Shinichiro Nakamura / TouchSense

A capacitive touch sensor using a analog input port.

Dependents:   TouchSenseTestProgram

TouchSense.h@0:5a0704efe081, 2013-08-14 (annotated)

Committer:
shintamainjp
Date:
Wed Aug 14 09:08:59 2013 +0000
Revision:
0:5a0704efe081
Child:
1:08658b9787d8
This is the initial version.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
shintamainjp 0:5a0704efe081 1 /* mbed Microcontroller Library
shintamainjp 0:5a0704efe081 2 * Copyright (c) 2013 Shinichiro Nakamura
shintamainjp 0:5a0704efe081 3 *
shintamainjp 0:5a0704efe081 4 * Licensed under the Apache License, Version 2.0 (the "License");
shintamainjp 0:5a0704efe081 5 * you may not use this file except in compliance with the License.
shintamainjp 0:5a0704efe081 6 * You may obtain a copy of the License at
shintamainjp 0:5a0704efe081 7 *
shintamainjp 0:5a0704efe081 8 * http://www.apache.org/licenses/LICENSE-2.0
shintamainjp 0:5a0704efe081 9 *
shintamainjp 0:5a0704efe081 10 * Unless required by applicable law or agreed to in writing, software
shintamainjp 0:5a0704efe081 11 * distributed under the License is distributed on an "AS IS" BASIS,
shintamainjp 0:5a0704efe081 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
shintamainjp 0:5a0704efe081 13 * See the License for the specific language governing permissions and
shintamainjp 0:5a0704efe081 14 * limitations under the License.
shintamainjp 0:5a0704efe081 15 */
shintamainjp 0:5a0704efe081 16
shintamainjp 0:5a0704efe081 17 #ifndef TOUCHSENSE_H
shintamainjp 0:5a0704efe081 18 #define TOUCHSENSE_H
shintamainjp 0:5a0704efe081 19
shintamainjp 0:5a0704efe081 20 #include "platform.h"
shintamainjp 0:5a0704efe081 21 #include "gpio_api.h"
shintamainjp 0:5a0704efe081 22 #include "analogin_api.h"
shintamainjp 0:5a0704efe081 23
shintamainjp 0:5a0704efe081 24 namespace mbed {
shintamainjp 0:5a0704efe081 25
shintamainjp 0:5a0704efe081 26 /**
shintamainjp 0:5a0704efe081 27 * A capacitive touch sensor using analog input port.
shintamainjp 0:5a0704efe081 28 *
shintamainjp 0:5a0704efe081 29 * Example:
shintamainjp 0:5a0704efe081 30 * @code
shintamainjp 0:5a0704efe081 31 * #include "mbed.h"
shintamainjp 0:5a0704efe081 32 *
shintamainjp 0:5a0704efe081 33 * TouchSense tp(p18);
shintamainjp 0:5a0704efe081 34 *
shintamainjp 0:5a0704efe081 35 * int main() {
shintamainjp 0:5a0704efe081 36 * tp.calibration();
shintamainjp 0:5a0704efe081 37 * while(1) {
shintamainjp 0:5a0704efe081 38 * if (tp.sense()) {
shintamainjp 0:5a0704efe081 39 * printf("ON\r\n");
shintamainjp 0:5a0704efe081 40 * } else {
shintamainjp 0:5a0704efe081 41 * printf("OFF\r\n");
shintamainjp 0:5a0704efe081 42 * }
shintamainjp 0:5a0704efe081 43 * wait(0.1);
shintamainjp 0:5a0704efe081 44 * }
shintamainjp 0:5a0704efe081 45 * }
shintamainjp 0:5a0704efe081 46 * @endcode
shintamainjp 0:5a0704efe081 47 */
shintamainjp 0:5a0704efe081 48 class TouchSense {
shintamainjp 0:5a0704efe081 49
shintamainjp 0:5a0704efe081 50 public:
shintamainjp 0:5a0704efe081 51 /**
shintamainjp 0:5a0704efe081 52 * Create a TouchSense connected to the specified pin
shintamainjp 0:5a0704efe081 53 *
shintamainjp 0:5a0704efe081 54 * @param pin TouchSense pin to connect to
shintamainjp 0:5a0704efe081 55 */
shintamainjp 0:5a0704efe081 56 TouchSense(PinName pin) : mypin(pin), calval(0) {
shintamainjp 0:5a0704efe081 57 }
shintamainjp 0:5a0704efe081 58
shintamainjp 0:5a0704efe081 59 void calibration() {
shintamainjp 0:5a0704efe081 60 uint16_t f1, f2, f3, f4;
shintamainjp 0:5a0704efe081 61 f1 = execute();
shintamainjp 0:5a0704efe081 62 f2 = execute();
shintamainjp 0:5a0704efe081 63 f3 = execute();
shintamainjp 0:5a0704efe081 64 f4 = execute();
shintamainjp 0:5a0704efe081 65 calval = (f1 + f2 + f3 + f4) / 4.0;
shintamainjp 0:5a0704efe081 66 }
shintamainjp 0:5a0704efe081 67
shintamainjp 0:5a0704efe081 68 bool sense() {
shintamainjp 0:5a0704efe081 69 uint16_t f = execute();
shintamainjp 0:5a0704efe081 70 return (calval * 3.00) < f;
shintamainjp 0:5a0704efe081 71 }
shintamainjp 0:5a0704efe081 72
shintamainjp 0:5a0704efe081 73 private:
shintamainjp 0:5a0704efe081 74
shintamainjp 0:5a0704efe081 75 uint16_t execute() {
shintamainjp 0:5a0704efe081 76 gpio_init(&gpio, mypin, PIN_OUTPUT);
shintamainjp 0:5a0704efe081 77 gpio_write(&gpio, 1);
shintamainjp 0:5a0704efe081 78 __nop();
shintamainjp 0:5a0704efe081 79 __nop();
shintamainjp 0:5a0704efe081 80 __nop();
shintamainjp 0:5a0704efe081 81 __nop();
shintamainjp 0:5a0704efe081 82 analogin_init(&adc, mypin);
shintamainjp 0:5a0704efe081 83 return analogin_read_u16(&adc);
shintamainjp 0:5a0704efe081 84 }
shintamainjp 0:5a0704efe081 85
shintamainjp 0:5a0704efe081 86 protected:
shintamainjp 0:5a0704efe081 87 PinName mypin;
shintamainjp 0:5a0704efe081 88 uint16_t calval;
shintamainjp 0:5a0704efe081 89 gpio_t gpio;
shintamainjp 0:5a0704efe081 90 analogin_t adc;
shintamainjp 0:5a0704efe081 91 };
shintamainjp 0:5a0704efe081 92
shintamainjp 0:5a0704efe081 93 } // namespace mbed
shintamainjp 0:5a0704efe081 94
shintamainjp 0:5a0704efe081 95 #endif