Hall Effect Sensors and Ceramic Magnets

[Noah]

I'm building a device to measure the RPM of a wheel, and I'm using a hall effect sensor and a magnet. I have my sensor hooked up to a 5V supply on the supply pin, ground on the ground pin, and my multimeter on the output pin. I powered up the supply and moved a 1/2" ceramic magnet by the front of the sensor, and saw a very minimal (.01V to .03V) change. I haven't used hall effect sensors before so I'm not quite sure if I'm doing it correctly. Do I need an earth magnet, or perhaps a neodymium? Or does the current through it change and level off so fast that I'm getting a minimal dc voltage change? I'd check but I dont have an Oscope. Any help would be greatly appreciated.

Oh and here is the hall-effect sensor I'm using... https://mouser.com/catalog/specsheets/ProductSheet_SS351_451.pdf

 

[Vizier87]

if you want the output as RPM versus Voltage, you can use a freq-to-voltage converter like the LM2917 where the output can be coupled to the IC.

The sensor gives out an output when it senses a N or S pole. Like a comparator conceptually.

 

[schmitt trigger]

The device output is an open collector. You need a resistor from that pin to supply voltage, as shown on figure 4 on the data sheet.

Data sheets are your best friends. Read them thoroughly.

 

[crutschow]

Data sheets are your best friends. Read them thoroughly.

But then the forum would have far fewer questions to answer.

 

[schmitt trigger]

But then the forum would have far fewer questions to answer.

Sad but true.
Data sheets, App notes, App briefs, Eval Board descriptions, any sort of documentation the IC vendor puts out is the best way to learn how a device works.
True, data sheets in particular may be sometimes a little tedious, but hey, this comes with the territory. And they are the only thing that separates you from a miss-applied and non-working circuit.

 

[Noah]

The device output is an open collector. You need a resistor from that pin to supply voltage, as shown on figure 4 on the data sheet.

Data sheets are your best friends. Read them thoroughly.

Ah I see. So since my entire project is being powered by only 5VDC it looks like that limits me to the first two circuits in diagram 4. And here I thought I could just "plug and play" with the hall effect sensor

 

[crutschow]

Ah I see. So since my entire project is being powered by only 5VDC it looks like that limits me to the first two circuits in diagram 4. And here I thought I could just "plug and play" with the hall effect sensor

"Plug and play (pray)" only works occasionally with PCs, and seldom with ICs.