adding nRF8001 to an existing Arduino UNO project

[TreasureHunter]

Dear forum members!

I'm looking for a skilled Arduino programmer, because I stuck with my project..

The source code is here:
https://github.com/dc42/arduino/blob/master/MetalDetector/MetalDetector.ino

I tried to connect my Arduino UNO to a phone app through nRF8001 bluetooth module following this tutorial:
https://learn.adafruit.com/getting-started-with-the-nrf8001-bluefruit-le-breakout/nrf-uart-in-detail

The example tutorial app works just fine, I could connect to my phone without problem with it, but with this github code above I couldn't.
In the end of the Arduino code it sends a lot of things on the serial port. I only need the "Ferrous" or "Non Ferrous" part to be sent through bluetooth nothing else.
Can someone help me with merging the bluetooth codes with the metal detector's code? I would highly appreciate any help!

Regards,
TH

[Teleno]

Post your code.

[TreasureHunter]

Arduino Metal detector

// Induction balance metal detector
	// We run the CPU at 16MHz and the ADC clock at 1MHz. ADC resolution is reduced to 8 bits at this speed.
	// Timer 1 is used to divide the system clock by about 256 to produce a 62.5kHz square wave.
	// This is used to drive timer 0 and also to trigger ADC conversions.
	// Timer 0 is used to divide the output of timer 1 by 8, giving a 7.8125kHz signal for driving the transmit coil.
	// This gives us 16 ADC clock cycles for each ADC conversion (it actually takes 13.5 cycles), and we take 8 samples per cycle of the coil drive voltage.
	// The ADC implements four phase-sensitive detectors at 45 degree intervals. Using 4 instead of just 2 allows us to cancel the third harmonic of the
	// coil frequency.
	// Timer 2 will be used to generate a tone for the earpiece or headset.
	// Other division ratios for timer 1 are possible, from about 235 upwards.
	// Wiring:
	// Connect digital pin 4 (alias T0) to digital pin 9
	// Connect digital pin 5 through resistor to primary coil and tuning capacitor
	// Connect output from receive amplifier to analog pin 0. Output of receive amplifier should be biased to about half of the analog reference.
	// When using USB power, change analog reference to the 3.3V pin, because there is too much noise on the +5V rail to get good sensitivity.
	#define TIMER1_TOP (249) // can adjust this to fine-tune the frequency to get the coil tuned (see above)
	#define USE_3V3_AREF (1) // set to 1 of running on an Arduino with USB power, 0 for an embedded atmega28p with no 3.3V supply available
	// Digital pin definitions
	// Digital pin 0 not used, however if we are using the serial port for debugging then it's serial input
	const int debugTxPin = 1; // transmit pin reserved for debugging
	const int encoderButtonPin = 2; // encoder button, also IN0 for waking up from sleep mode
	const int earpiecePin = 3; // earpiece, aka OCR2B for tone generation
	const int T0InputPin = 4;
	const int coilDrivePin = 5;
	const int LcdRsPin = 6;
	const int LcdEnPin = 7;
	const int LcdPowerPin = 8; // LCD power and backlight enable
	const int T0OutputPin = 9;
	const int lcdD0Pin = 10;
	const int lcdD1Pin = 11; // pins 11-13 also used for ICSP
	const int LcdD2Pin = 12;
	const int LcdD3Pin = 13;
	// Analog pin definitions
	const int receiverInputPin = 0;
	const int encoderAPin = A1;
	const int encoderBpin = A2;
	// Analog pins 3-5 not used
	// Variables used only by the ISR
	int16_t bins[4]; // bins used to accumulate ADC readings, one for each of the 4 phases
	uint16_t numSamples = 0;
	const uint16_t numSamplesToAverage = 1024;
	// Variables used by the ISR and outside it
	volatile int16_t averages[4]; // when we've accumulated enough readings in the bins, the ISR copies them to here and starts again
	volatile uint32_t ticks = 0; // system tick counter for timekeeping
	volatile bool sampleReady = false; // indicates that the averages array has been updated
	// Variables used only outside the ISR
	int16_t calib[4]; // values (set during calibration) that we subtract from the averages
	volatile uint8_t lastctr;
	volatile uint16_t misses = 0; // this counts how many times the ISR has been executed too late. Should remain at zero if everything is working properly.
	const double halfRoot2 = sqrt(0.5);
	const double quarterPi = 3.1415927/4.0;
	const double radiansToDegrees = 180.0/3.1415927;
	// The ADC sample and hold occurs 2 ADC clocks (= 32 system clocks) after the timer 1 overflow flag is set.
	// This introduces a slight phase error, which we adjust for in the calculations.
	const float phaseAdjust = (45.0 * 32.0)/(float)(TIMER1_TOP + 1);
	float threshold = 10.0; // lower = greater sensitivity. 10 is just about usable with a well-balanced coil.
	// The user will be able to adjust this via a pot or rotary encoder.
	void setup()
	{
	pinMode(encoderButtonPin, INPUT_PULLUP);
	digitalWrite(T0OutputPin, LOW);
	pinMode(T0OutputPin, OUTPUT); // pulse pin from timer 1 used to feed timer 0
	digitalWrite(coilDrivePin, LOW);
	pinMode(coilDrivePin, OUTPUT); // timer 0 output, square wave to drive transmit coil
	cli();
	// Stop timer 0 which was set up by the Arduino core
	TCCR0B = 0; // stop the timer
	TIMSK0 = 0; // disable interrupt
	TIFR0 = 0x07; // clear any pending interrupt
	// Set up ADC to trigger and read channel 0 on timer 1 overflow
	#if USE_3V3_AREF
	ADMUX = (1 << ADLAR); // use AREF pin (connected to 3.3V) as voltage reference, read pin A0, left-adjust result
	#else
	ADMUX = (1 << REFS0) | (1 << ADLAR); // use Avcc as voltage reference, read pin A0, left-adjust result
	#endif
	ADCSRB = (1 << ADTS2) | (1 << ADTS1); // auto-trigger ADC on timer/counter 1 overflow
	ADCSRA = (1 << ADEN) | (1 << ADSC) | (1 << ADATE) | (1 << ADPS2); // enable adc, enable auto-trigger, prescaler = 16 (1MHz ADC clock)
	DIDR0 = 1;
	// Set up timer 1.
	// Prescaler = 1, phase correct PWM mode, TOP = ICR1A
	TCCR1A = (1 << COM1A1) | (1 << WGM11);
	TCCR1B = (1 << WGM12) | (1 << WGM13) | (1 << CS10); // CTC mode, prescaler = 1
	TCCR1C = 0;
	OCR1AH = (TIMER1_TOP/2 >> 8);
	OCR1AL = (TIMER1_TOP/2 & 0xFF);
	ICR1H = (TIMER1_TOP >> 8);
	ICR1L = (TIMER1_TOP & 0xFF);
	TCNT1H = 0;
	TCNT1L = 0;
	TIFR1 = 0x07; // clear any pending interrupt
	TIMSK1 = (1 << TOIE1);
	// Set up timer 0
	// Clock source = T0, fast PWM mode, TOP (OCR0A) = 7, PWM output on OC0B
	TCCR0A = (1 << COM0B1) | (1 << WGM01) | (1 << WGM00);
	TCCR0B = (1 << CS00) | (1 << CS01) | (1 << CS02) | (1 << WGM02);
	OCR0A = 7;
	OCR0B = 3;
	TCNT0 = 0;
	sei();
	while (!sampleReady) {} // discard the first sample
	misses = 0;
	sampleReady = false;
	Serial.begin(19200);
	}
	// Timer 0 overflow interrupt. This serves 2 purposes:
	// 1. It clears the timer 0 overflow flag. If we don't do this, the ADC will not see any more Timer 0 overflows and we will not get any more conversions.
	// 2. It increments the tick counter, allowing is to do timekeeping. We get 62500 ticks/second.
	// We now read the ADC in the timer interrupt routine instead of having a separate comversion complete interrupt.
	ISR(TIMER1_OVF_vect)
	{
	++ticks;
	uint8_t ctr = TCNT0;
	int16_t val = (int16_t)(uint16_t)ADCH; // only need to read most significant 8 bits
	if (ctr != ((lastctr + 1) & 7))
	{
	++misses;
	}
	lastctr = ctr;
	int16_t *p = &bins[ctr & 3];
	if (ctr < 4)
	{
	*p += (val);
	if (*p > 15000) *p = 15000;
	}
	else
	{
	*p -= val;
	if (*p < -15000) *p = -15000;
	}
	if (ctr == 7)
	{
	++numSamples;
	if (numSamples == numSamplesToAverage)
	{
	numSamples = 0;
	if (!sampleReady) // if previous sample has been consumed
	{
	memcpy((void*)averages, bins, sizeof(averages));
	sampleReady = true;
	}
	memset(bins, 0, sizeof(bins));
	}
	}
	}
	void loop()
	{
	while (!sampleReady) {}
	uint32_t oldTicks = ticks;
	if (digitalRead(encoderButtonPin) == LOW)
	{
	// Calibrate button pressed. We save the current phase detector outputs and subtract them from future results.
	// This lets us use the detector if the coil is slightly off-balance.
	// It would be better to everage several samples instead of taking just one.
	for (int i = 0; i < 4; ++i)
	{
	calib[i] = averages[i];
	}
	sampleReady = false;
	Serial.print("Calibrated: ");
	for (int i = 0; i < 4; ++i)
	{
	Serial.write(' ');
	Serial.print(calib[i]);
	}
	Serial.println();
	}
	else
	{
	for (int i = 0; i < 4; ++i)
	{
	averages[i] -= calib[i];
	}
	const double f = 200.0;
	// Massage the results to eliminate sensitivity to the 3rd harmonic, and divide by 200
	double bin0 = (averages[0] + halfRoot2 * (averages[1] - averages[3]))/f;
	double bin1 = (averages[1] + halfRoot2 * (averages[0] + averages[2]))/f;
	double bin2 = (averages[2] + halfRoot2 * (averages[1] + averages[3]))/f;
	double bin3 = (averages[3] + halfRoot2 * (averages[2] - averages[0]))/f;
	sampleReady = false; // we've finished reading the averages, so the ISR is free to overwrite them again
	double amp1 = sqrt((bin0 * bin0) + (bin2 * bin2));
	double amp2 = sqrt((bin1 * bin1) + (bin3 * bin3));
	double ampAverage = (amp1 + amp2)/2.0;
	// The ADC sample/hold takes place 2 clocks after the timer overflow
	double phase1 = atan2(bin0, bin2) * radiansToDegrees + 45.0;
	double phase2 = atan2(bin1, bin3) * radiansToDegrees;
	if (phase1 > phase2)
	{
	double temp = phase1;
	phase1 = phase2;
	phase2 = temp;
	}
	double phaseAverage = ((phase1 + phase2)/2.0) - phaseAdjust;
	if (phase2 - phase1 > 180.0)
	{
	if (phaseAverage < 0.0)
	{
	phaseAverage += 180.0;
	}
	else
	{
	phaseAverage -= 180.0;
	}
	}
	// For diagnostic purposes, print the individual bin counts and the 2 indepedently-calculated gains and phases
	Serial.print(misses);
	Serial.write(' ');
	if (bin0 >= 0.0) Serial.write(' ');
	Serial.print(bin0, 2);
	Serial.write(' ');
	if (bin1 >= 0.0) Serial.write(' ');
	Serial.print(bin1, 2);
	Serial.write(' ');
	if (bin2 >= 0.0) Serial.write(' ');
	Serial.print(bin2, 2);
	Serial.write(' ');
	if (bin3 >= 0.0) Serial.write(' ');
	Serial.print(bin3, 2);
	Serial.print(" ");
	Serial.print(amp1, 2);
	Serial.write(' ');
	Serial.print(amp2, 2);
	Serial.write(' ');
	if (phase1 >= 0.0) Serial.write(' ');
	Serial.print(phase1, 2);
	Serial.write(' ');
	if (phase2 >= 0.0) Serial.write(' ');
	Serial.print(phase2, 2);
	Serial.print(" ");
	// Print the final amplitude and phase, which we use to decide what (if anything) we have found)
	if (ampAverage >= 0.0) Serial.write(' ');
	Serial.print(ampAverage, 1);
	Serial.write(' ');
	if (phaseAverage >= 0.0) Serial.write(' ');
	Serial.print((int)phaseAverage);
	// Decide what we have found and tell the user
	if (ampAverage >= threshold)
	{
	// When held in line with the centre of the coil:
	// - non-ferrous metals give a negative phase shift, e.g. -90deg for thick copper or aluminium, a copper olive, -30deg for thin alumimium.
	// Ferrous metals give zero phase shift or a small positive phase shift.
	// So we'll say that anything with a phase shift below -20deg is non-ferrous.
	if (phaseAverage < -20.0)
	{
	Serial.print(" Non-ferrous");
	}
	else
	{
	Serial.print(" Ferrous");
	}
	float temp = ampAverage;
	while (temp > threshold)
	{
	Serial.write('!');
	temp -= (threshold/2);
	}
	}
	Serial.println();
	}
	while (ticks - oldTicks < 16000)
	{
	}
	}

Adafruit bluetooth module:

// This version uses the internal data queing so you can treat it like Serial (kinda)!


#include <SPI.h>
#include "Adafruit_BLE_UART.h"


// Connect CLK/MISO/MOSI to hardware SPI
// e.g. On UNO & compatible: CLK = 13, MISO = 12, MOSI = 11
#define ADAFRUITBLE_REQ 10
#define ADAFRUITBLE_RDY 2 // This should be an interrupt pin, on Uno thats #2 or #3
#define ADAFRUITBLE_RST 9


Adafruit_BLE_UART BTLEserial = Adafruit_BLE_UART(ADAFRUITBLE_REQ, ADAFRUITBLE_RDY, ADAFRUITBLE_RST);
/************************************************** ************************/
/*!
Configure the Arduino and start advertising with the radio
*/
/************************************************** ************************/
void setup(void)
{
Serial.begin(9600);
Serial.println(F("Adafruit Bluefruit Low Energy nRF8001 Print echo demo"));


BTLEserial.begin();
}


/************************************************** ************************/
/*!
Constantly checks for new events on the nRF8001
*/
/************************************************** ************************/
aci_evt_opcode_t laststatus = ACI_EVT_DISCONNECTED;


void loop()
{
// Tell the nRF8001 to do whatever it should be working on.
BTLEserial.pollACI();

// Ask what is our current status
aci_evt_opcode_t status = BTLEserial.getState();
// If the status changed....
if (status != laststatus) {
// print it out!
if (status == ACI_EVT_DEVICE_STARTED) {
Serial.println(F("* Advertising started"));
}
if (status == ACI_EVT_CONNECTED) {
Serial.println(F("* Connected!"));
}
if (status == ACI_EVT_DISCONNECTED) {
Serial.println(F("* Disconnected or advertising timed out"));
}
// OK set the last status change to this one
laststatus = status;
}

if (status == ACI_EVT_CONNECTED) {
// Lets see if there's any data for us!
if (BTLEserial.available()) {
Serial.print("* "); Serial.print(BTLEserial.available()); Serial.println(F(" bytes available from BTLE"));
}
// OK while we still have something to read, get a character and print it out
while (BTLEserial.available()) {
char c = BTLEserial.read();
Serial.print(c);
}

// Next up, see if we have any data to get from the Serial console


if (Serial.available()) {
// Read a line from Serial
Serial.setTimeout(100); // 100 millisecond timeout
String s = Serial.readString();


// We need to convert the line to bytes, no more than 20 at this time
uint8_t sendbuffer[20];
s.getBytes(sendbuffer, 20);
char sendbuffersize = min(20, s.length());

Serial.print(F("\n* Sending -> \"")); Serial.print((char *)sendbuffer); Serial.println("\"");

// write the data
BTLEserial.write(sendbuffer, sendbuffersize);
}
}
}

These two should be merged together, but I just gave up...
You can ignore or delete the LCD stuff, because there is no LCD used in this project.

[Teleno]

Post the code you merged.

[TreasureHunter]

http://pastebin.com/eQAR6h6V

This should work like this:
- it writes out: Advertising
- Than I connect to it with my phone, than it should write: connected
- after connection it should start the metal detecting stuff
- finally when I find something it should write back to my phone what I found

but this is not working, it doesn't even goes in to the loop(), but stays in that function before loop..

[Teleno]

I you don't post the code of your failed attempt we'll think you have made no attempt at all. It seems you're just trying to have us work for you for free.

[TreasureHunter]

that is not the case, I'm not trying to get free work done
Whoever helps me to make this work gets 25 euro from me, this is my offer!
I have some progress:
- the metal detector uses Timer 0 and Timer 1, and the Bluetooth module also uses a clock in SCK pin
- I think that there is a conflict because the module also tries to use Timer 0 or Timer 1 here
- so somehow we should tell Arduino to use Timer2 on his digital pin13, does someone know how to do it?

[ivconic]

that is not the case, I'm not trying to get free work done
Whoever helps me to make this work gets 25 euro from me, this is my offer!
I have some progress:
- the metal detector uses Timer 0 and Timer 1, and the Bluetooth module also uses a clock in SCK pin
- I think that there is a conflict because the module also tries to use Timer 0 or Timer 1 here
- so somehow we should tell Arduino to use Timer2 on his digital pin13, does someone know how to do it?

I saw your code much more earlier on Github.
Ever since than i am having it. Several months or so.
But didn't have enough time to test it.
That's for the code without your latest addition.
I am interested in adding LCD on it and make it functional.
But i am not skilled avr programmer yet. I can only write simple things.
Playing with interrupts is the hardest part for me, still not learned that well.
And i don't have nRF8001.
I have 6pcs nRF24l01 and 2 pcs ESP8266MOD AI THINKER.
Not sure if some of those is suitable for the task you want?
I tested so far only nRF24l01 and it works pretty straightforward.
ESP8266 is quite different beast... demands more serious effort.

[ivconic]

I you don't post the code of your failed attempt we'll think you have made no attempt at all. It seems you're just trying to have us work for you for free.

I downloaded code from the link and it is compiling well in IDE.
Or just copy&paste code from post to IDE and you will see it.

[ivconic]

For example, i used nRF24l01, one on MEGA and another on NANO and connected them successfully.
Tested the range and maximum i got is 15 meters indoor, from one room to another, 3 walls in between.
Since nRF24l01 is cheap; maybe it can be used instead nRF8001 ??
Here is the example code that i used:

[TreasureHunter]

I saw your code much more earlier on Github.
Ever since than i am having it. Several months or so.
But didn't have enough time to test it.
That's for the code without your latest addition.
I am interested in adding LCD on it and make it functional.
But i am not skilled avr programmer yet. I can only write simple things.
Playing with interrupts is the hardest part for me, still not learned that well.
And i don't have nRF8001.
I have 6pcs nRF24l01 and 2 pcs ESP8266MOD AI THINKER.
Not sure if some of those is suitable for the task you want?
I tested so far only nRF24l01 and it works pretty straightforward.
ESP8266 is quite different beast... demands more serious effort.

[ATTACH]36171[/ATTACH]

Yes this is not my code, this is from a someone on the Arduino forum, who made this in 2013. Than I wanted to add a bluetooth module to it. I saw you attachment in the other comment, sadly its not containing these timer/interrupt stuff that I need.
The problem is not attaching the module, because with the test code it works. The problem is that the timers and interrups are in a conflict I think..

[ivconic]

Ok now i understand.
And what is with smartphone application?

[TreasureHunter]

well yes, the smartphone app is mine, but you can download an other app that was made by Nordic Semiconductor:
https://play.google.com/store/apps/d...semi.nrfUARTv2

With this you can connect to bluetooth devices and send/receive data.

On the topic:
I made some research and I found a good website with good explanation of timers, you can read them here:
http://maxembedded.com/2011/06/avr-timers-timer2/

Still haven't managed to make this work thou.. If there is az Arduino pro who could help, the price is still 25 euro

[ivconic]

well yes, the smartphone app is mine, but you can download an other app that was made by Nordic Semiconductor:
https://play.google.com/store/apps/d...semi.nrfUARTv2

With this you can connect to bluetooth devices and send/receive data.

On the topic:
I made some research and I found a good website with good explanation of timers, you can read them here:
http://maxembedded.com/2011/06/avr-timers-timer2/

Still haven't managed to make this work thou.. If there is az Arduino pro who could help, the price is still 25 euro

Thanks for the link.