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Physicists from the University of Utah have developed an inexpensive, highly accurate magnetic field sensor of a new kind. The new magnetic-resonance magnetometer resists heat and degradation, works at room temperature and never needs to be calibrated. A disadvantage of the sensor is that it is slow, taking up to a few seconds to detect a magnetic field.
The sensor is based on an organic semiconductor polymer named MEH-PPV which is really nothing more than a dirt-cheap orange-colored electrically conducting, magnetic field-sensing plastic paint. Only a drop of it can be used to measure magnetic fields highly accurately, which costs just as little as drop of regular paint. The sensors make use of spintronics, in which data is stored both in the electrical charge of atomic nuclei and in what is known as the “spin” of those subatomic particles. Described simply, spin makes a particle behave like a tiny bar magnet that is pointed up or down within an electron or a nucleus. [via]
A ‘Dirt Cheap’ Magnetic Field Sensor from ‘Plastic Paint’ - [Link]
thebackshed.com writes:
This little project is a Gauss Meter, or Flux Meter, or Magnet Polarity Indicator. Basically, it senses magnetic fields. Using a hall sensor, the meter can measure the Gauss/Flux density and polarity of a magnet. It only needs a few parts, so can be built without a circuit board.
A Gauss Meter is handy when you want to know what end of a magnet is a North or South pole, and when you want to test magnets for strength, especially if they may have been heat damaged.
The heart of the meter is a UGN3503U or similar hall sensor. The UGN3503U is a linear hall sensor, meaning its output level changes with magnet Gauss changes, and the device can be sourced from most electronics suppliers, like Jaycar, Altronics, Farnell, etc..
Gauss Meter - [Link]
Here’s an article that presents a rather innovative look at how to spoof magnetic card readers. The spoofer uses an atmega168 connected up to an electromagnet. The article has the source code, hardware schematic and action shots, don’t miss it! [via]
Magnetic Card Spoofer - [Link]
Baolab Microsystems has developed innovative, pure CMOS MEMS devices that use Lorentz force sensors to detect the strength and direction of the Earth’s magnetic field. The new 3D Digital NanoCompass™ technology matches existing performance benchmarks for sensitivity, power consumption and package size at dramatically lower cost. An additional unique feature is autocalibration for consistent accuracy.
The new compass chips utilise Baolab’s NanoEMS™ technology, which allows nanoscale MEMS devices to be fabricated using standard high-volume CMOS lines and fully integrated monolithically with analogue and digital electronics. The MEMS elements are defined within the existing metal interconnect layers on the wafer as part of the normal CMOS production process. Conventional 3D compass devices typically use magnetoresistive materials or Hall-effect devices combined with magnetic field concentrators to detect the direction of the Earth’s magnetic field. [via]
Novel 3D digital MEMS compass fabricated in CMOS - [Link]
bobdavis321.blogspot.com writes:
Back in 2000 I wrote an article for Nuts&Volts magazine about predicting earthquakes via a electromagnetic monitor. Back then the EM sensor rotated through 180 degrees taking readings as it went. That was because EM sensors were expensive. Today they are cheap and I am working on a new device that uses 8 sensors in a circle. I am not sure If I should read them or take their difference and read that?
Predicting Earthquakes via Magnetic Field Monitors – [Link]
This project shows how to make a magstripe card spoofer. This project is build from “Craig” @ Flashing LEDs blog and the device is able to simulate the card being swiped. He has also build a professional made circuit board to complete the project and system is powered form a 9V battery. [via]
Homebrew magnetic swipe card emulator - [Link]
I’m very proud to announce a new board, designed and developed by the RepRap Research Foundation. Its called the Magnetic Rotary Encoder, and it uses a magnet to provide positional feedback information. It is based around the AS5040 chip, and provides 10-bits of resolution per rotation (1024 different positions!) It has 5 different output modes, a 6.1mm hole that fits the magnet for easy aligning, plenty of diagnostic LEDs for coolness, and 6 different mounting holes for ease of use, including GM3 gearmotor mounting holes.
Magnetic Rotary Encoder v1.0 – [Link]
NedLog writes:The HandySwipe provides a portable magnetic card reader interface and display. It collects card data from a “Type 2″ card reader (shown here), and displays the data on a small character LCD screen. Type 2 stripes are by far the most common in use, such as on credit cards and drivers’ licenses. The device can store up to 50 cards, runs on four AA’s, and has a serial connection to download its memory to your computer in CSV format. It can also download data in a raw bistream format compatable with StripeSnoop, so you can take advantage of StripeSnoop’s powerful parsing and analysis features. [via]
HandySwipe portable magnetic card reader - [Link]
This is a high resolution flux gate magnetometer based on the FGM-3h sensor.It is used to measuring variations in earth’s magnetic field.This project FGM-3h-sensor manufactured by Speake & Co. This sensor is a very sensitive flux gate magnetometer capable of a resolution in the nT range.it is so sensitive that it can not be used in north-south direction since the magnetic field of the earth is too strong in this direction. [via]
High resolution flux gate magnetometer - [Link]
