Capacitive touch keypad
An exemplary an access control device generally includes a keypad assembly, an antenna, and a controller. The keypad assembly includes a capacitive touch keypad matrix, and the antenna is substantially coplanar with the capacitive touch keypad matrix. The controller is connected with each of the keypad assembly and the antenna such that the controller is operable to receive access codes via each of the keypad assembly and the antenna.
1. An access control device, comprising:
a capacitive touch keypad assembly comprising:
a controller;
a plurality of touch-sensitive key locations arranged in a plurality of columns and a plurality of rows;
a plurality of first lines connecting the plurality of rows with the controller; and
a plurality of second lines connecting the plurality of columns with the controller, wherein at least two touch-sensitive key locations in each of the plurality of columns are connected to the controller with a first branch of one the plurality of second lines that is connected between a junction and a first one of the at least two touch-sensitive key locations, a second branch of the one the plurality of second lines that is connected between the junction and a second one of the at least two touch-sensitive key locations, and a third branch connected between the junction and the controller; and
wherein the first branch, the third branch, and a first one of the plurality of first lines connected to the first one of the at least two touch-sensitive key locations form a first loop that is in electrical parallel with a second loop formed by the second branch, the third branch, and a second one of the plurality of first lines connected to the second one of the at least two touch-sensitive key locations.
2. The access control device of claim 1 , wherein the third branch is located between and parallel to adjacent ones of the plurality of rows.
3. The access control device of claim 1 , wherein the junction is a three-way junction.
4. The access control device of claim 1 , wherein the first and second ones of the at least two touch-sensitive key locations key are positioned on opposite sides of the junction.
5. The access control device of claim 1 , further comprising an antenna connected with the controller and configured to transmit an access code to the controller.
6. The access control device of claim 5 , wherein the antenna circumferentially surrounds the plurality of touch-sensitive key locations.
7. The access control device of claim 6 , further comprising a single printed circuit board, and the plurality of touch-sensitive key locations and the antenna are on the single printed circuit board.
8. The access control device of claim 7 , wherein the controller is on the single printed circuit board.
9. The access control device of claim 1 , wherein:
each of the plurality of first lines is a receive line;
each of the plurality of second lines is a transmit line; and
the controller is configured to transmit signals via the transmit lines, to receive the signals via the receive lines, and to determine key touches based upon the received signals.
10. The access control device of claim 9 , wherein the controller is configured to transmit an unlock signal in response to receiving an authorized access code via either of the capacitive touch keypad assembly and the antenna.
11. An access control device, comprising:
a controller;
a capacitive touch keypad matrix, comprising:
a plurality of touch-sensitive key locations arranged in a plurality of columns and a plurality of rows;
a plurality of first lines, each first line connecting the controller with a corresponding and respective column of the plurality of columns; and
a plurality of second lines, each second line connecting the controller with a corresponding and respective row of the plurality of rows; and
wherein each of the plurality of first lines includes a junction and comprises:
a first branch positioned between the junction and a first row of the plurality of rows;
a second branch positioned between the junction and a second row of the plurality of rows; and
a third branch positioned between the junction and the controller; and
wherein the first branch, the third branch, and a first one of the plurality of second lines connected to a first row of the plurality of rows form a first loop that is in electrical parallel with a second loop formed by the second branch, the third branch, and a second one of the plurality of second lines connected to a second row of the plurality of rows.
12. The access control device of claim 11 , further comprising:
a printed circuit board;
an antenna circumferentially surrounding the capacitive touch keypad matrix on the printed circuit board; and
the controller is on the printed circuit board and is configured to receive and authorize an access code from the antenna and/or the capacitive touch keypad matrix to transmit an unlock signal.
13. An access control device, comprising:
a keypad assembly comprising a capacitive touch keypad matrix; and
a controller connected with the capacitive touch keypad matrix;
wherein the capacitive touch keypad matrix comprises a first key location, a second key location, a first line, a second line, and a third line;
wherein the first line comprises a first branch connected between a junction and the first key location, a second branch connected between the junction and the second key location, and a third branch connected between the junction and the controller;
wherein the second line is connected between the first key location and the controller, and wherein the third line is connected between the second key location and the controller; and
wherein the first branch, the third branch, and the second line form a first loop that is in electrical parallel with a second loop formed by the second branch, the third branch, and the third line.
14. The access control device of claim 13 , wherein the keypad assembly further comprises an antenna; and
wherein capacitive touch keypad matrix and the antenna are provided on a single printed circuit board.
15. The access control device of claim 14 , wherein the controller is provided on the single printed circuit board.
16. The access control device of claim 14 , wherein the antenna is configured to transmit an access code from a smart card or a mobile device to the controller.
17. The access control device of claim 16 , further comprising a lock mechanism and wherein the controller is configured to match the access code received from the antenna with an authorized access code and, in response, transmit an unlock signal to the lock mechanism.
18. The access control device of claim 14 , wherein the controller is directly connected to each of the capacitive touch keypad matrix and the antenna.
19. The access control device of claim 13 , wherein the keypad assembly further comprises an antenna coplanar with and circumferentially surrounding the capacitive touch keypad matrix.
20. The access control device of claim 13 , wherein the keypad assembly further comprises an antenna; and
wherein the controller is connected with the antenna such that the controller is operable to receive access codes via each of the capacitive touch keypad matrix and the antenna.