The example code for tuning the antenna of the LIGHTNING DETECTOR AS3935 does not seem to do anything.
I install the code and configure it for SPI and the monitor display is:
“AS3935 Franklin Lightning Dete actor”
“Lightning Detector ready to tune antenna!”
“16”
I have oscilloscope connected to the INT pin and it shows a steady 3.3 VDC.
Please explain??
Thanks
Hmm… I’m trying to recreate your issue, but using the default example code (in SPI), I’m seeing the following attached image. I’ll need some more info.
Possibly we are using different codes; I have found several errors in the latest code posted on GITHUB.
I tried again today and when I first power up the boards the INT is zero vdc; when I trigger a lightning input the INT output jumps to 3.3 and stays there.
Attached is the code I am using. Can you post the code you are using?
/*
This example sketch will walk you through how to tune the resonance frequency
of the antenna. Testing with a Saleae Logic 8 Pro, I've found that freshly
manufactured boards here at SparkFun will have a frequency around ~512Hz (2.4
percent deviation) by default. This falls well within the optimal value of 3.5 percent
suggested in the datasheet on page 35. However if you'd like to tune that
frequency, the chip provides internal capacitance that can be modified by the
library. You'll need a logic analyzer, oscillscope, or some method of reading
a 32kHz square wave (more on that below by division ratio function call) connected to the "INT" pin.
By: Elias Santistevan
SparkFun Electronics
Date: April, 2019
License: This code is public domain but you buy me a beer if you use this and we meet someday (Beerware license).
Hardware:
This is SparkFun's Qwiic Lightning Detector and so is compatible with the Qwiic
system. You can attach a Qwiic cable or solder to the I-squared-C pins.
You'll also need a wire attached to the interrupt.
5/10/2019 For SPI Solder jumper on bottom of board
5/16/2019 Modified for SPI
*/
#include <SPI.h>
#include <Wire.h>
#include "SparkFun_AS3935.h"
// 0x03 is default, but the address can also be 0x02, 0x01, or 0x00
// Adjust the address jumpers on the underside of the product.
#define AS3935_ADDR 0x03
#define ANTFREQ 3
// If you're using I-squared-C then keep the following line. Address is set to
// default.
//SparkFun_AS3935 lightning(AS3935_ADDR);
// If using SPI, uncomment the line below.
SparkFun_AS3935 lightning;
void setup()
{
Serial.begin(115200);
Serial.println("AS3935 Franklin Lightning Detector");
SPI.begin(); // For SPI
//Wire.begin(); // Begin Wire before lightning sensor.
//if( !lightning.begin() ){ // Initialize the sensor.
if( !lightning.beginSPI(9, 2000000) ) { //Uncomment for SPI
Serial.println ("Lightning Detector did not start up, freezing!");
while(1);
}
else
Serial.println("Lightning Detector ready to tune antenna!");
// When reading the frequency, keep in mind that the given frequency is
// divided by 16 by default. This can be changed to be divided by 32, 64, or
// 128 using the line below. So for example when reading the frequency on a
// fresh board, the frequency I'm reading is 32.05kHz; multiplied by 16 and
// the result is 512.8kHz. This is 2.56 percent away from the 500kHz ideal
// value and well within the 3.5 percent optimal tolerance. If I were to
// change the division ratio to 32, then I read a value of 16kHz.
//lightning.changeDivRatio(32);
// The following function call is just a sanity check. It will return a value
// of 16 by default but can be 32, 64, or 128, depending on what you change
// it too.
byte regVal = lightning.readDivisionRatio();
Serial.println(regVal);
// This will tell the IC to display the resonance frequncy as a digital
// signal on the interrupt pin. There are two other internal oscillators
// within the chip that can also be displayed on this line but is outside the
// scope of this example, see page 35 of the datsheet for more information.
lightning.displayOscillator(true, ANTFREQ);
// To stop displaying the frequncy on the interrupt line, give "false" as a
// parameter.
//lightning.displaying(false, ANTFREQ);
//Here you give a value of 0-16, which increases the capacitance on
//the RLC circuit in steps of 8pF, up to 120pF.
//The change in frequency is very modest. At 15 (max), I found that the
//frequency was sitting around 490kHz down from 512kHz. Consider that
//the equation for calculating frequency in an RLC circuit is:
// f = 1/(2pi*sqrt(LC)), just a mental morsel.
lightning.tuneCap(1);
Serial.println("Example3_Tune_Antenna_SPI_WJL");
}
void loop() {
}
I did find a semi-colon issue after the SPI.begin(); Otherwise, I’m using the default latest code from the repo, see below.
#include <SPI.h>
#include <Wire.h>
#include "SparkFun_AS3935.h"
// 0x03 is default, but the address can also be 0x02, 0x01, or 0x00
// Adjust the address jumpers on the underside of the product.
#define AS3935_ADDR 0x03
#define ANTFREQ 3
// If you're using I-squared-C then keep the following line. Address is set to
// default.
//SparkFun_AS3935 lightning(AS3935_ADDR);
// If using SPI, uncomment the line below.
SparkFun_AS3935 lightning;
void setup()
{
Serial.begin(115200);
Serial.println("AS3935 Franklin Lightning Detector");
SPI.begin(); // For SPI
// Wire.begin(); // Begin Wire before lightning sensor.
//if( !lightning.begin() ){ // Initialize the sensor.
if( !lightning.beginSPI(9, 2000000) ) { //Uncomment for SPI
Serial.println ("Lightning Detector did not start up, freezing!");
while(1);
}
else
Serial.println("Lightning Detector ready to tune antenna!");
// When reading the frequency, keep in mind that the given frequency is
// divided by 16 by default. This can be changed to be divided by 32, 64, or
// 128 using the line below. So for example when reading the frequency on a
// fresh board, the frequency I'm reading is 32.05kHz; multiplied by 16 and
// the result is 512.8kHz. This is 2.56 percent away from the 500kHz ideal
// value and well within the 3.5 percent optimal tolerance. If I were to
// change the division ratio to 32, then I read a value of 16kHz.
//lightning.changeDivRatio(32);
// The following function call is just a sanity check. It will return a value
// of 16 by default but can be 32, 64, or 128, depending on what you change
// it too.
byte regVal = lightning.readDivisionRatio();
Serial.println(regVal);
// This will tell the IC to display the resonance frequncy as a digital
// signal on the interrupt pin. There are two other internal oscillators
// within the chip that can also be displayed on this line but is outside the
// scope of this example, see page 35 of the datsheet for more information.
lightning.displayOscillator(true, ANTFREQ);
// To stop displaying the frequncy on the interrupt line, give "false" as a
// parameter.
//lightning.displaying(false, ANTFREQ);
//Here you give a value of 0-16, which increases the capacitance on
//the RLC circuit in steps of 8pF, up to 120pF.
//The change in frequency is very modest. At 15 (max), I found that the
//frequency was sitting around 490kHz down from 512kHz. Consider that
//the equation for calculating frequency in an RLC circuit is:
// f = 1/(2pi*sqrt(LC)), just a mental morsel.
lightning.tuneCap(1);
}
void loop() {
}
Unfortunately I’m not seeing what you’re seeing. I’m using the lightning detector hooked up to the SPI pins on an Arduino Redboard as follows:
CS → 9
MISO->12
MOSI->11
SCK->13
…and of course, the interrupt to my logic analyzer.
OK, MY error.
I was using pin #9 for CS; all the other examples in the library use PIN #10.
Might be a good idea to change the library so all the examples use the same pins.