For Bee Farmers, you can use audio and temperature sensing of Hive with acoustic Fourier Analysis to detect rise in wing flap rate when Worker Bees detect that the hive needs cooling but also rise in flap rate when a new Queen is born, so that farmers can start a new Hive by transporting new Queen. Low cost telemetry and processing ( comparing dominant frequency of sound with temperature changes to help Bee Farmers manage each Hive for more timely maintenance to avoid loss of Queen Bee and increase population and prodction of honey. Audacity can be used for overnight research analysis and then implemented by DSP with uC and Wifi (ARM solutions) for final product.
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Next idea.
Many graduates are learning the value of sensing sub nanosecond impulse of Partial Discharge in transformers. PD Sensing and swept frequency analysis of large $M transformers and switch gear in power distribution stations is common practise. Also, There are many lower cost handheld solutions using impulse RF, UV, radiated and conducted detection of Partial Discharge. But still too expensive and ignorance prevails.
Google Scholar indicates rapid rise in grad theses on this PD topic over last decade and is well understood in industry for dry transformers but often overlooked in contaminated oil filled transformers that prohibit cost of such monitoring solutions on a $5k-$50k DT transformers. So there is a need or high volume low cost $100 data collection sensing of PD impulse event monitors and historical preventive maintenance feedback when to test for H2 gassing or even purify oil when H2 concentration levels in oil exceed 5%. (Category 3 alert to remove unit before rising risk of explosion). RF antenna may be internal or external or monitor ground spikes from tank. But CT's cost more than $100, when all you need is 1 turn around ground strap. Bonus for fault location isolation sensing by impulse triangulation is more complex with transformer models by radiated and conducted arcs. PD repetition rates start around 1ppm(pulse per minute) and increase to 1 or 2 pulse per cycle, sometimes with saturated magnetization currents from remnance but usually with contamination or voids in insulation measured in parts per million (ppm)
Rising H2 gassing in oil filled transformers can be a common in India, Europe, even Canada, in sealed tanks. Explosions may be infrequent but are nasty if PD or DGA on oil is ignored. (oil sample gas analysis)
Very low cost wireless PD history monitor like AMR industry for monitoring power meter network except for maintenance. PD measurement concept is over 50yrs old and I expect the phenom was observed by Tesla, Siemens, Coulomb and Faraday even if not fully understood. Still today more characteristics need to be understood.
ANother recent paper from experts at U of S on PD.