Maker Pro
Maker Pro

Need help finding a weight sensing on/off switch? Like in lawn mowers.

ben.wins

Aug 10, 2016
1
Joined
Aug 10, 2016
Messages
1
So I'm working on a project that hinges on a device being turned on when a person sits in a seat, and then off when the stand. What I need it to do is take a 12V power supply and only complete the circuit when a person is seated. Does this kind of sensor have a name or does anyone have any recommendations? It's kind of like a reverse deadman switch, and I think they're called force sensors but I'm having trouble finding one that simply completes the circuit instead of outputting information.
 

Minder

Apr 24, 2015
3,478
Joined
Apr 24, 2015
Messages
3,478
You wouldn't want to go to the extent of a load cell for that operation, unless you wanted to weigh the person.
I would use a either a simple reed switch and magnet to detect when a weight is placed on the seat, or a small prox switch such as Honeywell SS400 series and a miniature magnet,
You would need some kind of simple pressure/sense mechanism that physically moves down very slightly when sat on then return up, a small coil spring could do it.
Even a simple limit switch will do the same.
M
 

Alec_t

Jul 7, 2015
3,587
Joined
Jul 7, 2015
Messages
3,587
Welcome to EP!
You're looking for a 'seat occupancy sensor'. But the type used in a car seat is expensive.!
A coil spring (as Minder suggested) or leaf spring, operating a lever-actuated microswitch, would be my choice.
 

Sunnysky

Jul 15, 2016
541
Joined
Jul 15, 2016
Messages
541
If the seat has no springs, this can be a mechanical challenge.
An optical reflector thru hole in the seat might work powered by ignition switch.
 

Herschel Peeler

Feb 21, 2016
401
Joined
Feb 21, 2016
Messages
401
So I'm working on a project that hinges on a device being turned on when a person sits in a seat, and then off when the stand. What I need it to do is take a 12V power supply and only complete the circuit when a person is seated. Does this kind of sensor have a name or does anyone have any recommendations? It's kind of like a reverse deadman switch, and I think they're called force sensors but I'm having trouble finding one that simply completes the circuit instead of outputting information.

http://www.jameco.com/z/1696-Pololu-1-2-Inch-Circular-Force-Sensing-Resistor_2128260.html

Pressure sensitive resistor, distributed by Jameco Electronics. They come in different sizes and shapes. Maybe put a marble on top of it and a piece of cardboard, or something.
 

duke37

Jan 9, 2011
5,364
Joined
Jan 9, 2011
Messages
5,364
Fit a microswitch under the seat with a rod to activate it through a hole in the seat.
 
Top