Sketch for Lightning Sensor

[Sparkman]

My radios showed up a few days ago and this is the sketch I'm using:

#include "MySensor.h"  

// the sensor communicates via SPI or I2C. This example uses the SPI interface
#include "SPI.h"
// include Playing With Fusion AXS3935 libraries
#include "PWFusion_AS3935.h"

// setup CS pins used for the connection with the sensor
// other connections are controlled by the SPI library)
int8_t CS_PIN  = 8;
int8_t SI_PIN  = 7;
int8_t IRQ_PIN = 3;                      
volatile int8_t AS3935_ISR_Trig = 0;

// #defines
#define AS3935_INDOORS       1
#define AS3935_OUTDOORS      0
#define AS3935_DIST_DIS      0
#define AS3935_DIST_EN       1
#define AS3935_CAPACITANCE   96      // <-- SET THIS VALUE TO THE NUMBER LISTED ON YOUR BOARD 
// prototypes
void AS3935_ISR();

PWF_AS3935  lightning0(CS_PIN, IRQ_PIN, SI_PIN);

#define CHILD_ID_DISTANCE 1
#define CHILD_ID_INTENSITY 2
MySensor gw;
MyMessage msgDist(CHILD_ID_DISTANCE, V_DISTANCE);
MyMessage msgInt(CHILD_ID_INTENSITY, V_VAR1);

void setup()  
{ 
  gw.begin();

  // Send the sketch version information to the gateway and Controller
  gw.sendSketchInfo("Lightning Sensor", "1.0");

  // Register all sensors to gw (they will be created as child devices)
  gw.present(CHILD_ID_DISTANCE, S_DISTANCE);
  gw.present(CHILD_ID_INTENSITY, S_CUSTOM);
  boolean metric = gw.getConfig().isMetric;

  Serial.begin(115200);
  Serial.println("Playing With Fusion: AS3935 Lightning Sensor, SEN-39001");
  Serial.println("beginning boot procedure....");
  
  // setup for the the SPI library:
  SPI.begin();                            // begin SPI
  SPI.setClockDivider(SPI_CLOCK_DIV4);    // SPI speed to SPI_CLOCK_DIV16/1MHz (max 2MHz, NEVER 500kHz!)
  SPI.setDataMode(SPI_MODE1);             // MAX31855 is a Mode 1 device
                                          //    --> clock starts low, read on rising edge
  SPI.setBitOrder(MSBFIRST);              // data sent to chip MSb first 
  
  lightning0.AS3935_DefInit();                        // set registers to default  
  // now update sensor cal for your application and power up chip
  lightning0.AS3935_ManualCal(AS3935_CAPACITANCE, AS3935_OUTDOORS, AS3935_DIST_EN);
                  // AS3935_ManualCal Parameters:
                  //   --> capacitance, in pF (marked on package)
                  //   --> indoors/outdoors (AS3935_INDOORS:0 / AS3935_OUTDOORS:1)
                  //   --> disturbers (AS3935_DIST_EN:1 / AS3935_DIST_DIS:2)
                  // function also powers up the chip
                  
  // enable interrupt (hook IRQ pin to Arduino Uno/Mega interrupt input: 0 -> pin 2, 1 -> pin 3 )
  attachInterrupt(1, AS3935_ISR, RISING);

  lightning0.AS3935_PrintAllRegs();
  
  // delay execution to allow chip to stabilize.
  delay(1000);

}

void loop()      
{     

  // This program only handles an AS3935 lightning sensor. It does nothing until 
  // an interrupt is detected on the IRQ pin.
  while(0 == AS3935_ISR_Trig){}
 
  // reset interrupt flag
  AS3935_ISR_Trig = 0;
  
  // now get interrupt source
  uint8_t int_src = lightning0.AS3935_GetInterruptSrc();
  if(0 == int_src)
  {
    Serial.println("Unknown interrupt source");
    //gw.send(msgDist.set(999));
    //gw.send(msgInt.set(0));
  }
  else if(1 == int_src)
  {
    uint8_t lightning_dist_km = lightning0.AS3935_GetLightningDistKm();
    uint32_t lightning_intensity = lightning0.AS3935_GetStrikeEnergyRaw();

    Serial.print("Lightning detected! Distance to strike: ");
    Serial.print(lightning_dist_km);
    Serial.println(" kilometers");
    Serial.print("Lightning detected! Lightning Intensity: ");
    Serial.println(lightning_intensity);
    gw.send(msgDist.set(lightning_dist_km));
    gw.send(msgInt.set(lightning_intensity));
  }
  else if(2 == int_src)
  {
    Serial.println("Disturber detected");
    //gw.send(msgDist.set(998));
    //gw.send(msgInt.set(0));
  }
  else if(3 == int_src)
  {
    Serial.println("Noise level too high");
    //gw.send(msgDist.set(997));
    //gw.send(msgInt.set(0));
  }
}

// this is irq handler for AS3935 interrupts, has to return void and take no arguments
// always make code in interrupt handlers fast and short
void AS3935_ISR()
{
  AS3935_ISR_Trig = 1;
}

It seems to be working (based on what I'm seeing using the serial monitor) and updating my controller (HomeSeer), although hard to know how well it's working without lightning in the area. I'll have to find a way to simulate lightning.

I have both the lightning sensor and the radio hooked up to the SPI bus.

Cheers
Al

EDIT: The diagram above is incorrect, I had to connect the lightning sensor breakout board to 5V, it did not seem to work at 3.3V in this configuration.

[hek]

Sweet. Would you want to create a pull request when you're ready with this example (including AS3935 library)?

[Sparkman]

@hek Thanks and yes, will do.

[Sparkman]

@hek The AS3935 Sensor also registers the energy intensity. What sensor type would be the best way to send that data to the controller? I'm using S_DISTANCE for the calculated distance, but would also like to capture the energy intensity. The energy intensity is returned as a 32 bit integer.

Also, the AS3935 returns the distance in km, but I believe S_DISTANCE is in cm. Is there a way to specify different units or should I have the sketch convert it to cm and then have the controller convert back to km?

Thanks
Al

[hek]

Oh.. than sensor is more advanced than I thought.

Send distance in "meter" for now. Stupid thing that the distance sensor example we're sending in cm in the first place.

Energy intensity is harder. What unit that is that? Maybe you could send it in VAR_1 for now?

[Sparkman]

@hek The sensor has a number of registers that can be set and/or read, so depending what someone wants to do with it, additional parameters may be sent.

Ok, will do regarding the units. The energy intensity is just a relative value with no units associated with it. I saw one sketch for a different breakout board for the same chip that converted the intensity to a value in the range of 1-10. The actual value returned can be as large as 16843008. I'll take a look at VAR_1, but don't believe the HomeSeer plugin supports that yet. As a test I used I used V_WATT/S_POWER for now.

Cheers
Al

[jeylites]

@Sparkman

If you can give me some time say around June or July, I'll be going to a tropical country with lots of lightning. I could test it out for you using Vera.

[Sparkman]

@jeylites Thanks, I appreciate the offer. July/August are prime thunderstorm season where I live and they are forecasting a possible thunderstorm for today, so I'm hoping to confirm that everything is working today :-)

Cheers
Al

[soward]

I put one of these together a short while ago -- just missed a storm rolling though, but another round might come through later. There's a reference in the code to AS3935_CAPACITANCE and a comment suggesting it be set to "THE NUMBER LISTED ON YOUR BOARD", however I'm seeing no number listed on the board. Am I just over looking it or is it something you derive?

thanx,
JpS

[Sparkman]

@soward So far the thunderstorms have skirted our area, but more to come tonight. Here's hoping ;-)

The Capacitance value is written on the bag the sensor came in. If you don't have the bag anymore, send an email to TechnicalSupport@PlayingWithFusion.com and they should be able to cross reference your order and provide the value. How does your sketch compare to mine?

Cheers
Al

[soward]

@Sparkman great thanx, I do have the bag somewhere in the pile-of-parts-bags. So far I have only used the demo sketch from playingwithfusion, but once it appears to detect something I'll probably use yours as a base and branch out form there. I'm using a Vera so I can try to use VAR_1 as hek suggested.

[hleidecker]

Also, the AS3935 returns the distance in km, but I believe S_DISTANCE is in cm. Is there a way to specify different units or should I have the sketch convert it to cm and then have the controller convert back to km?

The actual value returned can be as large as 16843008. I'll take a look at VAR_1, but don't believe the HomeSeer plugin supports that yet. As a test I used I used V_WATT/S_POWER for now.

Two mechanisms have been implemented in the HomeSeer controller plugin (1.0.5574.17274) to support custom unit strings in the controller UI:

• V_UNIT_PREFIX (only available in the development branch of the MySensors library). The prefix provided in the V_UNIT_PREFIX message will precede the default metric unit (defined by the plugin e.g. m (meter) for the distance sensor). The sensor configuration (metric/imperial) can be set by the user as a property on S_ARDUINO_NODE device via the HomeSeer UI. Please note, the prefix will not take effect when the sensor configuration is set to imperial.
• A user defined unit string. A unit string can be defined by the user. The metric/imperial configuration unit string and unit prefix will be ignored if a user defined unit string exists. The user defined unit string can be set by the user as a property on the device e..g. S_DISTANCE via the HomeSeer UI.

The HomeSeer MySensors plugin is available here.

Best regards,
Henrik

[Sparkman]

@hleidecker Thanks Henrik!

[Sparkman]

Hi all,

Well I was finally home when a thunderstorm rolled through and I was able to test the sensor and the sketch. Even though the sensor appeared to be working at 3.3V, I had to change it to 5V to get it to work properly with the USB powered Nano I have it connected to. I modified the sketch slightly (updated in my earlier post) to no longer send data when disturbers or unknown interrupt sources were detected. It's working great now and just need to put it into a case. I may use a different Arduino as well.

Cheers
Al

[Sparkman]

@hek said:

Sweet. Would you want to create a pull request when you're ready with this example (including AS3935 library)?

Hi Henrik,

Pull request submitted. Hopefully I did it correctly.

Cheers
Al

[hek]

Nice that you finally got some lightings to test your sketch.

Pull request looks all ok!

[Tore André Rosander]

Is it possible to detect the distance to the lightningstrike?
I was thinking to get some sort of detector to notify me if there is ligning registered X km away from my home.

[boozz]

@Tore-André-Rosander

You would need a sound detector for the thunder. Time (in milliseconds) between lightning and thunder times 0.34[m].

Same as you would do it with your own sensors (eyes and ears) :-)

BR,

Boozz

[Sparkman]

@Tore-André-Rosander Yes, the sensor can detect the distance. See the details of the sensor here: http://playingwithfusion.com/productview.php?pdid=22&catid=1001. Although I'm starting to believe that it's actually a lightning repeller rather than a lightning sensor as we've had very little lightning in our area after I installed it :laughing:

Cheers
Al

[alexsh1]

I found a similar sensor in the UK and added this to the list of my to be sensors for the weatherstation. Can I use it inside or it has to be placed outside to have a direct vision?

http://www.embeddedadventures.com/as3935_lightning_sensor_module_mod-1016.html