DIY the latching reed switch

Thread Starter

hilologic

Joined Oct 27, 2016
15
Hello,
I want to made a latching reed switch, but many time I tried the result not consistence. I do not have the tutorial.
Please share how to made latching reed switch.
regards

sony
 

Thread Starter

hilologic

Joined Oct 27, 2016
15
Thank,
I follow the picture from reed switch manufacturer.
setting latching.png test_Latch.jpg
after I test it is very difficult make latching position.
 

DickCappels

Joined Aug 21, 2008
10,120
If a suggestion is permitted, find a magnet that will close a reed switch with a coil around it. Position the magneto to just before the point the switch closes.

When the coil is energized the switch will close (if you have enough turns and amps in the coil). The switch should remain closed after the current is removed. If it does not stay latched then you need to reposition the magnet and try again.

To unlatch the switch, send a reverse current through the coil for a short period, 0.1 second should be enough. If a reverse current pulse does not cause the switch to "unlatch" you should increase the amps and turns and try again, repositioning the magnet if necessary.
 

Thread Starter

hilologic

Joined Oct 27, 2016
15
Hello,
Actually the device is no need a coil, just the magnet polarity to make the latch or unlatch. The small permanent magnet is sticked to reed switch and to operate just give the other magnet to make latch or unlatch.
 

Alec_t

Joined Sep 17, 2013
14,201
The small permanent magnet is sticked to reed switch and to operate just give the other magnet to make latch or unlatch.
So, does the stuck-on magnet keep the reed contacts closed when the other magnet is removed?
Are you having difficulty keeping them closed or making them open?
 

Thread Starter

hilologic

Joined Oct 27, 2016
15
Lets say, the reed in vertically position and then a permanent magnet move passing from top to bottom the contact state is latching ON. Vice versa if a permanent magnet move passing from bottom to top the contact state is keep OFF. The example application used for level control, the switch condition still run even though have power failure.
 
I'm interested in this as well, as I'm trying to make something similar (the few I've found commercially available are pricey). I agree that a coil isn't needed. The concept of a bistable reed switch is that when it is closed (say via N magnetic field), it stays closed until it encounters a S magnetic field, after which is stays open until it again encounters a N magnetic field.

@hilologic - I think part of the issue in what you have in your image is that the magnet is immediately on the switch, so I assume that it probably stays in whatever position the magnetic field gives it naturally.

There are some good details starting on page 3 of this document: https://standexelectronics.com/wp-content/uploads/ReedSwitchNoOrLowPowerSolution-0209.pdf

This appears to be a latching (Form E) switch:

http://www.mouser.com/ProductDetail/Standex-Electronics/KSK-1E66-1-BV14501/
 
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