Voila! Graphite Based Radio Detector

So in this video, i'm about to use graphite fillings for my Coherer Thunderstorm Warning Device. As we know, Coherer Receiver is using iron fillings to detect Electromagnetic Waves, but i do some experiment that using graphite from my AA battery, file it off as fine as i can. And after testing it works, it can detect Sparks, but the sensitivity may reduced a bit, but it still can be used as a thunderstorm warning device.