Society of Robots - Robot Forum

Mechanics and Construction => Mechanics and Construction => Topic started by: srodden1 on October 07, 2010, 08:01:40 PM

Title: looking for a type of switch
Post by: srodden1 on October 07, 2010, 08:01:40 PM
I need to build or buy a switch that reacts with pressure. As in the harder its pressed (not sure of the actual toggle so thats non-important) the more power it lets through.
any ideas?
thanks.
Title: Re: looking for a type of switch
Post by: rbtying on October 08, 2010, 12:31:33 AM
If you've got a microcontroller, a force sensor may be what you're looking for:
     http://www.sparkfun.com/commerce/product_info.php?products_id=9375 (http://www.sparkfun.com/commerce/product_info.php?products_id=9375)

Otherwise, you can set up a comparator with a similar resistor, but it's more work to handle.

What's the purpose of this exercise?
Title: Re: looking for a type of switch
Post by: srodden1 on October 08, 2010, 09:38:39 AM
Im looking to build a hand at first, and to control that hand i will build a controller that would wrap around my hand and thats where the pressure switches come in. 
Title: Re: looking for a type of switch
Post by: rbtying on October 08, 2010, 02:46:48 PM
Use these: http://www.sparkfun.com/commerce/product_info.php?products_id=8606 (http://www.sparkfun.com/commerce/product_info.php?products_id=8606)
Title: Re: looking for a type of switch
Post by: Soeren on October 08, 2010, 10:10:11 PM
Hi,

A cheap method is to get some conductive foam of the type used for some ESD sensitive components.
Sandwich a piece of this between to pieces of PCB-material or thin copper (or brass) plate and solder a wire to each. The resistance of the combo will decrease when the two plates are squeezed together.
It might not be as accurately repetitive as force sensors, but you can't beat the price and for initial experiments, it should do fine.