Lab’s TS1100 and TS1101 current sense amplifier’s features discussed in this app note.

Sensing and controlling supply current flow are a fundamental requirement in most all electronic systems from battery-operated, portable equipment to mobile or fixed-platform power management and dc motor control. High-side current-sense amplifiers (or “CSAs”) are useful in these applications especially where power consumption is an important design parameter. New CSA developments offer even greater benefits in allowing engineers to save power without sacrificing performance.

Redefining a new state-of-the-art in microampere current-sense amplifiers – [Link]

PIC SD CARD DATA LOGGER

Some time ago I decoded to make a simple general purpose Data Logger with the following parameters for the project.

  • it should have very simple design that should be doable by most amateurs
  • the Data Logger should write the data in a SD memory card in simple text files
  • minimum 2 ADC channels
  • simple to use and simple settings
  • energy efficient
  • low cost

PIC SD CARD DATA LOGGER – [Link]

IkaScope – a new wireless oscilloscope probe

ikalogic.com launched “IkaScope” a new wireless oscilloscope probe that is able to make measurements directly on your mobile phone or your laptop. IkaScope transfers measured signals over high speed wifi connection and it will remember your home or office access points. It will work with iOS, Android and Windows devices (OSx will also be supported).

Specifications

  • Input range 10 mV/div. → 10 V/divMaximum input voltage 80 Vpp
  • Bandwidth 25 MHz
  • Timebase 100 ns/div → 10 s/div
  • Input impedance 1MΩ
  • Input Coupling AC, DC, GND
  • Trigger Rising or falling slopes
  • Digital specifications
  • Sampling rate 200 MSPS
  • Resolution 8-bits
  • Buffer 4K pts (4 * 1K Pts)1

IkaScope is a wireless oscilloscope probe, all contained in an ergonomic stylus. It uses a wifi connection to transfer signals to be displayed on any connected screen (Laptop, Smart-phone, Tablet or Desktop Computer). It’s equipped with a battery that can be recharged via any USB port. Being battery operated, IkaScope always provides 4000V+ galvanic isolation from power mains (even when being recharged).

IkaScope – a new wireless oscilloscope probe – [Link]

Radioactivity detection using very simple ionization chamber

Robert Gawron tipped us with his latest build. He writes:

Today I will show a very simple ionization chamber that can detect radioactivity. I was able to detect with it ionizing radiation from a smoke detector (Am241 isotope). It’s also immune to electromagnetic interference (EMI) due to a good shielding.

Radioactivity detection using very simple ionization chamber – [Link]