Does anyone have any experience using inductors as input sensors for an Arduino?
Many, many years ago . . . no doubt back when Hobbits lived in middle earth; Radio Shack published a great little series of books for electronic experimenters called, Engineer's Mini-Notebooks that were written by Forest M. Mims II who is a prolific writer on hobby electronics.
One of the most interesting projects (the Science Experiments book) was a simple seismograph that used a magnet suspended over a telephone pickup as a sensor for a small circuit comprised of two 741 op-amps running on a +9/-9 power supply. I built this device sometime ago and had very interesting results with it.
Although I could use an Arduino to measure, the output signal (0-14 VDC) from the seismograph as I still have the original circuit. I would like to rebuild the device from the ground up, using an Arduino for both processing the incoming signal from the inductive sensor and the Analog-to-Digital-Converter (ADC).
This would help to better utilize the Arduino's capabilities than just using it as an ADC interface between the seismograph and a PC .
However, I am a little cautious about simply attaching the inductive pick-up to the Arduino's analogue inputs.
I had thought about using the inductor with a capacitor to create a tank circuit, but am not sure if that is the correct route to take. Another possibility might be to use the inductor in an R/C network to adjust the frequency of a 555-based oscillator, but once again, this adds complexity to the exercise.
So does anyone have any suggestions on how to use a variable inductive coil as a sensor for an Arduino?