Its called Slappy Tank. And its awesome, I have been working on it with AI for about 4 months. Mostly collecting audio data from burning off different tanks of propane. You slap the side of the tank and record the audio with your phone, it then tells you how much propane is left in there. The tank needs to be calibrated to be accurate, which means slapping it at full or empty and ideally both to be within a few percent accuracy. Once you calibrate your tank once it never needs to be recalibrated unless you physically switch to a different tank. You can use it on 20 and 30lb propane tanks, the 30lb data isn't as accurate as the 20lb yet but will be dialed in the next update. It just launched yesterday! so well see how she goes. https://play.google.com/store/apps/details?id=ca.heronbone.slappytank&pcampaignid=web_share   submitted by   /u/Old-Box-5075 [link]   [comments]