Protective circuit for an apparatus

1. A method of controlling an apparatus, comprising the steps of:

a) periodically reading values from an accelerometer, wherein the values include a first gravitational value in a first direction and a second gravitational value in a second direction being substantially perpendicular to the first direction;

b) comparing the first and second gravitational values with previous first and second gravitational values;

c) incrementing a no motion counter when the first and second gravitational values are substantially the same as the previous first and second gravitational values;

d) resetting the no motion counter to zero when the first and second gravitational values are substantially different from the previous first and second gravitational values;

e) determining if the no motion counter exceeds a threshold;

f) if yes in e), determining whether the first and second gravitational values are within a tolerance difference from reference first and second gravitational values indicative of a known dangerous orientation; and

g) if yes in f), sending a signal to turn off power delivery to a load of the apparatus.

2. The method of claim 1 , wherein the tolerance difference is less than a 10 percent difference.

3. The method of claim 1 , wherein the apparatus is selected from the group consisting of an electric iron, an electric soldering iron, and an electric heater.

4. The method of claim 1 , wherein the apparatus is an electric iron having a toe, a heel, a first side and a second side, and a heating surface and wherein the known dangerous orientation comprises the heating surface of the electric iron being positioned on a support surface.

5. The method of claim 1 , wherein the apparatus is an electric iron having a toe, a heel, a first side and a second side, and a heating surface and wherein the known dangerous orientation comprises either the first side or the second side of the electric iron being positioned on a support surface.

6. A protective circuit for an apparatus, comprising:

an accelerometer having an output;

a microcontroller coupled to the output of the accelerometer;

a switch configured to control delivery of power to the apparatus, said switch coupled to an output of the microcontroller;

a load of the apparatus coupled to a first terminal of the switch, wherein a second terminal of the switch is configured to be coupled to a power source;

wherein the microcontroller is configured to:

a) receive from the accelerometer a first gravitational value in a first direction and a second gravitational value in a second direction being substantially perpendicular to the first direction;

b) compare the first and second gravitational values with previous first and second gravitational values;

c) increment a no motion counter when the first and second gravitational values are substantially the same as the previous first and second gravitational values;

d) reset the no motion counter to zero when the first and second gravitational values are substantially different from the previous first and second gravitational values;

e) determine if the no motion counter exceeds a threshold;

f) if yes in e), determine whether the first and second gravitational values are within a tolerance difference from reference first and second gravitational values indicative of a known dangerous orientation; and

g) if yes in f), control the switch to turn off power delivery to the load.

7. The circuit of claim 6 , wherein the accelerometer is a two-axis MEMS accelerometer.

8. The circuit of claim 6 , wherein the accelerometer is a three-axis MEMS accelerometer.

9. The circuit of claim 6 , wherein the tolerance difference is less than a 10 percent difference.

10. The circuit of claim 6 , wherein the apparatus is selected from the group consisting of an electric iron, an electric soldering iron, and an electric heater.

11. The circuit of claim 6 , wherein the apparatus is an electric iron having a toe, a heel, a first side and a second side, and a heating surface and wherein the known dangerous orientation comprises the heating surface of the electric iron being positioned on a support surface.

12. The circuit of claim 6 , wherein the apparatus is an electric iron having a toe, a heel, a first side and a second side, and a heating surface and wherein the known dangerous orientation comprises either the first side or the second side of the electric iron being positioned on a support surface.