This simple circuit will enable you to visualize distant thunder lightning through a correspondingly choreographed LED flashes, exactly in accordance with the lightning that may be taking place somewhere in the distant sky, the response will be simultaneous and thus much prior to the sound that may reach your ears after a few seconds.
RF from Thunder Lightening
Thunder lightnings are basically like huge electric arcs, and thus generate a proportionate amounts of huge RF signals in the ether every time these flash in the sky.
The tiny RF detector circuit which was initially developed for catching cell phone RF waves, could be as effectively used for the proposed lightning detector design as well.
Parts List R1 = 2M2,R2 = 100K,R3 = 1K, C1 = 0.01uF, A1, A2 = IC 324
Referring to the above simple thunder lightning detector circuit, the configuration is basically a couple of opamps from the IC LM324 wired up as a high gain amplifier circuit.
The antenna could be a meter long flexible wire used here for receiving the RF disturbances from the thunder lightning arcs.
Since the circuit is a high gain amplifier, it could become easily upset and give wrong results if certain things are not taken care of.
All the interconnections must be as small as possible, and the PCB must be thoroughly cleaned with thinner in order to remove any sort of flux residue which could otherwise create malfunctioning of the circuit.
How to Test the Setup
After constructing the above design, initially do not connect any wire to the antenna terminals.
Make sure the LED stays shut off after the circuit is powered, and use a 9V PP3 battery for powering the circuit, an AC/DC adapter will not work as you will see the LED always ON if a mains adapter is used.
Next, take a gas lighter and click the device with its tip held close to the antenna point of the circuit.
You should find the LED illuminating and flashing in response to every clicking of the gas lighter.
This would confirm a correctly built detector circuit.
Connecting the Antenna
Finally, you can attach the 1 meter long antenna wire to the shown position and wait for a possible thunder lightning strikes in the vicinity.
You will be surprised to see the LED dance and flash exactly in tandem with the lightning illumination sequences.
You could amplify the Led response by adding an opto coupler and a corresponding high watt lamp with the circuit, such that the whole room gets dazzled each time the lightning flashes in the sky.
Please note that in order to ensure 100% working of this circuit, you will have to use a battery as the DC supply for the circuit. And connect the negative line of the circuit with some kind of earthing line. In my case I connected it with my bathroom tap.
Wait...I don't quite remember whether the earthing is required or not if a battery is used. May be I had used an adapter as the supply and therefore I had to use the external earthing for suppressing the 50Hz disturbance....please confirm this at your end!
And make sure the antenna wire is very long. In my experiment I used a 2 to 3 meter long flexible wire.
For testing you can try clicking your gas lighter near the antenna, the LED must respond with corresponding blinking.
I happened to discover this unique property of this circuit as a thunder lightning detector accidentally, while testing for mobile RF detection. Thankfully it was rainy season then, otherwise I could have never come across this outstanding feature of this circuit.
Using 10 LED Display
In this design you can visualize and assess the strength of an approaching thunder storm and lightening, through a 10 LED bar graph display.
The up/down movement of the LED on the bar graph will provide a direct indication of how strong or how near the thunder storm may be.
The entire circuit diagram of the 10 LED based thunder storm lightening detector can be seen in the following diagram.
It is basically a 10 LED LM3915 driver circuit integrated with a AM radio.
Alternatively, the circuit has a small speaker which can be held close to the speaker of the radio.
An AM radio being a very sensitive thunder lightening detector will detect an approaching thunder storm and reproduce the sound of the thundering on its speaker. This sound from the radio speaker will hit the LM3915 speaker and convert the results into an incrementing LED illumination on the bar graph providing a direct display of how strong the distant thunder lightening may be.
Lightning VLF and HF Monitor Circuit
It is well known that lightning strikes which hit the ground instead of clouds produce significantly higher VLF (Very ow Frequency) emissions. The ratio of cloud-to-ground or cloud-to-cloud discharge, hits per flash, leader steps, amplitude, and relative range may all be determined by observing both VLF and HF (High Frequency).
This straightforward receiver can keep an eye on both HF and VLF signals. The device could let you to remain indoors during a thunderstorm and shield you from the downpour and 100 kilojoule discharges.
How to Make the Antenna Coil L1
The antenna coil L1 may be constructed to detect and monitor VLF by winding 94 rounds of 33-gauge magnet wire around an 11-inch cardboard disc. To monitor HF from lightning strikes, the antenna coil (L1) could be a standard RF choke.
Alternatively, L1 could be constructed using around 100 turns of extremely tiny magnet wire on a 1/2-inch-long ferrite core (or any equivalent spare choke would suffice).
The antenna could be any 6-inch flexible wire.
How the Circuit Works
The first TL071 FET operational amplifier is set up as a preamp. A second TL071 boosts the gain of the lightning detection. You can attach high-impedance headphones or an oscilloscope to test-point#1. After rectifying, the diode/resistor/capacitor components modify the output for quick attack/slow decay.
The second test point #2 is for connecting to chart recorders or event counters.
The circuit's outputs are connected to low-voltage piezo buzzers BZ1 and LM3914 bargraph display drivers IC3.
IC3 outputs illuminate the LED bargraph sequentially in response to lightning detection. Dual 9V supplies are used to power the circuit.
How to test
Make use of the two separate coils for L1 and power the circuit during the tests. For the HF coil on L1, a decent broadband source of noise, for example a light dimmer, should be detectable on the LED graph.
When VLF coil is used for L1, switching a far away incandescent light on and off repeatedly should allow the LEDs to run sequentially in response to the VLF.