Those little "Off" brand mosquito repellants with fan and belt hook:

[morningglory]

I bought one with the thought of hooking it on to my grandson's belt. The warnings on the package were terrifying. I set it up and hooked it on my belt so I could sit out and watch butterflies after doing a bit of gardening. Reading the package and looking it over for the first time, it looks like there is a tiny green vial of "repellant" in the thing. Looks like you could scrunch those Mosquito-repellant geranium leaves and put a leaf into the thing instead of the poison that they sell. The plants don't seem to repel mosquitoes, but if you rub the leaves they repel until you sweat. gonna try it as soon as I run out of the expensive "refill".