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/*
* Copyright 2015 Google Inc.
*
* 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.
*/
/*
* Firmware of piropiro (party horn) Bluetooth keyboard.
*/
#define V_REF 5.0
#define PIN_LED 13
#define N_AD_SAMPLES 10
#define INTERVAL_MSEC 20
#define COMMIT_TIME (600 / INTERVAL_MSEC)
#define ROWS 5
#define COLS 10
const char* characters[ROWS * COLS] = {
"a", "i", "u", "e", "o",
"ka", "ki", "ku", "ke", "ko",
"sa", "si", "su", "se", "so",
"ta", "ti", "tu", "te", "to",
"na", "ni", "nu", "ne", "no",
"ha", "hi", "hu", "he", "ho",
"ma", "mi", "mu", "me", "mo",
"ya", "ya", "yu", "yu", "yo",
"ra", "ri", "ru", "re", "ro",
"wa", "wo", "nn", ",", "."
};
int column = 0;
int vowel = 0;
int release_duration = 0;
void setup() {
Serial.begin(115200);
pinMode(PIN_LED, OUTPUT);
column = 0;
vowel = 0;
}
float getVoltage(int ch) {
return analogRead(ch) * V_REF / 1023;
}
float getAverageVoltage(int ch) {
float sum = 0.0;
for (int i = 0; i < N_AD_SAMPLES; i++) {
sum += getVoltage(ch);
}
return sum / N_AD_SAMPLES;
}
float voltageToLength(float voltage) {
return 648 - voltage * 268;
}
void loop() {
float length = voltageToLength(getAverageVoltage(0));
if (length > 350) {
digitalWrite(PIN_LED, LOW);
} else {
digitalWrite(PIN_LED, HIGH);
if (length < 50) {
if (vowel > 0) {
vowel = 0;
column ++;
if (column >= COLS) {
column = 0;
}
release_duration = 0;
} else if (release_duration > COMMIT_TIME) {
vowel = 0;
column = 0;
} else if (column > 0) {
release_duration ++;
}
} else {
int target_vowel = (length - 80) / 40 + 1;
if (target_vowel > 5) target_vowel = 5;
if (vowel < target_vowel) {
if (column > 0 || vowel > 0) {
Serial.print("\b");
}
vowel ++;
int current_character = vowel - 1 + column * 5;
Serial.print(characters[current_character]);
}
}
}
delay(INTERVAL_MSEC);
}