AS3935 Franklin Lightning Sensor IC

EDC · Joined: 26 Mar 2014 Posts: 971

Hello.
This sensor can detect "storm" from 40km
It detect lighting but can reject incorrect signals.

Sensor have antenna that must be tuned for 500kHz.
For that purpose device have internall capacitors that can be attached via software settings.
Device can be set to mode in which one pin give output of antena resonation/16 (this divider can be also set but this is default)
So we need some time base (1s from RTC or Timer) and once choose best tune value.
After best value is found there is no need to search it every boot.
Enough is to read it from eeprom and write to device reg.

But at every reboot, and after write correct tune value, RCO calibration is needed (takes 2ms)

If you find bug please share Very Happy

O-Family · Joined: 23 May 2010 Posts: 320 Location: Japan

Hi EDC
I also like this sensor.
What kind of system are you assembling?

I made it possible to operate about half a year on dry batteries.

The distance of lightning is also displayed on the LCD with an easy graph.

I can output the recorded lightning movement to the serial terminal.

I'm sorry it's written in Japanese.
http://www.ne.jp/asahi/shared/o-family/ElecRoom/AVRMCOM/AS3935/AS3935_test.html#AS3935Clk

EDC · Joined: 26 Mar 2014 Posts: 971

Haha

I know your code O-Family and thats why I mentioned about RTC for 1s signal Razz

For those who wants your code is not complicated but this is code for complete clock with alarms etc.
So essential way to understand how it works is blurred Very Happy

Thats why I read datasheet and want to clarify how to handle it- it is simple I think Very Happy

O-Family · Joined: 23 May 2010 Posts: 320 Location: Japan

Thank you for knowing my site!

My program is completed as a clock, but each process is divided into blocks.
If can understand Japanese comments, I think that it can be used as a module.
I am not good at English, so I'm sorry I have not written comments in English.

I think that your program is also good, but I was interested in your whole system!

albertsm · Joined: 09 Apr 2004 Posts: 5921 Location: Holland

amazing chip. had no idea something like that was possible and/or existed.
Thanks for sharing the code and pdf.

aphawk · Joined: 23 Jan 2010 Posts: 168 Location: Brazil

Hi EDC,

I have some problems with your program and my sensor.

First, in the sub tune_rco() :

This don't worked ( don't set the frequency to the correct ) :

EDC · Joined: 26 Mar 2014 Posts: 971

I isolate this routines from another project and some of them I write for this demo again.
Read address in I2C is bigger then address for writing Very Happy

I dont know how this happend but in code popup "Als_addr -1" Embarassed

So with this everything should work fine. Sorry for that Very Happy

I also try to fix this in first post.

aphawk · Joined: 23 Jan 2010 Posts: 168 Location: Brazil

EDC,

What a hell ..... I downloaded the last version from the datasheet in the AMS Website, Version 1.04... see this :

Maybe the AMS people likes to see many of us in despair kkkkk ! Wait for the next revision, they will put bit 7 here Laughing

!

Anyway, this information is in the case of the CI be set in powerdown mode, that is not the case here ( well ... i think .... is debatable, really Very Happy

).

But I used antena.7 , and this fixed the LCO frequency. But the only way I found to calibrate the SRCO and TRCO was using that auto-calibrate command sequence after made the antenna LCO tuning.

I had lost two days to learn a lot of this sensor, tried many ways to calibrate all the oscillators, and the best I could was put the Antenna oscillator in 500.680 hz. But the SRCO is at 1.134 Mhz , and the TRCO is running at 32468 Hz. My room temperature is 25 Celsius.

The datasheet indicate that is possible to make the manual calibration for SRCO and TRCO, but I can't made this work...

My sensor is a little deaf, even at maximum sensibility only detects a strike very near.
I buy another today, maybe I have a better luck.

Paulo

O-Family · Joined: 23 May 2010 Posts: 320 Location: Japan

Antenna tuning DISP_LCO is bit 7 of register 08h.
In my case, SRCO and TRCO are operating normally with automatic calibration.

The manual states that it is necessary to perform the CALIB_RCO command (Write 96h to register 3Dh) when putting AS3935 into power down mode.
In case of normal power on (including reset), I think that RCO automatic calibration (bit 6 of register 08h) is good after antenna tuning.

aphawk · Joined: 23 Jan 2010 Posts: 168 Location: Brazil

O-Family,

Thanks a lot for your confirmation.

I found one small bug in the EDC code, and that was blinding my sensor.

If the sensor catches some disturb or high noise , the interrupt goes high. If there is a lot of noise, this can happens very quickly.

After the instruction CALL Tune_rco() , there is a delay before the interrupt be enabled, about 500 milliseconds.
If during this time the interrupt fires, the INT pin goes HIGH, and stay HIGH, waiting for the interrupt register be read, and only after this the interrupt can works again.

But the interrupt enabled in Atmega is a Changing Level interrupt. If the pin stay high, interrupt never will be triggered and the Read_als flag was not set !

And even if other interrupt fire INSIDE the Do : Loop code, this will blind the sensor again.

Then I modified the code, disabling the interrupt, and checking if the Interrupt pin are in High state, then the code can proceed to check what was reported by the sensor. This resolved the blinding situation.

After that, I had a lot of beeps, like a Geiger counter kkkkk .... and can make a better adjust of noise level and watchdog. I had 2 or 3 beeps every minute, reported as Disturbs, and now I set the flag to ignore the Disturb detection with this small code :

O-Family · Joined: 23 May 2010 Posts: 320 Location: Japan

Hi aphawk

I am using the sensitivity setting of the sensor as the initial value.
It is an "indoor" mode.

EDC · Joined: 26 Mar 2014 Posts: 971

O-Family · Joined: 23 May 2010 Posts: 320 Location: Japan

Hi EDC

aphawk · Joined: 23 Jan 2010 Posts: 168 Location: Brazil

EDC,

Wow .... I think that maybe we can exchange our homes kkkkk ... at now, 21:08 , temperature outside my room is 29 Celsius, and is "so low" because some hours ago a storm with many rain passed here in São Paulo, Brasil...... really here is very hot ( and wet ) at this month.

I loved to see your picture, is like a dream to me. Snow, animals, quiet, all things I hoped ! What is the name of the city you live ?

Finally my sensor detected many strikes today ! From 27 Km ( the far ) until Storm Here, I'm happy with it.

My final goal is using this sensor with an ESP8266 with battery, this way I can put it at high, outside, some meters above my roof, sending only strikes report via WIFI using the website ThingSpeak. Will use the interrupt to wake up the ESP8266. But this is for some time ahead. I need to learn mode about ESP8266Basic to use sleep modes.

Now I will make small mods in this program, including one button to show the events in sequence with relative time between them.

I made one smalll routine to show the values of the SRCO and TRCO, will include then in the program.

Thanks for your permission to modify and share this project !

O-Family,

I see your project too, I learned a lot seeing your code. Thanks for sharing it !

I will make other project, and using one RTC, using the AVR sleep mode too, and awake with interrupt from sensor or pressing a button. Will use one small Nokia display too, but from now I will play a little more based in my Arduino Uno.

Paulo

O-Family · Joined: 23 May 2010 Posts: 320 Location: Japan