Active stylus adaptive to multiple input types at an information handling system
An information handling system stylus transmits a wireless signal at a writing tip to enhance touch detection of the writing tip by a touchscreen display and receives wireless signals from the touchscreen display at a receiving antenna. To enhance control of wireless energy distributed at the writing tip, the receiving antenna is selectively coupled to the writing tip, such as by transitioning from a float of the receiving antenna to an interface with the stylus power source at transmit by the writing tip. Charge at the receiving antenna helps to shape the energy distribution from the writing tip, such as to match the energy distribution of other styluses in use at the touchscreen display.
1. An information handling system comprising:
a housing;
a processor disposed in the housing and operable to execute instructions that process information;
a memory disposed in the housing and interfaced with the processor, the memory operable to store the instructions and information;
a touchscreen display disposed in the housing and interfaced with the processor, the touchscreen display operable to present the information as visual images and to detect touches as inputs;
a touch controller interfaced with the touchscreen display and operable to locate touches on the touchscreen display and to transmit wireless signals from the touchscreen display; and
a stylus having a body, the body supporting a writing tip configured to transmit wireless signals, a receive antenna separate from the writing tip and configured to receive wireless signals, a processing resource interfaced with the writing tip and the receive antenna, and a power source operable to power the processing resource; and
a non-transient memory disposed in the stylus body and interfaced with the processing resource, the non-transient memory storing instructions that when executed on the processing resource cause:
the receive antenna to float relative to the power source when the receive antenna receives wireless signals transmitted from the touchscreen display, the float relative to the power source comprising decoupling from the power source; and
the receive antenna to couple relative to the power source when the writing tip transmits wireless signals to the touchscreen display.
2. The information handling system of claim 1 further comprising:
a capacitor disposed between the processing resource and the receive antenna;
a direct current voltage source interfaced with the power source and coupled between the capacitor and the receive antenna; and
instructions stored in the non-transitory memory that when executed on the processing resource apply a direct current voltage at the receive antenna to achieve a desired wireless signal transmit distribution at the writing tip.
3. The information handling system of claim 2 wherein the touch controller communicates by wireless signals a selectable direct current to apply to the receive antenna during transmits of wireless signals from the writing tip.
4. The information handling system of claim 1 further comprising non-transient memory disposed in the housing and storing instructions that when executed cause the touch controller to detect plural styluses interacting with the touchscreen display and to command at least one of the plural styluses to couple the receive antenna to the power source to achieve a desired wireless signal transmit distribution at the writing tip.
5. The information handling system of claim 4 wherein the instructions include calibration of the type of coupling of the receive antenna to the power source to achieve the desired wireless signal transmit distribution.
6. The information handling system of claim 5 wherein the desired wireless signal transmit distribution comprises substantially a match of the wireless signal transmit distribution across the plural styluses.
7. The information handling system of claim 1 wherein the stylus processing resource couples the receive antenna relative to the power source by applying an alternating current at the receive antenna.
8. The information handling system of claim 1 wherein the stylus processing resource couples the receive antenna relative to the power source by applying a selectable direct current voltage at the receive antenna.
9. The information handling system of claim 5 wherein the stylus processing resource couples the receive antenna relative to the power source by applying one or more of direct current voltage, alternating current voltage and ground.