# US 2014/0191795 A1 · Method for controlling operations of input device having resistor matrix > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0191795 A1 - Document ID: US20140191795A1 - Status: Published application - Kind: A1 - Application number: 14/147,568 - Filed: 2014-01-05 - Published: 2014-07-10 - Earliest claimed: 2013-01-08 - Assignees: Universal Cement Corporation - Applicants: Universal Cement Corporation - Inventors: Chih-Hung Huang; Chih-Sheng Hou - Web page: https://patentgrep.com/patent/US20140191795A1 ## CPC - G06F 3/045: using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact - H03K 17/9625: {using a force resistance transducer} - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) ## Abstract A method for controlling an input device is provided. The input device has a resistor matrix having M first traces, N second traces and M×N resistors. Each second trace is coupled to a reference resistor and M−1 variable resistors. M and N are integers greater than 1. A first voltage level of each second trace is measured when a first voltage is applied to a first end of the reference resistor and a second voltage is applied to first ends of the M−1 variable resistors via the M first traces. Variations of the first voltage level of each second trace are measured, such that it could be determined whether any touch point of the input device exists according to the variations of the first voltage level of each second trace. ## Claims ### Claim 1 A method for controlling operations of an input device, the input device comprising a resistor matrix having M first traces, N second traces and M×N resistors, first ends of resistors of a same column being connected to one of the M first traces, second ends of resistors of a same row being connected to one of the N second traces, and each second trace being coupled to a reference resistor and M−1 variable resistors, M and N being integers greater than 1, the method comprising: measuring a first voltage level of the each second trace when a first voltage is applied to a first end of the reference resistor and a second voltage is applied to first ends of the M−1 variable resistors via the M first traces; measuring variations of the first voltage level of the each second trace; and determining at least one touch point of the input device according to the variations of the first voltage level of the each second trace. ### Claim 2 (depends on 1) The method of claim 1, wherein when the variations of the first voltage level satisfy predetermined criteria, the at least one touch point is determined to being triggered. ### Claim 3 (depends on 1) The method of claim 1 further comprising: determining whether the at least one touch point of the input device is being triggered according to the variations of the first voltage level of the each second trace; determining a first coordinate of the at least one touch point according to the variations of the first voltage level of the each second trace; when the at least touch point is determined to being triggered, obtaining M−1 second measured voltage levels of a second trace at the first coordinate by applying the first voltage to first ends of M−1 variable resistors at the first coordinate via M−1 first traces within M−1 periods in a predetermined sequence, wherein when the first voltage is applied a first end of one of the M−1 variable resistors, the second voltage is applied to first ends of the reference resistor and remaining M−2 variable resistors; and determining a second coordinate of the at least one touch point according to the first voltage level and the M−1 second measured voltage levels. ### Claim 4 (depends on 3) The method of claim 3 further comprising: after obtaining the M−1 second measured voltage levels, stop applying the first voltage to the first ends of the M−1 variable resistors at the first coordinate, and keeping measuring the variations of the first voltage level of the each second trace by applying the first voltage to the first end of the reference resistor and applying the second voltage to the first ends of the M−1 variable resistors of each row of the resistor matrix so as to determine whether another touch point of the input device is being triggered. ### Claim 5 (depends on 1) The method of claim 1 further comprising: obtaining M−1 second measured voltage levels of each second trace by applying the first voltage to the first ends of M−1 variable resistors in a predetermined sequence, wherein when the first voltage is applied a first end of one of the M−1 variable resistors, the second voltage is applied to first ends of the reference resistor and remaining M−2 variable resistors; and determining a first coordinate and a second coordinate of the at least one touch point according to the first voltage level and the M−1 second measured voltage levels. ### Claim 6 (depends on 5) The method of claim 5 further comprising: determining strength of a force applied to the at least one touch point according to the first voltage level and a second measured voltage level corresponded to the second coordinate. ### Claim 7 (depends on 6) The method of claim 6, wherein the strength of the force is obtained according to a function of ( ADC   2 ADC   1 × R REF ) , where ADC2 is the second measured voltage level corresponded to the second coordinate, ADC1 is the first voltage level, and RREF is resistance of the reference resistor. ### Claim 8 (depends on 6) The method of claim 6, wherein the strength of the force is determined by using an interpolation algorithm. ### Claim 9 (depends on 6) The method of claim 6, wherein the at least touch point is determined to being triggered if the strength of the force is greater than a predetermined threshold. ### Claim 10 (depends on 6) The method of claim 6, wherein determining the strength of the force applied to the at least one touch point according to the first voltage level and the second measured voltage level corresponded to the second coordinate comprises: selecting a lookup table from a plurality of lookup tables according to the first coordinate and the second coordinate; and selecting a corresponding value from the selected lookup table as the strength of the force according to the first voltage level and the second measured voltage level corresponded to the second coordinate. ### Claim 11 (depends on 6) The method of claim 6, wherein determining the strength of the force applied to the at least one touch point according to the first voltage level and the second measured voltage level corresponded to the second coordinate comprises: selecting a corresponding value from a lookup table as the strength of the force according to the first voltage level and the second measured voltage level corresponded to the second coordinate. ### Claim 12 (depends on 6) The method of claim 6 further comprising: outputting a control signal according to the strength of the force; wherein if the strength of the force is greater than or equal to a first predetermined value, the control signal is a first control signal; wherein if the strength of the force is less than the first predetermined value and not less than a second predetermined value, the control signal is a second control signal; and wherein the second predetermined value is less than the first predetermined value, and the first control signal is different from the second control signal. ### Claim 13 (depends on 6) The method of claim 6 further comprising: outputting information of the strength of the force. ### Claim 14 (depends on 5) The method of claim 5 further comprising: determining resistances of the M−1 variable resistors at the first coordinate according to the first voltage level and the M−1 second measured voltage levels. ### Claim 15 (depends on 14) The method of claim 14, wherein the resistance of a variable resistor of the M−1 variable resistors is equal to ADC   1 × R REF ADC   2 , where ADC1 is the first voltage level, ADC2 is the second measured voltage level corresponded to the variable resistor, and RREF is resistance of the reference resistor. ### Claim 16 (depends on 14) The method of claim 14, wherein the resistances of the M−1 variable resistors at the first coordinate are selected from a lookup table according to the first voltage level and the M−1 second measured voltage levels. ### Claim 17 (depends on 14) The method of claim 14 further comprising: determining strength of a force applied to the at least one touch point according to resistance of a variable resistor at the at least one touch point. ### Claim 18 (depends on 17) The method of claim 17, wherein the strength of the force is obtained according to a function of ( ADC   2 ADC   1 × R REF ) , where ADC2 is the second measured voltage level corresponded to the second coordinate, ADC1 is the first voltage level, and RREF is resistance of the reference resistor. ### Claim 19 (depends on 17) The method of claim 17, wherein the strength of the force is determined by using an interpolation algorithm. ### Claim 20 (depends on 17) The method of claim 17, wherein the at least touch point is determined to being triggered if the strength of the force is greater than a predetermined threshold. ### Claim 21 (depends on 17) The method of claim 17, wherein determining the strength of the force applied to the at least one touch point according to the first voltage level and the second measured voltage level corresponded to the second coordinate comprises: selecting a lookup table from a plurality of lookup tables according to the first coordinate and the second coordinate; and selecting a corresponding value from the selected lookup table as the strength of the force according to resistance of a variable resistors at the at least one touch point. ### Claim 22 (depends on 17) The method of claim 17, wherein determining the strength of the force applied to the at least one touch point according to the first voltage level and the second measured voltage level corresponded to the second coordinate comprises: selecting a corresponding value from a lookup table as the strength of the force according to the resistance of a variable resistors at the at least one touch point. ### Claim 23 (depends on 17) The method of claim 17 further comprising: outputting a control signal according to the strength of the force; wherein if the strength of the force is greater than or equal to a first predetermined value, the control signal is a first control signal; wherein if the strength of the force is less than the first predetermined value and not less than a second predetermined value, the control signal is a second control signal; and wherein the second predetermined value is less than the first predetermined value, and the first control signal is different from the second control signal. ### Claim 24 (depends on 16) The method of claim 16 further comprising: outputting information of the strength of the force. ### Claim 25 (depends on 1) The method of claim 1, wherein steps of the method are repeated at regular intervals. ### Claim 26 (depends on 1) The method of claim 1, wherein the first voltage is constantly applied to the first end of the reference resistor and the second voltage is constantly applied to first ends of the M−1 variable resistors until the at least one touch point is determined to being triggered. ### Claim 27 (depends on 1) The method of claim 1, wherein measuring the variations of the first voltage level of the each second trace comprises: measuring the variations of the first voltage level of the each second trace by a general-purpose input/output (GPIO) circuit. ### Claim 28 (depends on 1) The method of claim 1, wherein a ratio of resistance of the reference resistor to activation force resistance of each of M−1 variable resistors falls in a range of 0.2 to 5.