Here is a small collection of circuits that provide an interface to sensor transducers including pressure, temperature, and others.
This circuit provides a highly integrated analog sensor signal conditioner targeted for automotive applications. The device provides amplification, calibration, and temperature compensation. Output is digital. Read the rest of this entry »
Christian Aurich wanted a way to measure current on PCBs without having to cut the traces. He concluded building a probe able to measure current using a Hall Effect sensor. It’s on prototyping phase, so improvements are yet to come. He writes:
In the last weeks I followed an idea to measure current without the need to cut the wires or even open a pcb trace. The solution i came up with is a hall effect based measurement.
I wrote some more about it in an article here: http://avrs-at-leipzig.de/dokuwiki/en/prokekte/fluxprobe
Building a current / flux probe for contactless measurements - [Link]
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..
UGN3503U hall effect sensor – Gauss Meter - [Link]
Ivan Sergeev writes:
The Wireless Power Meter is a simplistic ATmega88p and ZigBee/XBee based true V-I power meter. AC voltage measurement is made from the rectified signal of a step-down transformer, and current measurement is made with the pass-through Allegro ACS712 Hall-Effect sensor.
Wireless Power Meter - [Link]
Ivan Sergeev writes:
The battery-powered Levitating Digital Scale electromagnetically levitates a load platform, and uses a linear hall-effect sensor to measure the magnetic field strength to determine the weight of the platform. The levitating platform is embedded with a permanent magnet that opposes the magnetic field of a solenoid (the electromagnet). When a load is placed on the platform, the levitating platform will settle to a new height. Since the magnetic field created by the electromagnet is held constant, the linear hall-effect sensor experiences a stronger magnetic field due to the closer permanent magnet platform. Therefore, the reading on the linear hall-effect sensor increases, and can be correlated with the added weight on the scale.
Levitating Digital Scale - [Link]
I’ve been meaning to make something cool for my dorm room this coming semester and decided that some custom closet lights would look great. In this Instructable, I’ll show you how to make some nice-looking LED lights that will turn on automatically using a hall effect sensor and a magnet.
Edit: I’ve noticed a lot of people are hating on the excessive control used in this project so I just wanted to clarify a few things:
- This instructable was also meant to be a lite introduction to actual AVR programming for those people who are used to only Arduino programming. I had a bit of trouble finding useful information when I was learning so I figured it would be nice to help out some others. That is why I posted the basic tutorials along with my AVR code.
- Yes I’m aware I could have simply used a reed switch to switch the LEDs when the door opened and closed. I wanted to leave room open for myself to add different light modes, maybe using more wires and pins to create nice fading effects, possibly a remote control sensor, and maybe even an auto-shutoff routine.
Door Activated LED Lighting using Hall Effect Sensors - [Link]
The ACS712 is a fully integrated, hall effect based, linear current sensor. It converts the current that passes through its input pins to a proportional voltage on an output pin. He connected the output pin to an analog pin of his Arduino, and made a simple logging software that reads 1000 samples.
Current sensing with the Arduino - [Link]
At Adaptive Path’s San Francisco studio, we had a fussy refrigerator that wouldn’t always latch when it was shut. Sometimes the fridge would sit open for hours, spoiling food and wasting all the unicorn tears and panda fur oil, before someone would discover it had been left open.
Like any good tinkerers we fixed the problem with technology, devising an alarm that would let us know when the fridge had been left open for too long. Whenever the pleasant sound of the 80s echoed through the office, we knew the fridge needed our attention.
Adaptive Path Fridge Alarm – [Link]
Howard Matthews wanted a new speedometer for his Landrover so he build one replacement speedo. The unit runs off an Atmega328 and it is using smd components on it’s two board design. The speed is measured using an Hall Effect sensor which gets triggered by a tiny magnet stuck to the propshaft. The time between the pulses is inversely proportional to the speed you’re going.
New speedo for the Landrover – [Link]