Hello.
I am currently researching alternative ways to pickup a vibration in a ferromagnetic and/or conductive string, mainly has a thought exercise.
Lastly, I am investigating hall effect sensors for the following two setups after some thought :
The other setup would not use any current but a little (1.5 mm OD) neodymium magnet bead/toroid passing the cable in proximity to the sensors. It would probably dampen vibration a little but would probablybe easier to build and with way larger output at the sensor.
I am currently researching alternative ways to pickup a vibration in a ferromagnetic and/or conductive string, mainly has a thought exercise.
Lastly, I am investigating hall effect sensors for the following two setups after some thought :
- A guitar string (less conductive but with better vibrational/strength characteristics) with 0.5mm diameter would be subject to a fairly large DC current. under low voltage. (1A to 5A), a couple of volts.
- A pair of Hall effect sensors (3503) would be placed at 4 to 5 mm to the string, perpendicular to the string, at both sides of the string.
- Since the string creates a static magnetic field from the current it passes, the vibration makes the field oscillate. It is picked up by the hall effect sensor
- The magnetic field intensity would be quite low, by using Ampere Law, it would be in the 60 to 100µT range.
- The amplitude of voltage variation range at the hall sensor would be proportional to the string oscillation travel.
- Is the 3503 sensor sensitive enough / low noise enough at the µT range?
- bandwidth is 23 KHz as per datasheet, so audio transcription should be OK ?
- What kind of preamp setup should i use ? I wonder if a phono preamp without RIAA equalization could be ok, I assume delta voltage would be in the µV range.
The other setup would not use any current but a little (1.5 mm OD) neodymium magnet bead/toroid passing the cable in proximity to the sensors. It would probably dampen vibration a little but would probablybe easier to build and with way larger output at the sensor.
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