Op Amp for magnetic pickup sensor

Hi all,

I was wondering if anyone have experience setting up a magnetic pickup sensor (like the one used in ABS system) to Arduino. Can you recommend an Op Amp for LPF design to reduce noise from the sensor signal? I was looking at MCP6001 or LM318.

I am trying to see if I can work with the analog input instead of using IC like LM339 to convert it to square pulses.

Thanks in advance

I always use LM339 and a circuit like this:

.

Oh I didn't realize that at first. Thank you

fireman613:
Hi all,

I was wondering if anyone have experience setting up a magnetic pickup sensor (like the one used in ABS system) to Arduino. Can you recommend an Op Amp for LPF design to reduce noise from the sensor signal? I was looking at MCP6001 or LM318.

I am trying to see if I can work with the analog input instead of using IC like LM339 to convert it to square pulses.

Thanks in advance

How much noise are we worried about? If you are low-pass filtering that will reduce noise, but most
opamps are low enough noise unless you are building a sensitive microphone amplifier, in which case
something like 4nV/sqrt(Hz) is state of the art (see datasheet for AD8656 for a good example of
a modern low noise opamp)

Depending on just what the output of the pickup is, I would consider putting a couple of diodes across the pickup in parallel but opposite directions to clamp the output of the pickup to about 0.7v or so. The drawing Larry shows has the potential of damaging the input to the op-amp if the pulse is too big. That looks like something right out of the National Semiconductor manuals for the LM339 family stuff (still have those books around too!!)