Maker Pro
Maker Pro

Keyless and contactless Reset switch

shakey1961

Apr 15, 2017
10
Joined
Apr 15, 2017
Messages
10
Hi. I need / would like, to be able to momentarily interrupt a 12v line to reset a remote control / wireless switch.

I have come up with the idea of using a NC reed switch then applying a magnet to disconnect it.

It is going in a car and the reed / reset switch will be behind a plastic panel.

Is this simple enough or is there anything else I should think of?

I'm also looking for a keyring that is a magnet that I can touch on the panel to operate the reed switch.

Any ideas?

Many Thanks
 

Harald Kapp

Moderator
Moderator
Nov 17, 2011
12,615
Joined
Nov 17, 2011
Messages
12,615
Reed switch + magnet sounds good, provided the magnet is strong enough to operate the reed switch behind the panel.
 

Alec_t

Jul 7, 2015
3,212
Joined
Jul 7, 2015
Messages
3,212
..... and provided the reed switch is able to handle making/breaking a high enough DC current when supplying a load which could be resistive/capacitive/inductive.
 

shakey1961

Apr 15, 2017
10
Joined
Apr 15, 2017
Messages
10
..... and provided the reed switch is able to handle making/breaking a high enough DC current when supplying a load which could be resistive/capacitive/inductive.
It's supplying a remote wireless switch which in turn is feeding two small power supplies for two dash cams. I don't think's there's a lot of current involved
 

ChosunOne

Jun 20, 2010
453
Joined
Jun 20, 2010
Messages
453
Be aware that if you're going to carry a strong magnet on your person, you need to keep it well away from any credit-type cards that still use a magnetic strip---a magnet will scramble and render that magnet strip unreadable. Also, take care not to hold it against any wrist/pocket watch with mechanical movement.

I use a concealed reed switch to trigger a garage door open/closed, and keep a magnet conveniently stuck out of sight on a piece of nearby steel. That way, it's always handy and those who know about it (members of the household) always have it handy. Consider keeping the magnet somewhere you can reach it easily from your seat.
 

AnalogKid

Jun 10, 2015
2,665
Joined
Jun 10, 2015
Messages
2,665
I use a concealed reed switch to trigger a garage door open/closed, and keep a magnet conveniently stuck out of sight on a piece of nearby steel. That way, it's always handy and those who know about it (members of the household) always have it handy.
Stolen.

ak
 

shakey1961

Apr 15, 2017
10
Joined
Apr 15, 2017
Messages
10
Ta Dah.... I think I've found something better. A Hall Effect sensor operating a relay. In it's off state the relay is NC.

Can anyone point me in the right direction for a 12v circuit version?

Thanks
 

Bluejets

Oct 5, 2014
5,883
Joined
Oct 5, 2014
Messages
5,883
Ta Dah.... I think I've found something better. A Hall Effect sensor operating a relay. In it's off state the relay is NC.

Can anyone point me in the right direction for a 12v circuit version?

Thanks

Most hall effect switches are open collector and will handle voltages well over 12v dc . Don't forget a small filter cap on the supply pins of the hall effect ( around 0.1uf if I remember correctly).

Also note that there are many types of hall effect and you will be looking for one similar to an A1120 which will switch rail to rail.

They can be operated by mounting the magnet on the back side of the ic and presenting a piece of steel to make the switch operate which may overcome some of the problems mentioned above. You will have to play with magnet strength to overcome the distance between ic and " key". If you use the rare earth magnets off Ebay you can stack them together. I have used 3 mm x 1mm for ignition systems.

Stolen............ Good one
 
Last edited:
Top