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Hall effect sensor sensitivity


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Just had the delivery of a simple hall effect sensor with three legs, it is from DealExtreme and come mounted on a simple board.

 

I just cant figure out how to read the output. From the info on dx site it should give reading in terms of voltage. The pin that is supposed to be output reading give a constant 0.6 v.

 

Is my magnet not strong enough? I tried all possible position and the result is the same 0.6v. The absence of any other chip on the board looks to me there is no higher level protocol to read the measurement..

http://www.dealextreme.com/p/hall-magne ... -5v-135033

 

Thanks in advance :)

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can you see a part number on that device? if so you might be able to get the datasheet, and see what the exact specs are. it mah help trying to figure this thing out

I was wondering too. Strange shop that, no link to datasheet or manufacturer part number.

 

Uhm, you give this sensor something to read like moving a magnet in front of it ?

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Thank you all for the help :)

 

The only marking I can barely read is 44E938, and google did not return any useful stuff.

 

Tried to add a 680 ohm and later a 10k ohm resistor from Vcc to the output pin, the voltage read out did change but remained the same when the magnet is put nearby.

 

And I tried almost every position.. funny thing is the resistor got caught :lol:

 

So I can still have hope that this deal is not a total lost? The other laser part in the same order is already declared lost :cry:

 

Thanks again :)

 

post-2970-135135558437_thumb.jpg

 

post-2970-135135558442_thumb.jpg

 

post-2970-135135558446_thumb.jpg

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Google shows that the "44E" sensor should be the same as the 3144 sensor that Rob found. Dealextreme is infamous for changing the design/supplier of things after the initial order runs out. First run or three tend to be great, then they switch, and quality goes down.

 

Anyway, best thing to do is sketch out the schematic of that board first, without that, anything else is pointless. Once you got that figured, it does require atleast 4.5v power voltage. It should be pinned (The sensor atleast, not sure of the connector at the bottom) as V+, Gnd, Output.

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Google shows that the "44E" sensor should be the same as the 3144 sensor that Rob found. Dealextreme is infamous for changing the design/supplier of things after the initial order runs out. First run or three tend to be great, then they switch, and quality goes down.

 

Anyway, best thing to do is sketch out the schematic of that board first, without that, anything else is pointless. Once you got that figured, it does require atleast 4.5v power voltage. It should be pinned (The sensor atleast, not sure of the connector at the bottom) as V+, Gnd, Output.

 

Thanks cde, i'll try this over the weekends. Perhaps just cut the sensor out to play around with :)

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Ok i tried the suggestions here and read the references, decided to connect to the sensor's exposed legs instead of the pins on the board. At one point managed to have some readings through a voltmeter. By that I mean putting a magnet will turn the voltage reading in the reverse direction, and removing it will read the voltage moving in another direction. Repeated couple of times made me feel this is not a coincidence. However it is in terms of mV, which is too small for sensing.

 

Also tried the pull-up/down but unable to read anything (just Vcc or GND in either case). I need to work more on this little thing!

 

Again thanks everyone for your help :)

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Ok I think I got it :)

 

Not sure if I'm doing this right, but I tried resistor after resistor and finally a 220 ohm resistor is giving measurable outputs for magnet present or absent. The legs on the board is not in line with the sensor itself. When looking at the board where you can see the legs of the sensor, the leftmost pin on the board is the signal, centre is the Vcc, and rightmost is the ground. There is an LED on board to indicate correct voltage input. I wired the 220 ohm resistor from the signal to ground pin.

 

5V is provided (actually less than that, the Nano i used to try out this sensor gave smoke last week :o and since then the output voltage from its 5V pin became 4.2-ish if powered from USB). When no magnet the reading is 0.459V. When magnet is present the reading is around 310 to 330mv.

 

Next step will be making this into my first Energia project :)

 

Thank you all of you who helped!

 

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