Silly "useless machine"... how much torque do i need?

[Jack.Straw]

Hello. I started making one of those useless machines (leave me alone box?) but my box is pretty tiny. The inside usable area is 3" long x 2" wide x 2" tall, so i need a motor that will fit in that space along with a couple batteries, a small switch, and the arm. I've found several that would work as far as size goes, but am unsure on the amount of torque i will need. The toggle switch that the arm will need to push is Radio Shack part 275-636. The arm will be made of 1/4" wood, as will the door that it needs push open before hitting the switch. This is a to-scale representation using **broken link removed**:

Of course that does not show the inside switch, batteries, or anything else. The specs on that motor show 11.00 in*oz torque at 3 volts. Do you think that is enough to do the job? If not, how much torque would you guess is needed to do the job? I know that's probably hard to say considering i can't really tell you how hard it is to move the toggle, what kind of hinge i am using, or how heavy the arm is... but any advice you can offer would be appreciated!

Such a fun waste of time
-Scott

 

[srizbf]

toggle switch that you use , require very large force to throw it on one side and the same for the other.

you must first know the reqd force for the switch you likely use .
then only you can say whether the motor is suitable or not.

 

[Jack.Straw]

Thanks for the responose... is the required force something i can find on the spec sheet or from the manufacturer?

 

[Frivolous Engineering Co.]

Sounds like your motor may not have enough torque. I've modded several servos into gear-motors to be used in useless machine and the specs on them were around 3-5 Kg/cM.

The motor that I'm selling in my Useless kits stall at around 3Lbs/inch.

But, it all depends on how stiff your toggle is, and how long an arm you use (longer arms need more torque). And you can also adjust things by using 2, 3 or 4 batteries. The original design suggested using 4 AA's which in most cases was overkill. It made for a really strong/fast action...too fast in my opinion. By dropping down to 3 or 2 cells, there usually was enough torque to flip the toggle.

The only real way to know is to test things out.