A capacitive touch sensor using a analog input port.
Dependents: TouchSenseTestProgram
Diff: TouchSense.h
- Revision:
- 0:5a0704efe081
- Child:
- 1:08658b9787d8
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/TouchSense.h Wed Aug 14 09:08:59 2013 +0000 @@ -0,0 +1,95 @@ +/* mbed Microcontroller Library + * Copyright (c) 2013 Shinichiro Nakamura + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#ifndef TOUCHSENSE_H +#define TOUCHSENSE_H + +#include "platform.h" +#include "gpio_api.h" +#include "analogin_api.h" + +namespace mbed { + +/** + * A capacitive touch sensor using analog input port. + * + * Example: + * @code + * #include "mbed.h" + * + * TouchSense tp(p18); + * + * int main() { + * tp.calibration(); + * while(1) { + * if (tp.sense()) { + * printf("ON\r\n"); + * } else { + * printf("OFF\r\n"); + * } + * wait(0.1); + * } + * } + * @endcode + */ +class TouchSense { + +public: + /** + * Create a TouchSense connected to the specified pin + * + * @param pin TouchSense pin to connect to + */ + TouchSense(PinName pin) : mypin(pin), calval(0) { + } + + void calibration() { + uint16_t f1, f2, f3, f4; + f1 = execute(); + f2 = execute(); + f3 = execute(); + f4 = execute(); + calval = (f1 + f2 + f3 + f4) / 4.0; + } + + bool sense() { + uint16_t f = execute(); + return (calval * 3.00) < f; + } + +private: + + uint16_t execute() { + gpio_init(&gpio, mypin, PIN_OUTPUT); + gpio_write(&gpio, 1); + __nop(); + __nop(); + __nop(); + __nop(); + analogin_init(&adc, mypin); + return analogin_read_u16(&adc); + } + +protected: + PinName mypin; + uint16_t calval; + gpio_t gpio; + analogin_t adc; +}; + +} // namespace mbed + +#endif