Attemp to integrate sonar (ultrasonic sensor)

[Olaf.J]

Hi,

has anybody successfully implemented this code for the Atmega 2560 (Flyduino)? I think, I will get it to use the Trigger-Pin, but I have really no idea, how to modify the code for using the echo-pin with interrupts. I'm using 8-channel transmitter/receiver, so I think the pins PK0 - PK7 are already in use. So I thought, I could use Pin PF5 (analog pin 5), hope that this is the Pin "input5" at the flyduino board...

[Olaf.J]

Hi, I think I've got it. It was a little bit difficult because of no experience with arduino, but it seems to work now with the Flyduino (Atmega2560):

In the def.h, I defined the following:

Code: Select all

/* Pin to interrupt map:
* PCINT 16-23 = PCIE2 = pcmsk2 = PCINT2_vect
* PCINT 0-7 = PCIE0 = pcmsk0 = PCINT0_vect
* PCINT 8-15 = PCIE1 = pcmsk1 = PCINT1_vect
*/

#if defined MEGA
 #if defined(HCSR04)
  #define SONAR 1
  #define HCSR04_TriggerPin 12
  #define HCSR04_TriggerPin_PINMODE_OUT            pinMode(HCSR04_TriggerPin,OUTPUT);
  #define HCSR04_TriggerPin_PIN_HIGH           PORTB |= 1<<6;
  #define HCSR04_TriggerPin_PIN_LOW            PORTB &= ~(1<<6);
  #define HCSR04_EchoPin 11
  #define HCSR04_EchoPin_PINMODE_IN             pinMode(HCSR04_EchoPin,INPUT);
  #define HCSR04_EchoPin_PCINT  PCINT5
  #define HCSR04_EchoPin_PCICR   PCICR |= (1<<PCIE0); // PCINT 0-7 belong to PCIE0
  #define HCSR04_EchoPin_PCMSK   PCMSK0 = (1<<HCSR04_EchoPin_PCINT); // Mask Pin PCINT5 - all other PIns PCINT0-7 are not allowed to create interrupts!
  #define HCSR04_EchoPin_PCINT_vect    PCINT0_vect  // PCINT0-7 belog PCINT0_vect
  #define HCSR04_EchoPin_PIN  PINB  // PCINT0-7 belong to PINB
 #else
  #define SONAR 0
 #endif
#else
 #define SONAR 0
#endif

In the Sensors I used this code:

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/////////////////////////////////////////
// ************************************************************************************************************
// HC-SR04 Ultrasonic Sonar
// ************************************************************************************************************

#if defined(HCSR04)

volatile unsigned long HCSR04_startTime = 0;
volatile unsigned long HCSR04_echoTime = 0;
volatile static int32_t  tempSonarAlt=0;

void Sonar_init()
{
  HCSR04_EchoPin_PCICR;
  HCSR04_EchoPin_PCMSK;
  HCSR04_EchoPin_PINMODE_IN;
  HCSR04_TriggerPin_PINMODE_OUT;
  Sonar_update();
}

// EchoPin will change to high signalize beginning
// and back to low after 58*cm us
// First interrupt is needed to start measurement, second interrupt to calculate the distance


ISR(HCSR04_EchoPin_PCINT_vect) {
  if (HCSR04_EchoPin_PIN & (1<<HCSR04_EchoPin_PCINT)) {            //indicates if the EchoPin is at a high state
    HCSR04_startTime = micros();
  }
  else {
    HCSR04_echoTime = micros() - HCSR04_startTime;
    if (HCSR04_echoTime <= 17400)                                  // maximum = 3 meter
      tempSonarAlt = HCSR04_echoTime / 58;
    else
      tempSonarAlt = 9999;
  }
}

void Sonar_update()
{
    SonarAlt=tempSonarAlt;
    static int32_t sonarTempDistance=0;
    sonarTempDistance = (sonarTempDistance - (sonarTempDistance >> 3)) + SonarAlt;
    SonarAlt= sonarTempDistance >> 3;
    debug4=SonarAlt;
    HCSR04_TriggerPin_PIN_LOW;
    delayMicroseconds(2);
    HCSR04_TriggerPin_PIN_HIGH;
    delayMicroseconds(10);
    HCSR04_TriggerPin_PIN_LOW;
}

#endif

Now, the height in cm is shown in debug4 in multiwii gui

AltHold not yet tested...

[Olaf.J]

Hi,

Sonar-Results are very good - about 99% of the altitude-values of the sonar are valid

But altitude control is not really good. Before mixing sonar and baro, I first want to get a stable alt-control only with sonar. But the copter is oscillating all the time. If I increase P to maximum, the copter is shooting into the air a few meters, followed by falling down to earth. If I decrease P, the copter will also oscillate but with lower amplitude. I think, this is also, because the battery gets lower all the time, so you had to increase the "initialThrottleHold" - but I see no chance to calculate this value on the fly

Has anybody running the sonar with good alt-hold without mixing sonar and baro at low height? Which code is working fine for this?

[noobee]

Hi,

Sonar-Results are very good - about 99% of the altitude-values of the sonar are valid

But altitude control is not really good. Before mixing sonar and baro, I first want to get a stable alt-control only with sonar. But the copter is oscillating all the time. If I increase P to maximum, the copter is shooting into the air a few meters, followed by falling down to earth. If I decrease P, the copter will also oscillate but with lower amplitude. I think, this is also, because the battery gets lower all the time, so you had to increase the "initialThrottleHold" - but I see no chance to calculate this value on the fly

Has anybody running the sonar with good alt-hold without mixing sonar and baro at low height? Which code is working fine for this?

have you tried in increasing d at the same time (to a more negative value) with slightly higher p?

[sandmen]

@Olaf.J
I can confirm that your code work's.
Altitude not tested
Thank you

[Olaf.J]

have you tried in increasing d at the same time (to a more negative value) with slightly higher p?

No, not yet. Unfortunately it's raining and windy at the moment - cannot try it any more today. I'll try this as soon as possible.
Thanks for the tip.

[penpen77]

it's seems the tintywire lib needed for i2cshield has been moved out the orignal repository, so i put the files here

[ziojos]

Hi,

Sonar-Results are very good - about 99% of the altitude-values of the sonar are valid

But altitude control is not really good. Before mixing sonar and baro, I first want to get a stable alt-control only with sonar. But the copter is oscillating all the time. If I increase P to maximum, the copter is shooting into the air a few meters, followed by falling down to earth. If I decrease P, the copter will also oscillate but with lower amplitude. I think, this is also, because the battery gets lower all the time, so you had to increase the "initialThrottleHold" - but I see no chance to calculate this value on the fly

Has anybody running the sonar with good alt-hold without mixing sonar and baro at low height? Which code is working fine for this?

Hi Olaf, I have integrated the SR04 In quite the same way, I have solid result 4-450 cm on an Arduino with only Sonar but on MWii (motor OFF) I have two case:

With RC Radio off I have good data from 4 to 230 cm with rare spikes
Whith RC Radio on I have the the same range but more spikes

I don't understand why in MWii framework the sonar do worse, may be digital noise or power stabilizzation

I use pin 12 to trigger the sonar and pin 4 to echo Interrup, I have added a condenser (100uF) on SR04 power and this gave better results but some spike remain and I have programmed a simple anti-spike,

The sonar work very well in fly from 0 to 2 mt on solid ground , on grass I have less than 2 mt (variable).
To avoid the Hula Hop you need the derivative term (on altitude speed) to brake the oscillation

ciao

[Olaf.J]

To avoid the Hula Hop you need the derivative term (on altitude speed) to brake the oscillation

Hi, "derivative" is the D-Parameter, right? I'll try this - had removed it, because I didn't understood the D-calculation of the baro-control of MWii 2.0, but I implemented it for sonar now - but not tested yet due to weather...

[ziojos]

To avoid the Hula Hop you need the derivative term (on altitude speed) to brake the oscillation

Hi, "derivative" is the D-Parameter, right? I'll try this - had removed it, because I didn't understood the D-calculation of the baro-control of MWii 2.0, but I implemented it for sonar now - but not tested yet due to weather...

Right

[Olaf.J]

Hi zjojos and noobee,

thanks for your info about the D-parameter - I successfully implemented it and found suitable parameters for PID. When hoovering, the height is hold pretty good, if I move the copter, it first goes down 50-80 cm and then goes up to the target-height slowly. When stopping, it first goes up 50-80 cm and then back to the target-height. I think, the main reason for this is the weight of the copter - the total flight-weight is 1435 g. So everything looks fine at the moment

[sandmen]

@Olaf,
do you want to share your implementation?
Thanks
Peter

[Olaf.J]

@Olaf,
do you want to share your implementation?
Thanks
Peter

Hi, it's not yet ready (it's sonar-mode only without mixing baro at the moment and I use a fix height of 180 cm at the moment, instead of height at activating), but if you want to test it already, here's the modified code for flyduino (atmega2560):

def.h - the pins should be changed to pin 9 for trigger and pin 10 for echo for compatibility-reasons (flyduino connection diagram from 13/6/11), but I haven't implemented that yet.

Code: Select all

/* Pin to interrupt map:
* PCINT 16-23 = PCIE2 = pcmsk2 = PCINT2_vect
* PCINT 0-7 = PCIE0 = pcmsk0 = PCINT0_vect
* PCINT 8-15 = PCIE1 = pcmsk1 = PCINT1_vect
*/

#if defined MEGA
#if defined(HCSR04)
  #define SONAR 1
  #define HCSR04_TriggerPin 12 // should be modified to 9 in next version
  #define HCSR04_TriggerPin_PINMODE_OUT            pinMode(HCSR04_TriggerPin,OUTPUT);
  #define HCSR04_TriggerPin_PIN_HIGH           PORTB |= 1<<6;  // should be modified for pin 9 in next version
  #define HCSR04_TriggerPin_PIN_LOW            PORTB &= ~(1<<6);   // should be modified for pin 9 in next version
  #define HCSR04_EchoPin 11     // should be modified to 10 in next version
  #define HCSR04_EchoPin_PINMODE_IN             pinMode(HCSR04_EchoPin,INPUT);
  #define HCSR04_EchoPin_PCINT  PCINT5     // should be modified for pin 10 in next version
  #define HCSR04_EchoPin_PCICR   PCICR |= (1<<PCIE0); // PCINT 0-7 belong to PCIE0 
  #define HCSR04_EchoPin_PCMSK   PCMSK0 = (1<<HCSR04_EchoPin_PCINT); // Mask Pin PCINT5 - all other PIns PCINT0-7 are not allowed to create interrupts!
  #define HCSR04_EchoPin_PCINT_vect    PCINT0_vect  // PCINT0-7 belog PCINT0_vect
  #define HCSR04_EchoPin_PIN  PINB  // PCINT0-7 belong to PINB
#else
  #define SONAR 0
#endif
#else
  #define SONAR 0
#endif

config.h

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#define HCSR04

sensors

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// ************************************************************************************************************
// HC-SR04 Ultrasonic Sonar
// ************************************************************************************************************

#if defined(HCSR04)

volatile unsigned long HCSR04_startTime = 0;
volatile unsigned long HCSR04_echoTime = 0;
volatile unsigned long SonarSuccess = 0;
volatile unsigned long SonarFail = 0;
unsigned int HCSR04_current_loops = 0;
volatile static int32_t  tempSonarAlt=0;

// The cycle time is between 3000 and 6000 microseconds
// The recommend cycle period for sonar request should be no less than 40ms -> 40000 microseconds
// A reading every 13 loops (40000 / 3000 aprox)
unsigned int HCSR04_loops = 13;

void Sonar_init()
{
  HCSR04_EchoPin_PCICR;
  HCSR04_EchoPin_PCMSK;
  HCSR04_EchoPin_PINMODE_IN;
  HCSR04_TriggerPin_PINMODE_OUT;
  Sonar_update();
}

// EchoPin will change to high signalize beginning
// and back to low after 58*cm us
// First interrupt is needed to start measurement, second interrupt to calculate the distance


ISR(HCSR04_EchoPin_PCINT_vect) {
  //
  // Here is a routine missing, to check, if the interrupt was raised for echo pin - not needed at the moment, because we don't have any interrupts
  // for this interrupt group, but maybe later
  //
  if (HCSR04_EchoPin_PIN & (1<<HCSR04_EchoPin_PCINT)) {            //indicates if the EchoPin is at a high state
    HCSR04_startTime = micros();
  }
  else {
    HCSR04_echoTime = micros() - HCSR04_startTime;
    if (HCSR04_echoTime <= 25000)                                  // maximum = 4,31 meter - 30000 us means out of range
      tempSonarAlt = HCSR04_echoTime / 58;
    else
      tempSonarAlt = 9999;
  }
}

void Sonar_update()
{
  HCSR04_current_loops++;
  if ((HCSR04_current_loops >= HCSR04_loops) && baroMode) {
    HCSR04_current_loops = 0;
    LastSonarAlt = SonarAlt;
    SonarAlt = tempSonarAlt;
    debug2 = SonarAlt;
    if (SonarAlt < 500) {
      SonarSuccess += 1;  // count successful readings of height
      debug3 = SonarSuccess;
    } else {
      SonarAlt = 9999;
      SonarFail += 1;  // count failed readings of heigt
      debug4 = SonarFail;
    }

    // create a trigger pulse for 10 us
    HCSR04_TriggerPin_PIN_LOW;
    delayMicroseconds(2);
    HCSR04_TriggerPin_PIN_HIGH;
    delayMicroseconds(10);
    HCSR04_TriggerPin_PIN_LOW;
  }
}

#endif

imu

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void getEstimatedAltitude(){
  uint8_t index;
  static uint32_t deadLine = INIT_DELAY;

  static int16_t BaroHistTab[BARO_TAB_SIZE];
  static int8_t BaroHistIdx;
  static int32_t BaroHigh,BaroLow;
  int32_t temp32;
  int16_t last;
  
  if (currentTime < deadLine) return;
  deadLine = currentTime + UPDATE_INTERVAL; 

  //**** Alt. Set Point stabilization PID ****
  //calculate speed for D calculation
  last = BaroHistTab[BaroHistIdx];  // letzter Wert aus BaroHistTab
  BaroHistTab[BaroHistIdx] = BaroAlt/10;  // durch 10 teilen
  BaroHigh += BaroHistTab[BaroHistIdx]; 
  index = (BaroHistIdx + (BARO_TAB_SIZE/2))%BARO_TAB_SIZE;
  BaroHigh -= BaroHistTab[index];
  BaroLow  += BaroHistTab[index];
  BaroLow  -= last;

  BaroHistIdx++;
  if (BaroHistIdx == BARO_TAB_SIZE) BaroHistIdx = 0;

  BaroPID = 0;

  //D
  #ifdef SONAR
    temp32 = D8[PIDALT]*(SonarAlt-LastSonarAlt) / 40; // example climbed from 150 to 170 cm, D=7 -> temp32=7*(170-150)/40=3,5 -> BaroPID = -3,5
  #else
    temp32 = D8[PIDALT]*(BaroHigh - BaroLow) / 40;
  #endif
  BaroPID-=temp32;

  EstAlt = BaroHigh*10/(BARO_TAB_SIZE/2);

  // Olaf
  // Use sonar to hold at 180 cm instead of last height
  
  #ifdef SONAR
    if (SonarAlt < 500)
      temp32 = 180 - SonarAlt;
    else
      temp32 = 0;  // if no valid result from SONAR -> no P-Value!
  #else
    temp32 = AltHold - EstAlt;
    if (abs(temp32) < 10 && abs(BaroPID) < 10) BaroPID = 0;  //remove small differences to reduce noise near zero position
  #endif

  
  //P
  BaroPID += P8[PIDALT]*constrain(temp32,(-2)*P8[PIDALT],2*P8[PIDALT])/100;  // temp32 auf should be for example in range +- 32 for P=16 (= 1.6 in GUI)   
  // example: climbed from 150 cm to 170 cm, target height: 180 cm, P=40
  // BaroPID += 40*(180-170)/100 = increase BaroPID for 4,0
  
  BaroPID = constrain(BaroPID,-150,+150); //sum of P and D should be in range 150

  //I
  errorAltitudeI += temp32*I8[PIDALT]/50; //example: height is 170 cm, target heigth 180 cm, I = 15 (0.015 in GUI) -> 10*15/50 = increase for 3
  errorAltitudeI = constrain(errorAltitudeI,-30000,30000);
  temp32 = errorAltitudeI / 500; //I in range +/-60 // this is a long term PID - will for example compensate decreasing battery voltage
  BaroPID+=temp32;
}

MultiWii_2_0

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static int32_t  SonarAlt;
static int32_t  LastSonarAlt;

[...]

      case 1:
        taskOrder++; 
        #if BARO
          Baro_update();  
          #if defined(SONAR)
          Sonar_update();  
          #endif 
          break;
        #endif

I began with the standard values with not really good success. So I increased the D-value to 20, this made it much more stable. Then I increase P still it began to oscillate (slowly) and then decreased it (I think it's 3 at the moment). I increased the I-value slightly from 0.015 to 0.020, otherwise the copter came down sloswly, when the battery voltage decreased.

If the code is ready incl. baro-mixing, I will share the code again of course, if it's of interest for anybody. I'm not sure at the moment, if the baro-PID-values and the sonar-PID-values can be the same or if we need different PIDs for baro and sonar, because baro has (at least at my copter) much more noise.

[nicodh]

Hi Olaf,
About baro mixing, i remember in arducopter, they use a condition to use the baro or the sonar. Because the sonar is usable only if distance to obstacle is less than (let's say 6 meters) you can use the sonar reading in the loops when you are at a maximum of that altitude, other wise you use the baro.

[copterrichie]

If anyone is interested, $2.80US

Ultrasonic Module HC-SR04

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... SS:US:1123

[bverissimo]

I use an Arduino ONE that has an output of 3.3V. I think the Arduino Pro Mini (5V version) also has an output of 3.3V that can be used instead of pin 12.

If you do not have that output you will have to use a LM117 to pass the 5V to 3.3V, as illustrated in the diagrams.

Hi Vallekano ,

Thanks for your help.

I follow your steps, Now can get altitude reading from DEBUG3, How can I get altitude hold ? Next for autolanding...

My QuadX , wmp + HCSR04, No Baro.

Hi , how did you manage to conect the HC-Sr04 on the arduino pro mini ..wich pins you use ?
And please can o send me yyour code try to edit mine but nothing ..many thanks in advance ..

[didlawowo69]

no one have a video of demo ?

[Dehas]

@ penpen77: I try to use your code and i have this error "smartDigitalWrite' was not declared in this scope" in arduino 1.0.

[Katch]

Any updates with this?

Seeing a lot of other dev using i2c/secondary MCU set ups but would like to try my HC-SR04 on my 2560 Megapirate board. It already has a header for sonar so I'll trace the pins and work out what they are connected to and see about applying this code.

If it follows Megapirate_ng code specs it should be pins 9 and 10

[copterrichie]

I really want to give this a try, any updates?

[copterrichie]

@ penpen77: I try to use your code and i have this error "smartDigitalWrite' was not declared in this scope" in arduino 1.0.

If my memory serves me right, the smartDigitalwrite is a special library but I believe you can use digitalWrite().

viewtopic.php?f=7&t=1033&start=20

[Lapino]

push
any updates regarding implementation of HC-SR04 sonar?

[penpen77]

smartDigitalWrite is just digitalwrite without all check/test, comment unnecessary lines, that's all. You can use digitalWrite, it's just mater of binary size.

Lapino, once you have an i2c wrapper for hcsr04, the implementation is done, just use code of other i2c sonar.

[Lapino]

So I've to build a ATTINY4313 Sonar device or how can I realize an i2c wrapper? Must be some kind of hardware am I right?

[Cronalex]

I would use this sonar Maxbotix LV-EZ0 you can?

[Tommie]

So I've to build a ATTINY4313 Sonar device or how can I realize an i2c wrapper? Must be some kind of hardware am I right?

Right. And it's not that difficult: viewtopic.php?f=8&t=1549&p=16225#p16225

[wilco1967]

Just managed to get the HCSR04 working using the TinyGPS route in altitude hold mode.
I'm using the modified BARO PID code derived from Olaf.J 's solution posted earlier in this tread....

I initially wanted to use my Mega, and directly wire the sonar to the Flyduino, but I could not get Olaf's code compiled, as it seems to interfere with the recently added TinyGPS code in dev20120606. And I'm only starting to figure out how to program the Arduino, so not good enough to figure it out myself (yet)...
I assume Olaf used the bare 2.0 code (or even earlier) for the HCSR04 to Mega connection, and I'm using dev20120606.

With the TinyGPS route, the Sonar is working,, and I used the basis of Olaf Baro code (the getEstimatedAltitude part that goes in IMU) to get altitude hold....

Code: Select all

//wilco
void getEstimatedAltitude(){
  uint8_t index;
  static uint32_t deadLine = INIT_DELAY;

  static int16_t BaroHistTab[BARO_TAB_SIZE];
  static int8_t BaroHistIdx;
  static int32_t BaroHigh,BaroLow;
  int32_t temp32;
  int16_t last;
  
  if (currentTime < deadLine) return;
  deadLine = currentTime + UPDATE_INTERVAL; 

  //**** Alt. Set Point stabilization PID ****
  //calculate speed for D calculation
  last = BaroHistTab[BaroHistIdx];  // letzter Wert aus BaroHistTab
  BaroHistTab[BaroHistIdx] = BaroAlt/10;  // durch 10 teilen
  BaroHigh += BaroHistTab[BaroHistIdx]; 
  index = (BaroHistIdx + (BARO_TAB_SIZE/2))%BARO_TAB_SIZE;
  BaroHigh -= BaroHistTab[index];
  BaroLow  += BaroHistTab[index];
  BaroLow  -= last;

  BaroHistIdx++;
  if (BaroHistIdx == BARO_TAB_SIZE) BaroHistIdx = 0;

  if (SonarAlt < 0) return; //wilco.... -1 = not a correct reading, Exit this routine and leave BaroPID at last value, so copter does not jump.
  BaroPID = 0;

  //D
  #ifdef SONAR
    temp32 = conf.D8[PIDALT]*(SonarAlt-LastSonarAlt) / 40; // example climbed from 150 to 170 cm, D=7 -> temp32=7*(170-150)/40=3,5 -> BaroPID = -3,5
  #else
    temp32 = conf.D8[PIDALT]*(BaroHigh - BaroLow) / 40;
  #endif 
  BaroPID-=temp32;

  EstAlt = BaroHigh*10/(BARO_TAB_SIZE/2);

  // Olaf
  // Use sonar to hold at 180 cm instead of last height
  
  #ifdef SONAR
    if (SonarAlt < 500)
      temp32 = 100 - SonarAlt;
    else
      temp32 = 0;  // if no valid result from SONAR -> no P-Value!
  #else
    temp32 = AltHold - EstAlt;
    if (abs(temp32) < 10 && abs(BaroPID) < 10) BaroPID = 0;  //remove small differences to reduce noise near zero position
  #endif

  
  //P
  BaroPID += conf.P8[PIDALT]*constrain(temp32,(-2)*conf.P8[PIDALT],2*conf.P8[PIDALT])/100;  // temp32 auf should be for example in range +- 32 for P=16 (= 1.6 in GUI)   
  // example: climbed from 150 cm to 170 cm, target height: 180 cm, P=40
  // BaroPID += 40*(180-170)/100 = increase BaroPID for 4,0
  
  BaroPID = constrain(BaroPID,-150,+150); //sum of P and D should be in range 150

  //I
  errorAltitudeI += temp32*conf.I8[PIDALT]/50; //example: height is 170 cm, target heigth 180 cm, I = 15 (0.015 in GUI) -> 10*15/50 = increase for 3
  errorAltitudeI = constrain(errorAltitudeI,-30000,30000);
  temp32 = errorAltitudeI / 500; //I in range +/-60 // this is a long term PID - will for example compensate decreasing battery voltage
  BaroPID+=temp32;
}
//wilco

I'm running a normal 328P on the multiwii, and a Attiny4313 to connect the HCSR04 (No GPS on this copter). I've temporarily connected all to my quad, and it is holding altitude pretty good.

Weather is very windy at the moment, and I can only fly around the house, where there is a lot of turbulence, but still, it manages quite OK...

made a small modification that if the sonar data is faulty/out of range (-1), the BaroPID is not reset to zero, (or even worse, run through the PID algorithm), but simply left at the last state.... That way, the copter does not jump if momentarily loosing the sonar distance (which happens quite often).

I need to activate Baro, even though my quad does not have a baro (just sonar now), otherwise the baroPID routine will not run.... but time permitting, I'm going to have a shot at improving that.... Right now I get lots of I2C errors, due to the missing Baro... (zero errors if no baro defined, so TinyGPS is working perfect).
And if I'm feeling very lucky, I might even attempt to integrate Baro + Sonar in the same routine.....
These are my first attempts to actually change something more that the config.h.... so please bare with me....

But I still would like to go the route with directly connected HCSR04 to the Flyduino.... Any progress on that with the latest dev as a base ?
I think we're getting close to a working Sonar hold.

Wilco

[Tommie]

Can you please publish a patch relative to the latest svn _shared version? I'd be delighted to include it into my git branch.

[Cronalex]

I would use this sonar Maxbotix LV-EZ0 you can?

up

[Bazed]

Has anyone had issues with the TinyWire library in the TinySonarI2C code? I'm not sure, but it looks like the tinywire libs have been updated, now it's called tinywireS and tinywireM (slave & master).
Been trying to change the original code in the tinysonari2c to work with the new libs, but no luck so far. Anyone else having this problem?

[Gaijin]

Just pIcked up a nice ready made AT328 based I2C module, would it be difficult to modify the ATTiny code to run on it?

I have an HC-SRF04 kicking about, between them it could make for a very simple to build and low cost I2C sonar sensor, any thoughts

http://www.rctimer.com/index.php?gOo=goods_details.dwt&goodsid=762&productname=

[xpix]

With the TinyGPS route, the Sonar is working,, and I used the basis of Olaf Baro code (the getEstimatedAltitude part that goes in IMU) to get altitude hold....

I'm running a normal 328P on the multiwii, and a Attiny4313 to connect the HCSR04 (No GPS on this copter). I've temporarily connected all to my quad, and it is holding altitude pretty good.

Hello Wilco, i put ur patch in the new MW 2.1 in my IMU Module. The compiler dont like 'SonarAlt' ... i renamed in ur Code to 'sonarAlt'. What is happend with 'lastSonarAlt' in ur Code, u dont use it (everytime on 0) or u refresh this magic in ur Code?

My Solution:

Code: Select all

  #ifdef SONAR
    if (sonarAlt < 500){
      lastSonarAlt = sonarAlt; // save Alt for later
      temp32 = 100 - sonarAlt;
    } else {
      temp32 = 0;  // if no valid result from SONAR -> no P-Value!
    }
  #else
    temp32 = AltHold - EstAlt;
    if (abs(temp32) < 10 && abs(BaroPID) < 10) BaroPID = 0;  //remove small differences to reduce noise near zero position
  #endif

in IMU, is this so correct?

[dr.tom]

Just pIcked up a nice ready made AT328 based I2C module, would it be difficult to modify the ATTiny code to run on it?

I have an HC-SRF04 kicking about, between them it could make for a very simple to build and low cost I2C sonar sensor, any thoughts

http://www.rctimer.com/index.php?gOo=goods_details.dwt&goodsid=762&productname=

I like the idea, I've build an attiny+sonar just for curiosity, but MWC code didn't have real use for it.
but some day when it will use it for althold, this mod with rctimer 328p would be plug&play,
easier to get, connect and program and cleaner look to integrate to other models...

+1

[scanman]

Hello, i have read through all the multiwii posts on sonar and i still dont really know where to start, what sonar to buy (they seem to range from $60 to $6), what code i need to modify , and where i need to wire up the sonar. would someone be so kind as to post a few simple steps to getting started?
Note: i have got the i2C nav board from rc timer wired up to a GPS using EOSBandi's code , as discussed at length in the GPS threads, so i am wondering how to connect the sonar? Do I need another i2c board? What code do i flash onto that board? do I wire it up to the same I2C port as the GPS i2C board?
Any tips would be useful before i get started!

I2C nav board link: http://www.rctimer.com/index.php?gOo=go ... oductname=

[penpen77]

i'm using this code for my sr04 sonar/baro alt mode, juste mixing both and altering "EstAlt" as in megapirate/arducopter. No tilt correction or advanced stuff, but works fine, alt hold logic isn't altered neither code for sonar device. With a good tuned Alt hold pids value, it's working perfectly.

in MultiWii_2_1.ino

Code: Select all

//add in global decl
static int32_t BaroHome;
static int8_t BaroHome_set=0;

in IMU.ino

Code: Select all

//replace "EstAlt = BaroHigh*10/(BARO_TAB_SIZE/2);" by 

#if SONAR
  int32_t tempBaro = BaroHigh*10/(BARO_TAB_SIZE/2);
  
  if(!f.ARMED && f.BARO_MODE) { //init offset
    BaroHome_set = 1;
    BaroHome = tempBaro;
  }
  
  if(f.ARMED && BaroHome_set ==0) { // if forgotten
    BaroHome_set = 1;
    BaroHome = tempBaro;
  }

  //mix baro/sonar    
  if(SonarAlt<SONAR_SONARFULL) {
    EstAlt = BaroHome+sonarAlt;
  }
  else if(SonarAlt>=SONAR_SONARFULL && SonarAlt <SONAR_BAROFULL) {
    float fade = (float)(SONAR_BAROFULL-sonarAlt)/(SONAR_BAROFULL-SONAR_SONARFULL);
    fade = constrain(fade, 0.0, 1.0);
    EstAlt = (BaroHome+sonarAlt)*fade + tempBaro*(1-fade);
  } else {
    EstAlt = tempBaro;
  }
#else
    EstAlt = BaroHigh*10/(BARO_TAB_SIZE/2);
#endif

and in config.h

Code: Select all

     //mixing values between sonar and baro
     #define SONAR_SONARFULL 150 //full sonar reading before this point (cm)
     #define SONAR_BAROFULL 300 //full baro reading after this point (cm)

baro offset is done by activating baro mode in non armed mode or at the first arming action.

[crazyal]

If anybody is interested in using the HC-sr04 with the i2c-gps-nav, I have added some code, so the i2c-gps reads the sonar and the data can be read via the I2C bus.
It basically works the same as the tyiny-gps with sonar.
The code is on github: http://github.com/luggi
@penpen77 what pid values are you using ?

[Magnetron]

Is possible to integrate dyp-me007?

[penpen77]

@crazyal

1.2/0.0/14, i've noticed playing more with D param has better effect than playing with P,I like other mode.

@magnetron

dyp-me007 works like sr04

[Magnetron]

I have one dyp-me007v2 and a mega2560. What pin I must use to connect to?

[penpen77]

updated code for new alt hold code (for MS561101BA)

works fine (on pos hold and at low speed), for better result, perform your althold pid tuning around 50% of sonar/baro fusion altitude.
at "high" speed, the baro-only EstAlt could increase if not wind-protected, and sonar/baro fusion could produce wrong alt reading, so be carefull...

Code: Select all

void getEstimatedAltitude(){
  static uint32_t deadLine = INIT_DELAY;

  static int16_t baroHistTab[BARO_TAB_SIZE];
  static int8_t baroHistIdx;
  static int32_t baroHigh;
 

  if (abs(currentTime - deadLine) < UPDATE_INTERVAL) return;
  uint16_t dTime = currentTime - deadLine;
  deadLine = currentTime;
 

  //**** Alt. Set Point stabilization PID ****
  baroHistTab[baroHistIdx] = BaroAlt/10;
  baroHigh += baroHistTab[baroHistIdx];
  baroHigh -= baroHistTab[(baroHistIdx + 1)%BARO_TAB_SIZE];
 
  baroHistIdx++;
  if (baroHistIdx == BARO_TAB_SIZE) baroHistIdx = 0;

  
#if SONAR
  int32_t tempBaro = EstAlt*0.6f + (baroHigh*10.0f/(BARO_TAB_SIZE - 1))*0.4f;
  
  if(!f.ARMED && f.BARO_MODE) { //init offset
    BaroHome_set = 1;
    BaroHome = tempBaro;
  }
  
  if(f.ARMED && BaroHome_set ==0) { // if forgotten
    BaroHome_set = 1;
    BaroHome = tempBaro;
  }

  //mix baro/sonar    
  if(SonarAlt<SONAR_SONARFULL) {
    EstAlt = BaroHome+SonarAlt;
  }
  else if(SonarAlt>=SONAR_SONARFULL && SonarAlt <SONAR_BAROFULL) {
    float fade = (float)(SONAR_BAROFULL-SonarAlt)/(SONAR_BAROFULL-SONAR_SONARFULL);
    fade = constrain(fade, 0.0, 1.0);
    EstAlt = (BaroHome+SonarAlt)*fade + tempBaro*(1-fade);
  } else {
    EstAlt = tempBaro;
  }
#else

    EstAlt = EstAlt*0.6f + (baroHigh*10.0f/(BARO_TAB_SIZE - 1))*0.4f;
    
#endif
  
  //P
  int16_t error = constrain(AltHold - EstAlt, -300, 300);
  error = applyDeadband16(error, 10); //remove small P parametr to reduce noise near zero position
  BaroPID = constrain((conf.P8[PIDALT] * error / 100), -150, +150);
 
  //I
  errorAltitudeI += error * conf.I8[PIDALT]/50;
  errorAltitudeI = constrain(errorAltitudeI,-30000,30000);
  BaroPID += (errorAltitudeI / 500); //I in range +/-60
 
 
  // projection of ACC vector to global Z, with 1G subtructed
  // Math: accZ = A * G / |G| - 1G
  float invG = InvSqrt(isq(EstG.V.X) + isq(EstG.V.Y) + isq(EstG.V.Z));
  int16_t accZ = (accLPFVel[ROLL] * EstG.V.X + accLPFVel[PITCH] * EstG.V.Y + accLPFVel[YAW] * EstG.V.Z) * invG - acc_1G;
  //int16_t accZ = (accLPFVel[ROLL] * EstG.V.X + accLPFVel[PITCH] * EstG.V.Y + accLPFVel[YAW] * EstG.V.Z) * invG - 1/invG;
  accZ = applyDeadband16(accZ, ACC_Z_DEADBAND);
  
  static float vel = 0.0f;
  static float accVelScale = 9.80665f / acc_1G / 10000.0f;
  
  // Integrator - velocity, cm/sec
  vel+= accZ * accVelScale * dTime;
  
  static int32_t lastBaroAlt = EstAlt;
  float baroVel = (EstAlt - lastBaroAlt) / (dTime/1000000.0f);
  baroVel = constrain(baroVel, -300, 300); // constrain baro velocity +/- 300cm/s
  baroVel = applyDeadbandFloat(baroVel, 10); // to reduce noise near zero  
  lastBaroAlt = EstAlt;
  
  // apply Complimentary Filter to keep the calculated velocity based on baro velocity (i.e. near real velocity). 
  // By using CF it's possible to correct the drift of integrated accZ (velocity) without loosing the phase, i.e without delay
  vel = vel * 0.985f + baroVel * 0.015f;
  //vel = constrain(vel, -300, 300); // constrain velocity +/- 300cm/s 
  
  //D
  BaroPID -= constrain(conf.D8[PIDALT] * applyDeadbandFloat(vel, 5) / 20, -150, 150);
}

all depencies are in previous code snippet or alt hold topic last code snippet

This is a "attemp to integrate sonar" topic, not an "early adopting perfectly working feature" topic, you have to know what you are doing, please stop pm/blame me because you crash your stuff...

[Magnetron]

there are new on sonar / baro implementation?
Baro altitude routine only seems to be very responsive.

[KasparsL]

+1,
Is there some news for using HC-SR04 or other?

[janekx]

+1 for HC-SR04

[penpen77]

sr04 and simili works since several months.....

[penpen77]

EDIT: use code snippet instead

full code, based on last build (r1129)

althold with sonar/baro mixed works fine, tested on sr04, dypme007 and tinygps (i dont have i2c native devantech)

current define are for crius/mega board, don't forget to enable once baro mode before arming to set "baro home/zero alt level" (visible in debug[3])

sonar value are mixed before baro lpf, more robust but more "floppy", free to change before/after lpf

BTW, very low althold must be reached by slow going down, not by going up

last thing, ultrasonic doesn't like carpet, dont try inside over a carpet >_<

in config.h

hardware part
SONAR_GENERIC_ECHOPULSE is define for interrupt driven tx/trigger/pulse/echo sonar, pinout ar mapped in def.h (fallow the define)
SONAR_GENERIC_SCALE is the value for converting us to cm (not the same between sr04,me007, etc...
SONAR_GENERIC_MAX_RANGE is the range of sonar (used for validating reading, which now i remembered i've forgotten to test in code.... be carefull, add a test with 9999 value)

baro/sonar mixing part (assuming sonarAlt is correctly provided by hardware)
SONAR_TILT_CORRECTION define if sonar reading wil be corrected during tilting quad (use triggo, ressources hungry, could be optimized)
SONAR_BARO_FUSION activating fusion
SONAR_BARO_FUSION_LC low cut, below this value, cm, only sonar reading are used for EstAlt/AltHold
SONAR_BARO_FUSION_HC high cut, above this value, cm, only baro are used
SONAR_BARO_FUSION_RATIO specify amount of each sensor are used (sonar mult prior), if 0.0, its proportional, close to LC, it's more sonar, close to HC, more baro

there aren't really many heavy modification, but all is here and working so far, so good

[Magnetron]

full code, based on last build (r1129)

althold with sonar/baro mixed works fine, tested on sr04, dypme007 and tinygps (i dont have i2c native devantech)

current define are for crius/mega board, don't forget to enable once baro mode before arming to set "baro home/zero alt level" (visible in debug[3])

sonar value are mixed before baro lpf, more robust but more "floppy", free to change before/after lpf

BTW, very low althold must be reached by slow going down, not by going up

last thing, ultrasonic doesn't like carpet, dont try inside over a carpet >_<

in config.h

hardware part
SONAR_GENERIC_ECHOPULSE is define for interrupt driven tx/trigger/pulse/echo sonar, pinout ar mapped in def.h (fallow the define)
SONAR_GENERIC_SCALE is the value for converting us to cm (not the same between sr04,me007, etc...
SONAR_GENERIC_MAX_RANGE is the range of sonar (used for validating reading, which now i remembered i've forgotten to test in code.... be carefull, add a test with 9999 value)

baro/sonar mixing part (assuming sonarAlt is correctly provided by hardware)
SONAR_TILT_CORRECTION define if sonar reading wil be corrected during tilting quad (use triggo, ressources hungry, could be optimized)
SONAR_BARO_FUSION activating fusion
SONAR_BARO_FUSION_LC low cut, below this value, cm, only sonar reading are used for EstAlt/AltHold
SONAR_BARO_FUSION_HC high cut, above this value, cm, only baro are used
SONAR_BARO_FUSION_RATIO specify amount of each sensor are used (sonar mult prior), if 0.0, its proportional, close to LC, it's more sonar, close to HC, more baro

there aren't really many heavy modification, but all is here and working so far, so good

I would to try it.
A pinout to connect a DYP-ME007 on a Mega2560?

[mahowik]

full code, based on last build (r1129)

althold with sonar/baro mixed works fine, tested on sr04, dypme007 and tinygps (i dont have i2c native devantech)

current define are for crius/mega board, don't forget to enable once baro mode before arming to set "baro home/zero alt level" (visible in debug[3])

Hi penpen!

In general it looks ok, but i propose to add some changes
1) to avoid manual init and keep in mind additional instruction probably make sense to change this

Code: Select all

if(!f.ARMED && f.BARO_MODE) { //init offset
      BaroHome = (baroHigh*10.0f/(BARO_TAB_SIZE - 1));
    }
  
    if(f.ARMED && BaroHome ==0) { // if forgotten
      BaroHome = (baroHigh*10.0f/(BARO_TAB_SIZE - 1));
    } 

to this:

Code: Select all

if(!f.ARMED) { //init offset till motors not armed
      BaroHome = BaroHome*0.9f + (baroHigh*10.0f/(BARO_TAB_SIZE - 1))*0.1f; // play with optimal coef. here
    }

thx-
Alex

[penpen77]

indeed, that was my first impl, but it's doing some probs:
- until copter armed, EstAlt value isn't correct...
- using some OSD (mobidrone for example) firsts reading after startup are used for offset, so if waiting too long for setting barohome, incorrect value are used
- if windy day, it's good to be able to "reset" barohome to avoid crazy value

in my opinion, the best option should be: auto set after XX seconds (delay define) and possibility to override manually barohome stored value
But, that's mean adding again some define (already added a lot for sonar) and mapping an aux statement for set barohome

I'd try giving value at compile time, baro home value int the code, but it was bad idea, readings have too many way of changing (inside, outside, weather, temperature, etc...)

i don't really know what the better to do, but for testing, activating althold once if not armed to store barohome (with the ability to store when arming the first time if forgotten) do the job, and doesn't need to arm for ground testing.

One other impl i've done (not in code here) but usefull, is adding a "buzzing" event if EstAlt is too low, kind of collision alarm since Alt reading is more accurate with sonar. Just some mod with lighting landing code

[mahowik]

indeed, that was my first impl, but it's doing some probs:
- until copter armed, EstAlt value isn't correct...
- using some OSD (mobidrone for example) firsts reading after startup are used for offset, so if waiting too long for setting barohome, incorrect value are used
- if windy day, it's good to be able to "reset" barohome to avoid crazy value

in my opinion, the best option should be: auto set after XX seconds (delay define) and possibility to override manually barohome stored value
But, that's mean adding again some define (already added a lot for sonar) and mapping an aux statement for set barohome

I'd try giving value at compile time, baro home value int the code, but it was bad idea, readings have too many way of changing (inside, outside, weather, temperature, etc...)

i don't really know what the better to do, but for testing, activating althold once if not armed to store barohome (with the ability to store when arming the first time if forgotten) do the job, and doesn't need to arm for ground testing.

One other impl i've done (not in code here) but usefull, is adding a "buzzing" event if EstAlt is too low, kind of collision alarm since Alt reading is more accurate with sonar. Just some mod with lighting landing code

Strange that it's not working for you. Actually it's averaged all time altitude while motors are not armed...

Code: Select all

if(!f.ARMED) { //init offset till motors not armed
      BaroHome = BaroHome*0.9f + (baroHigh*10.0f/(BARO_TAB_SIZE - 1))*0.1f; // play with optimal coef. here
    }

But yes it takes some time for initialization. As I mentioned here new alt hold will take about 10-15 sec to init/stabilize all LPFs and CF...
- wait 10-15 sec after power on OR after ACC calibration... all LPFs, velocity integrator and CF need to be syncronized
During this time light BaroHome LPF also should be stabilized...

Also I'm sure that you know but just for your information on altitudes less then 1..2m there ground effect and baro can give minus 1..2m in measurement and become very unstable with their raw data... Probably it's reason why you was confused with init baro values... According to this to avoid baro ground effect it make sense to set SONAR_BARO_FUSION_LC at least to 150cm and from my experience sonars like dyp-me007 and hc-sr04 gives unstable values after 2..2.5m on the fly because of the acoustic noise form motors and electrical influence from power and ESC cords... so I propose

Code: Select all

      #define SONAR_BARO_FUSION_LC 150 //cm, low cut, below = full sonar
      #define SONAR_BARO_FUSION_HC 250 //cm, high cut, above = full baro

thx-
Alex

[penpen77]

it was just testing values, i've archived my working dir "as is", it's not intented to be working out the box or using perfectly tuned constants