ShetLand:
Very Heath Robinson, but cool.
Hahahaha. I had to Google Heath Robinson, but yes, that's just what I'm doing. Just without the strings and whirly-gig sorta things with a chin strap!
So far, I've found: VCNL4010 Proximity/Light sensor : ID 466 : $7.50 : Adafruit Industries, Unique & fun DIY electronics and kits short-range motion sensor,
https://www.ebay.com/itm/Tiny-Micro-Nano-Servo-3-7g-For-RC-Airplane-Helicopter-Drone-Boat-For-Arduino/192001529245?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 Micro servo
I'm getting there. I hope it doesn't look too getto. :