Recently, [Solder Hub] put together a brief video that demonstrates the basics of a Hall Effect sensor — in this case, one salvaged from an old CPU fan. Two LEDs, a 100 ohm resistor, and a 3.7 volt battery are soldered onto a four pin Hall effect sensor which can toggle one of two lights in response to the polarity of a nearby magnet.
If you’re interested in the physics, the once sentence version goes something like this: the Hall Effect is the production of a potential difference, across an electrical conductor, that is transverse to an electric current in the conductor and to an applied magnetic field perpendicular to the current. Get your head around that!
Of course we’ve covered the Hall effect here on Hackaday before, indeed, our search returned more than 1,000 results! You can stick your toe in with posts such as A Simple 6DOF Hall Effect ‘Space’ Mouse and Tracing In 2D And 3D With Hall Effect Sensors.
Cool, another video of showing how a component works… no hack… C’mon, hackaday is so much better than this. A few days ago, how to use an EEPROM, now this?
What’s next, a tutorial about how to connect a resistor. Did you know you can connect them just how you like, no polarity issues… it’s amazing!
In order to start hacking, one first has to learn how the building blocks work.
Not everyone here is a pro or EE major.
While I can do more complicated projects, I also enjoy building small little gizmo’s like this occasionally. I was already wondering if I have one of these in my parts bin.
And I saw at least one small but useful hack: extend component leads to reuse an existing component.
This is a good example of how not to use an 18650. It wouldn’t take much to short the positive wire to anywhere on the exposed case and give yourself a bad day.
Heatshrink is cheap.
Also, soldering wires directly to the cell is a no-no.
Wikipedia says exactly the same thing!
It always gets me how the Hall effect has developed since its discovery.
The first experiments that proved its existence took a lab full of expensive equipment, expensive materials, and a bunch for folks in lab jackets all working together to make it work. From that, we’ve gone to a dinky little three pin gizmo that works reliably, every time, with no more fuss than a light switch. You’ve got Hall effect sensors that can provide an off/on signal for magnet/no magnet or sensors that can provide an analog output voltage proportional to the current flowing in a nearby wire. I’ve got an go-kart accelerator pedal that provides a 0-5V analog signal proportional to the distance the pedal is pressed. It uses a magnet on the pedal and a Hall effect sensor to detect the travel distance.