AS3935-DK

AS3935 Franklin Lightning Sensor and Lightning Emulator Application Note AS3935 Franklin Lightning Sensor www.austriamicrosystems.com www.austriamicrosystems.com Revision 1.00 1 - 16 AS3935 Franklin Lightning Sensor and Lightning Emulator Table of Content Features .................................................................................................................................................................. 2 Franklin Lightning Sensor Description..................................................................................................................... 3 Lightning Emulator .................................................................................................................................................. 5 How to get started with Franklin Lightning Sensor demo kit .................................................................................... 6 GUI Description ....................................................................................................................................................... 6 History Description .................................................................................................................................................. 8 Layer Stack of Lightning Sensor ............................................................................................................................. 9 Layout Recommendations ...................................................................................................................................... 9 Layout of Lightning Sensor ................................................................................................................................... 10 Bill of Material of Lightning Sensor ........................................................................................................................ 12 Layout of Lightning Emulator ................................................................................................................................ 13 Bill of Material of Lightning Emulator ..................................................................................................................... 15 Copyright ............................................................................................................................................................... 16 Disclaimer ............................................................................................................................................................. 16 Contact Information ............................................................................................................................................... 16 Features







Fully operational Lightning Sensor Supplied by a 3V CR2032 battery with long battery life time >1000 hours Buzzer alarm for early warning of storm 128x32 display with blue backlight for detail information about storm warning Automatic antenna and RCO’s tuning implemented USB connection for adjusting AS3935 detail settings Handheld Lightning Emulator Emulation of Lightning with different distance (far, close, closest) and Noise generation Programmable Lightning Sensor AS3935 Key features








Lightning Sensor warns of lightning storm activity within a radius of 40km Distance estimation to the head of the storm down to 1km Detects both cloud-to-ground and intra-cloud (cloud-to-cloud) flashes Embedded man-made disturber rejection algorithm Programmable detection levels enable threshold setting for optimal controls SPI and I²C interface is used for control and register reading Antenna Tuning to compensate variations of the external components Supply voltage range 2.4V to 5.5V Power-down, listening, and active mode www.austriamicrosystems.com Revision 1.00 2 - 16 AS3935 Franklin Lightning Sensor and Lightning Emulator Franklin Lightning Sensor Description Board Description Figure 1: Lightning Sensor, Top Figure 2: Lightning Sensor, Bottom Component Description Top Label Name Info A ON/OFF B BUTTON C D E F G H I IDD BUZZER LCD 500kHz Antenna AS3935 MCU AS3935 Interface Power on/off the Demoboard. Short Press: The actual time of the RTC is shown. Long Press (>1s): The statistics of the AS3935 is cleared IDD Jumper for current measurement of AS3935 Audio Information for Lightning and Disturber 128x32 Display, blue backlight 100uH LF Antenna for AS3935 Lightning Sensor Microcontroller PIC24FJ64GB002 SPI Interface to AS3935 Component Description Bottom Label Name Info J K L USB – Connector USB Interface for the GUI Power Management; Analog Switch AS1362, AS1746 CR2032 BATTERY Insert CR2032 in here Buzzer Label D Modulation Info 1x 500ms ON Lightning detected 2x 150ms ON 4x 50ms ON Lightning detected: Distance to the previous lightning has changed Disturber was detected Note: The buzzer alarm can be modified or turned off via the GUI. www.austriamicrosystems.com Revision 1.00 3 - 16 AS3935 Franklin Lightning Sensor and Lightning Emulator LCD Label Description Booting After power on the demo board, the austriamicrosystems logo and the firmware version will be displayed. Sign Antenna Tuning After the startup the antenna of the AS3935 is automatically tuned. The tuning uses the internal array of capacitors to achieve 500kHz as resonance frequency. The resonance frequency and the internal capacitance are shown on the LCD. RCOs Calibration After the antenna tuning the internal RC-Oscillators are calibrated. The SRCO is calibrated to 32kHz and the TRCO is calibrated to 1.1MHz. Both frequencies are displayed. USB connected The demo board can be connected via USB. As soon as the USB bus is connected the sensor is turned off and all settings of the AS3935 can be saved in the GUI. If the demo board is power cycled when the USB plug is already connected, the LCO and RCO calibration is not executed, in order to allow the user to do those calibrations via the GUI. Listening Mode After the calibration, the Lightning sensor is set in listening mode. No storm is within detection range. Lightning Lightning has been detected. The distance estimation and movement of the head of the storm is shown afterwards. The distance to the head of the storm gets closer. This symbol indicates a lightning – the text give further information. The distance to the head of the storm gets farther. Noise Floor Detected Continuous noise is jamming the AS3935 AFE; during this time the sensor cannot detect the presence of lightning activities. Disturber Detected Disturbers have been received by the AS3935 and rejected by the disturber rejection embedded algorithm. Real Time Clock (RTC) The demoboard has a built in RTC that must be synchronized with a PC. Once the RTC is set to the current time, it is possible to monitor lightning over time. Note: The RTC is reset to midnight of 1. January 2012 and the history is cleared when the demo board is switched off and on again. www.austriamicrosystems.com Revision 1.00 4 - 16 AS3935 Franklin Lightning Sensor and Lightning Emulator Lightning Emulator Board Description J A F B G H C D E Figure 3: Lightning Emulator Description Top Lightning Emulator Description Label Name Description A Disturber B Noise C D E Far Strike Mid Strike Close Strike F Antenna G On/Off Switch H Battery holder CR2016 Emulates a disturber on the antenna; red LED is flashing up Emulates noise on the antenna; red LED keeps flashing until noise disappears again (3s) Emulates a pattern of a lightning with far distance Emulates a pattern of a lightning with closer distance Emulates a pattern of a lightning with the closest distance The different patterns are modulated on the 500kHz carrier that is transmitted via the LF antenna. Turn both switches to ON to supply the lightning emulator; As soon as the demo board is switched on, the ON LED flashes up once a second to indicate being turned on. Supply the emulator with 3 stacked CR2016 batteries to generate 9V. Label Name Info G A B ON Disturber Noise J Strike Blue led flashes up once a second Flash up red if disturber is emulated Flash up for 3s, as long as noise is emulated Flash up yellow if far strike is emulated Flash up orange if mid strike is emulated Flash up red if close strike is emulated LEDs www.austriamicrosystems.com Revision 1.00 5 - 16 AS3935 Franklin Lightning Sensor and Lightning Emulator How to get started with Franklin Lightning Sensor demo kit • Insert the 3V battery (CR2032) in the battery holder “C” on the AS3935 demo board. • Insert a 3V battery in the battery holder “G” on the Lightning Emulator. • Position the lightning emulator and the AS3935 demo board in such a way that both antennas are in parallel to each other. Keep a distance of 10-15 cm between both boards. • Turn on the AS3935 Lightning Sensor via the ON/OFF – switch “A”. When you switch on the board you will see on the LCD the austriamicrosystems logo followed by the LCO and the RCO calibration. After successful calibration the AS3935 goes into sense mode awaiting a lightning. Note: The LCO should be tuned to 500 kHz, the TRCO to 1.1 MHz and the SRCO to 32 kHz. If this procedure wants to be done manually, connect the USB plug before power ON the demo board via switch “A”. • Turn on the Lightning Emulator via the ON/OFF – switch “F”. When turned on, the green LED will be continuously on. Note: Make sure the battery of the Lightning Emulator is full. Otherwise lightning might not be recognized correctly. • Now you can start to press the switches, farther strike, close strike and closer strike (button “B, C, D”) on the Emulator, simulating a lightning which will be detected by the sensor. The display will flash up showing the signs described above and the buzzer will trigger an alarm. If noise is emulated (button “A”) the AS3935 demo board will show “Disturber detected”. GUI Description • • Install the GUI and start the software. As soon as the demo board is connected the USB and AS3935 Symbol in the corner becomes green. The LCD will show the USB connection and the sensor is turned off. Figure 4: GUI of the AS3935 Lightning Sensor www.austriamicrosystems.com Revision 1.00 6 - 16 AS3935 Franklin Lightning Sensor and Lightning Emulator The following parameters can be defined on the AS3935 Lightning Sensor:
Power Down In Power down Mode (R0=1), the entire AS3935 is switched off. The typical current consumption is 800nA. After Power up again, the TRCO is not calibrated, that must be done by the user pressing the button “Calibrate RCOs” and respectively “Calibrate LCO” if needed.
LNA Settings The LNA settings have to be changed according to the location of the lightning sensor (outdoor vs. indoor) as described in the AS3935 datasheet.
Noise Floor: The threshold for the trigger of the noise floor interrupt can be selected via this drop down menu.
Disturber: If the Disturbers are masked, no interrupts will occur if a disturber is detected.
Disturber Rejection Setting: With the watchdog threshold level WDTH (R1) it is possible to increase the robustness to disturbers. The AS3935 is capable of rejecting impulse signals, like spikes, picked up by the antenna. This spike rejection can be improved via this SREJ Level defined in R2. By default, R2 = 0x2. Larger values of SREJ correspond to more robust spike rejection.
Minimum Number of Strikes: It is possible to allow the AS3935 to issue lightning interrupts only if a minimum number of lightning have been detected in the last 15 minutes. This field allows setting it to 1, 5, 9 or 16 minimum numbers of lightnings.
Oscillators: If the AS3935 demo board is connected via USB to the GUI before power on the demo board, the oscillators are not calibrated. This can then be done manually via the GUI. First step is to measure the default resonance frequency of the oscillators by pressing “Measure”. The oscillators will show inaccurate values. Pressing “Calibrate LCO” will tune the antenna to 500 kHz, which will allow the user to calibrate also the RCOs by pressing “Calibrate RCOs”. The added tuning caps will be shown below. See the tuning sequence below: Measure default values Calibrate LCO Calibrate RCOs
Buzzer Control: The buzzer alarm can be modified for lightning only or can be completely turned off. The buzzer settings can be saved.
Save Settings / Restore Default Settings: All settings of the AS3935 and the buzzer can be saved by pressing “Save Settings”. To reset the values to the factory settings press “Restore Default Settings”.
Firmware Update: In order to update the firmware, open Help/Firmware Update (Ctrl+F) and select the new firmware revision.
Show History: The history of the occurred strikes can be read out via the GUI and saved to a log file.
Register Map: The entire register map can be readout via View/Register Map (Ctrl+M) and can be modified. www.austriamicrosystems.com Revision 1.00 7 - 16 AS3935 Franklin Lightning Sensor and Lightning Emulator Figure 6: Register Map History Description The demo board offers a volatile history that can be read out and its data can be saved into a log file. The history works as following:
It is possible to synchronize the RTC of the board with the time of your PC pressing “Sync RTC and Delete History”. The existing history in the memory is automatically deleted. A short pressing of the button "B" on the Lightning Sensor demo board shows the actual time on the LCD display.
Note: Right after every power up of the board the RTC is set to midnight of 1.January 2012, turning off the board the history will be deleted.
Each event detected by the Lightning Sensor is saved into the memory. It is possible to read out the history connecting the GUI and press the button “Read History”. The graph shows the estimated distance to the head of the storm over the time. www.austriamicrosystems.com Revision 1.00 8 - 16 AS3935 Franklin Lightning Sensor and Lightning Emulator
Zoom into the history by holding your left mouse button pressed.
Zoom out of the history by pressing the right mouse button.
Select some strikes in the graph and the details will be highlighted in the table below.
All data can be exported into a log file by pressing “Export History”.
It is possible to save maximum 190 lightning events in the memory. If the memory is full it will be displayed on the LCD to read out and delete the history. Please apply then “Read History”, “Export History” and “Sync RTC and Delete History”. Layer Stack of Lightning Sensor




PCB Material: FR4 1mm for Active Tag. FR4 1.6mm for Basestation 2 layer board Solder surface: chemical - tin Width of copper: 35µm Silk screen top/bottom: white Layout Recommendations



Do not cross the SPI lines with the sensitive inputs of the antenna. Below the 500 kHz LF antenna there should not be a GND plane. Make sure that the GND plane is routed carefully. Do not run SPI or any other interface on 500 kHz clock speed, in order to avoid cross-coupling. www.austriamicrosystems.com Revision 1.00 9 - 16 AS3935 Franklin Lightning Sensor and Lightning Emulator Layout of Lightning Sensor Board schematics www.austriamicrosystems.com Revision 1.00 10 - 16 AS3935 Franklin Lightning Sensor and Lightning Emulator Board Layout Figure 7: Top Layer Figure 8: Bottom Layer www.austriamicrosystems.com Revision 1.00 11 - 16 AS3935 Franklin Lightning Sensor and Lightning Emulator Bill of Material of Lightning Sensor www.austriamicrosystems.com Revision 1.00 12 - 16 AS3935 Franklin Lightning Sensor and Lightning Emulator Layout of Lightning Emulator Board schematics www.austriamicrosystems.com Revision 1.00 13 - 16 AS3935 Franklin Lightning Sensor and Lightning Emulator Board Layout Figure 9: Top Layer of Lightning Emulator Figure 10: Bottom Layer of Lightning Emulator www.austriamicrosystems.com Revision 1.00 14 - 16 AS3935 Franklin Lightning Sensor and Lightning Emulator Bill of Material of Lightning Emulator www.austriamicrosystems.com Revision 1.00 15 - 16 AS3935 Franklin Lightning Sensor and Lightning Emulator Copyright Copyright © 1997-2012, austriamicrosystems AG, Tobelbaderstraße 30, 8141 Unterpremstätten - Graz, Austria Europe. Trademarks Registered ®. All rights reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. All products and companies mentioned are trademarks or registered trademarks of their respective companies. Disclaimer Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification provisions appearing in its Term of Sale. austriamicrosystems AG makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement. Austriamicrosystems AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior to designing this product into a system, it is necessary to check with austriamicrosystems AG for current information. This product is intended for use in normal commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or life-sustaining equipment are specifically not recommended without additional processing by austriamicrosystems AG for each application. For shipments of less than 100 parts the manufacturing flow might show deviations from the standard production flow, such as test flow or test location. The information furnished here by austriamicrosystems AG is believed to be correct and accurate. However, austriamicrosystems AG shall not be liable to recipient or any third party for any damages, including but not limited to personal injury, property damage, loss of profits, loss of use, interruption of business or indirect, special, incidental or consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical data herein. No obligation or liability to recipient or any third party shall arise or flow out of austriamicrosystems AG rendering of technical or other services. Contact Information Headquarters austriamicrosystems AG Tobelbaderstraße 30 A-8141 Unterpremstätten - Graz, Austria T. +43 (0) 3136 500 0 F. +43 (0) 3136 5692 For Sales Offices, Distributors and Representatives, please visit: http://www.austriamicrosystems.com/contact www.austriamicrosystems.com Revision 1.00 16 - 16