I'm experimenting with an open flame as an ion source for a no-moving-parts field mill. It also occurs to me that an open flame on the end of a lightning rod (ignited only when a storm approaches to save fuel) might make an interesting lightning shield/attractor. The tremendous number of ions would help to bring the local area closer to the cloud potential, discouraging strikes. When a strike does happen, it might be more inclined to follow the ion trail safely down to the lightning rod. It's pretty easy to design a gas torch that will burn in pouring rain, too. I don't think I'll be doing experiments, however!
Recent experiments have shown me that it is a lot easier to make a radiation detector similar to a Geiger counter using a PIN photodiode than I thought. The pulses from individual strikes are easily seen with a simple high impedance amplifier and the height is proportional to the energy of the particle making identification of the isotope possible.
A two-chamber ion chamber might be interesting to try. Air would be drawn into the first chamber where any free ions would be swept out. The air would then enter the second chamber, free of ions, and any decaying radon gas should be detectable. I wonder if the gamma background would dominate.
How about a chopped ion chamber? The polarity of the voltage on the outer can would be switched every couple of minutes and the resulting average currents would be held on two capacitors. The difference voltage would be proportional to the radiation flux without any zero problem. Maybe there should be a dead time right after the switch to let the chamber restablize.
Some of my projects have appeared in other places without attribution, including a book, making it look like I have copied them. I added a couple of notices to my pages and I am in the process of upgrading the projects to set them apart. First was the old rain detector. Then the deer repellent/ seismic sensor and electrostatics tutorial.
Other Back-Burner Ideas
How sensitive can "Franklin's Bells" be? Maybe a horizontal pendulum for the clapper and flat plates for the "bells". Maybe a beam-break detector for the output.
More complete, kit-like versions of some of the favorites.
Publish efficient voltage converter for LEDs.
Publish simpler DC lamp dimmers.
I have a few simple tube radio projects that might make an interesting read.
Beeper Probe changes pitch with voltage and frequency when RF is present. Indispensable!
pH meter
Push-pull version of the One-Transistor Reflex receiver using two transistors amplifies the RF differentially and the audio in parallel. Nice symmetry but I'm not sure if it is worth the trouble!
Transformer version for crystal earphone using some transformers I now have in great quantity. They are perfect for crystal earphones.
JFET or MOSFET one-transistor radio. (Works pretty well)
Improve All-Band receiver for more volume in crystal earphone
LED floating voltage source. (nifty)