Is there a magnetic switch (like a reed switch) but with no moving parts?
I need a switch that can be turned on by a magnetic field but won't move around due to tremendous shock absorption.
Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. It only takes a minute to sign up.Sign up to join this community
Yes. Search for 'hall effect' switches.
Figure 1. Hall-effect sensor.
The Hall effect is the production of a voltage difference (the Hall voltage) across an electrical conductor, transverse to an electric current in the conductor and a magnetic field perpendicular to the current. It was discovered by Edwin Hall in 1879.
Hall effect on Wikipedia.
Figure 2. Hall sensor available from Sparkfun for < $1.
Analog sensors are available with built-in electronics to amplify the small signal generated by the hall-effect to a more useful level, typically 0 to 5 V or 0 to 10 V. The output voltage will then be a function of the magnetic field strength - typically determined by the proximity of the magnet.
Digital sensors are available with built-in electronics to amplify the hall-effect signal and turn on a digital output when the level exceeds a specified magnetic field strength. Usually a little hysteresis is employed so the field strength has to fall a bit before the switch turns off. This prevents rapid switching when the field strength is just on the threshold.
The Sparkfun device listed above has an 'open-collector' output to interface to your micro. This will require a pull-up resistor. Ask if you need help with this.
Read OP and @davidcary's comments below on latching types. I was not aware of these and hadn't read the details on the Sparkfun device I linked to. I learn too!