Finally found the right search terms to find another childhood book series I only half remembered. Turns out it was “Danny Dunn“. I could really only remember two stories’ plots, and that only pieces. One was a robot dragonfly, and the other was a cold ray that they used to cause rain, IIRC. I was about ready to spend an askme, but for once, there really was a previous question that applied to my current question, and the answer was revealed.
happy happy, joy joy