I have a trolling motor hooked up to a canoe. I need a "dead man's switch" to de-energize the motor if I should fall overboard. This isn't being hooked to the power supply, but rather to a PWM, so current and voltage are low. I have a reed switch, but see a disadvantage: to make it work, I must attach a piece of ferrous metal between it and a magnet, otherwise it won't have enough strength to hold a magnet. By doing this for five hours (or more) at a time, many times, I'm concerned that the metal attached to the magnet will itself become magnetized, thus not breaking contact once the magnet is removed.
One option I'm thinking of is a switch that incorporates a metal rod that, when removed, opens the switch. I had something like this on a model rocket launch control years ago, and it was a bit dodgy. I wonder if better versions of it exist. What would such a switch be called?
Any other ideas? I'm thinking string tied to a knife switch, though this isn't ideal (the switch could close again during capsize).
Thanks.
One option I'm thinking of is a switch that incorporates a metal rod that, when removed, opens the switch. I had something like this on a model rocket launch control years ago, and it was a bit dodgy. I wonder if better versions of it exist. What would such a switch be called?
Any other ideas? I'm thinking string tied to a knife switch, though this isn't ideal (the switch could close again during capsize).
Thanks.