Method for multiple objects detection on a capacitive touchpad

A multiple objects detection method for a capacitive touchpad, comprising:.

• verifying at least two objects touch the touchpad;
• detecting sensed value on the touchpad and getting at least a first peak value and a second peak value;
• and
• calculating the change of the sensed value when at least one value of the first and second peak value is smaller than a critical value;
• wherein if the first or second peak value which is smaller than the critical value keeps a decreasing trend within a preset time, it means at least one object of the at least two objects leaves the touchpad.

A multiple objects detection method for capacitive touchpad, comprising:

• verifying at least two objects touching the touchpad;
• calculating object number touching the touchpad;
• calculating touching time of the at least two objects touching the touchpad;
• if the touching time is smaller than a first preset time, verify all object have left the touchpad;
• calculating the leaving time of all the objects leaving the touchpad;
• and
• if the leaving time is greater than a first and a second preset time, send out a single click signal;
• wherein, the object number on the touchpad remains constant when the touching time is calculated.

A multiple objects detection method for capacitive touchpad, comprising:

• verifying at least two objects touching the touchpad;
• calculating object number touching the touchpad;
• calculating the first touching time of the at least two objects touching the touchpad;
• if the first touching time is smaller than a first preset time, verify the at least two objects have left the touchpad;
• calculating the leaving time of the at least two objects leaving the touchpad;
• and
• if the leaving time is smaller than a second preset time, then verify at least two objects touch the touchpad;
• calculating the second touching time of the at least two objects touching the touchpad;
• if the second touching time is smaller than a third preset time, verify the at least two objects have left the touchpad;
• and
• send out a double click signal;
• wherein, the object number touching the touchpad remains constant when the first and second touching time are calculated.

A multiple objects detection method for capacitive touchpad, comprising:

• verifying at least two objects touching the touchpad;
• calculating object number touching the touchpad;
• calculating the touching time of the at least two objects touching the touchpad;
• if the first touching time is larger than a first preset time, verify at least one object of the at least two objects has left the touchpad;
• calculating object number left on the touchpad;
• and
• sending out a dragging signal;
• wherein the object number left on the touchpad remains constant when the touching time is calculated, and after at least one object leaves the touchpad, the object number left on the touchpad must be greater than 1.