Magnetic linear fader

1. A linear fader comprising:

a slider that is configured to slide along a rail, wherein the slider comprises a magnet;

a plurality of coils spaced along a length of the rail;

one or more sensors configured to detect a position of the slider along the rail; and

control circuitry operatively coupled to the plurality of coils and the one or more sensors, wherein the control circuitry is configured to:

receive a first location of the slider from at least one of the one or more sensors;

receive a signal corresponding to a desired location of the slider; and

cause a first electrical current to pass through the plurality of coils, thereby generating a force on the slider in a direction toward the desired location,

wherein the control circuitry is further configured to control a second electrical current that passes through the plurality of coils, wherein a magnetic field of the second electrical current through the plurality of coils resists movement of the slider along the rail.

2. The linear fader of claim 1 , wherein the plurality of coils are configured in a three-phase arrangement, and wherein the electrical current is a three-phase electrical current.

3. The linear fader of claim 1 , wherein the control circuitry is further configured to:

receive a second location of the slider from at least one of the one or more sensors; and

transmit, to an external circuit, a signal indicating the second location of the slider.

4. The linear fader of claim 3 , wherein the signal indicating the second location of the slider comprises an indication of a fade effect to be applied to a signal corresponding to the linear fader.

5. The linear fader of claim 1 , wherein the signal corresponding to the desired location comprises a signal attribute, and wherein the control circuitry is further configured to determine the desired location based on the signal attribute.

6. The linear fader of claim 1 , further comprising a knob attached to the slider.

7. The linear fader of claim 6 , further comprising a housing that houses the slider, the plurality of coils, and the one or more sensors.

8. The linear fader of claim 1 , wherein each of the one or more sensors comprises a magnetic sensor configured to detect a magnetic field of the magnet.

9. The linear fader of claim 8 , wherein each magnetic sensor comprises a Hall-effect sensor.

10. The linear fader of claim 1 , wherein the one or more sensors are spaced along at least one side of the rail.

11. The linear fader of claim 1 , wherein a first portion of the plurality of coils is spaced along a first side of the rail, and wherein a second portion of the plurality of coils is spaced along a second side of the rail.

12. The linear fader of claim 11 , wherein a first portion of the electrical current passes through the first portion of the plurality of coils, wherein a second portion of the electrical current passes through the second portion of the plurality of coils, and wherein a force of a first magnetic field generated by the first portion of the electrical current applied to the magnet balances a force of a second magnetic field generated by the second portion of the electrical current applied to the magnet.

13. The linear fader of claim 12 , wherein the magnet comprises a plurality of north poles and a plurality of south poles.

14. The linear fader of claim 1 , wherein the plurality of coils are formed in a printed circuit board.

15. The linear fader of claim 1 , wherein the resistance of movement simulates a desired feel-effect.

16. The linear fader of claim 15 , wherein the control circuitry is further configured to receive a signal indicative of the desired feel-effect, and wherein the control circuitry is configured to control the second electrical current in response to receiving the signal indicative of the desired feel-effect.

17. The linear fader of claim 16 , wherein the desired feel-effect comprises at least one of a coggy feel, a notchy feel, an end-stop feel, or a friction of movement feel.

18. A method comprising:

receiving, from at least one sensor, a location of a slider along a rail, wherein each sensor is configured to sense a magnetic field of the slider;

receiving, from a remote processing circuit, a signal corresponding to a desired location of the slider;

causing a first electrical current to pass through a plurality of coils that are spaced along a length of the rail, wherein the first electrical current generates a magnetic field that applies a force on the slider, and wherein the force on the slider is in a direction toward the desired location; and

controlling a second electrical current that passes through the plurality of coils, wherein a magnetic field of the second electrical current through the plurality of coils resists movement of the slider along the rail.

19. The method of claim 18 , further comprising:

receiving a second location of the slider from at least one sensor; and

transmitting, to the remote circuit, a signal indicating the second location of the slider.

20. The method of claim 18 , wherein causing the first electrical current to pass through the plurality of coils comprises:

causing a first portion of the electrical current to pass through a first portion of the plurality of coils; and

causing a second portion of the electrical current to pass through a second portion of the plurality of coils, and

wherein a force of a first magnetic field generated by the first portion of the electrical current applied to the magnet balances a force of a second magnetic field generated by the second portion of the electrical current applied to the magnet.