/*
* ReceiverTimingAnalysis.cpp
*
* This program enables the pin change interrupt at pin 3 and waits for NEC (or other Pulse-Distance-Coding) IR Signal.
* It measures the pulse and pause times of the incoming signal and computes some statistics for it.
*
* Observed values:
* Delta of each signal type is around 50 up to 100 and at low signals up to 200. TSOP is better, especially at low IR signal level.
* VS1838 Mark Excess -50 to +50 us
* TSOP31238 Mark Excess 0 to +50
*
*
* Copyright (C) 2019-2020 Armin Joachimsmeyer
* [email protected]
*
* This file is part of IRMP https://github.com/ukw100/IRMP.
* This file is part of Arduino-IRremote https://github.com/Arduino-IRremote/Arduino-IRremote.
*
* IRMP is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/gpl.html>.
*
*/
#include <Arduino.h>
#define IR_INPUT_PIN 3
/*
* Helper macro for getting a macro definition as string
*/
#define STR_HELPER(x) #x
#define STR(x) STR_HELPER(x)
void measureTimingISR(void);
void setup()
{
pinMode(LED_BUILTIN, OUTPUT);
Serial.begin(115200);
#if defined(__AVR_ATmega32U4__) || defined(SERIAL_USB) || defined(SERIAL_PORT_USBVIRTUAL) || defined(ARDUINO_attiny3217)
delay(4000); // To be able to connect Serial monitor after reset or power up and before first print out. Do not wait for an attached Serial Monitor!
#endif
// Just to know which program is running on my Arduino
Serial.println(F("START " __FILE__ " from " __DATE__));
#if defined(EICRA) && defined(EIFR) && defined(EIMSK)
// enable interrupt on pin3 on both edges for ATmega328
EICRA |= _BV(ISC10);
// clear interrupt bit
EIFR |= 1 << INTF1;
// enable interrupt on next change
EIMSK |= 1 << INT1;
#else
attachInterrupt(digitalPinToInterrupt(IR_INPUT_PIN), measureTimingISR, CHANGE);
#endif
Serial.println(F("Ready to analyze NEC IR signal at pin " STR(IR_INPUT_PIN)));
Serial.println();
}
uint8_t ISREdgeCounter = 0;
volatile uint32_t LastMicros;
struct timingStruct
{
uint16_t minimum;
uint8_t indexOfMinimum;
uint16_t maximum;
uint8_t indexOfMaximum;
uint16_t average;
uint16_t SumForAverage;
uint8_t SampleCount;
// uint8_t LastPrintedCount;
};
struct timingStruct Mark;
struct timingStruct ShortSpace;
struct timingStruct LongSpace;
/*
* Compute minimum, maximum and average
*/
void processTmingValue(struct timingStruct *aTimingStruct, uint16_t aValue)
{
if (aTimingStruct->SampleCount == 0)
{
// initialize values
aTimingStruct->minimum = 0xFFFF;
aTimingStruct->maximum = 0;
aTimingStruct->SumForAverage = 0;
}
if (aTimingStruct->minimum > aValue)
{
aTimingStruct->minimum = aValue;
aTimingStruct->indexOfMinimum = aTimingStruct->SampleCount;
}
if (aTimingStruct->maximum < aValue)
{
aTimingStruct->maximum = aValue;
aTimingStruct->indexOfMaximum = aTimingStruct->SampleCount;
}
aTimingStruct->SampleCount++;
aTimingStruct->SumForAverage += aValue;
aTimingStruct->average = (aTimingStruct->SumForAverage + (aTimingStruct->SampleCount / 2)) / aTimingStruct->SampleCount;
}
void printTimingValues(struct timingStruct *aTimingStruct, const char *aCaption)
{
// if (aTimingStruct->LastPrintedCount != aTimingStruct->SampleCount)
// {
// aTimingStruct->LastPrintedCount = aTimingStruct->SampleCount;
Serial.print(aCaption);
Serial.print(F(": SampleCount="));
Serial.print(aTimingStruct->SampleCount);
Serial.print(F(" Minimum="));
Serial.print(aTimingStruct->minimum);
Serial.print(F(" @"));
Serial.print(aTimingStruct->indexOfMinimum);
Serial.print(F(" Maximum="));
Serial.print(aTimingStruct->maximum);
Serial.print(F(" @"));
Serial.print(aTimingStruct->indexOfMaximum);
Serial.print(F(" Delta="));
Serial.print(aTimingStruct->maximum - aTimingStruct->minimum);
Serial.print(F(" Average="));
Serial.print(aTimingStruct->average);
Serial.println();
// }
}
void loop()
{
if (Mark.SampleCount >= 32)
{
/*
* This check enables statistics for longer protocols like Kaseikyo/Panasonics
*/
#if !defined(ARDUINO_ARCH_MBED)
noInterrupts();
#endif
uint32_t tLastMicros = LastMicros;
#if !defined(ARDUINO_ARCH_MBED)
interrupts();
#endif
uint32_t tMicrosDelta = micros() - tLastMicros;
if (tMicrosDelta > 10000)
{
// NEC signal ended just now
Serial.println();
printTimingValues(&Mark, "Mark ");
printTimingValues(&ShortSpace, "ShortSpace");
printTimingValues(&LongSpace, "LongSpace ");
/*
* Print analysis of mark and short spaces
*/
Serial.println(F("Analysis :"));
Serial.print(F(" Average (Mark + ShortSpace)/2="));
int16_t MarkAndShortSpaceAverage = (Mark.average + ShortSpace.average) / 2;
Serial.print(MarkAndShortSpaceAverage);
Serial.print(F("us Delta (to NEC standard 560)="));
Serial.print(MarkAndShortSpaceAverage - 560);
Serial.print(F("us\r\n Mark - Average -> MarkExcess="));
Serial.print((int16_t) Mark.average - MarkAndShortSpaceAverage);
Serial.print(F("us"));
Serial.println();
Serial.println();
Mark.SampleCount = 0; // used as flag for not printing the results more than once
}
}
}
/*
* The interrupt handler.
* Just add to the appropriate timing structure.
*/
#if defined(ESP8266)
ICACHE_RAM_ATTR
#elif defined(ESP32)
IRAM_ATTR
#endif
#if defined(EICRA) && defined(EIFR) && defined(EIMSK)
ISR(INT1_vect)
#else
void measureTimingISR()
#endif
{
uint32_t tMicros = micros();
uint32_t tMicrosDelta = tMicros - LastMicros;
LastMicros = tMicros;
/*
* read level and give feedback
*/
uint8_t tInputLevel = digitalRead(IR_INPUT_PIN);
digitalWrite(LED_BUILTIN, !tInputLevel);
if (tMicrosDelta > 10000)
{
// gap > 10 ms detected, reset counter to first detected edge and initialize timing structures
ISREdgeCounter = 1;
LongSpace.SampleCount = 0;
ShortSpace.SampleCount = 0;
Mark.SampleCount = 0;
}
else
{
ISREdgeCounter++;
}
/*
* Skip header mark and space and first bit mark and space
*/
if (ISREdgeCounter > 4)
{
if (tInputLevel != LOW)
{
// Mark ended
processTmingValue(&Mark, tMicrosDelta);
// Serial.print('M');
}
else
{
// Space ended
if (tMicrosDelta > 1000)
{
// long space - logical 1
processTmingValue(&LongSpace, tMicrosDelta);
Serial.print('1');
}
else
{
// short space - logical 0
processTmingValue(&ShortSpace, tMicrosDelta);
Serial.print('0');
}
}
}
}