Simple circuit to convert a toggle switch turning on into a short pulse
Here's an easy way to do it using a 555:



and here's the LTspice circuit list if you want to run a simulation.

Version 4
SHEET 1 880 1140
WIRE -480 576 -624 576
WIRE -352 576 -480 576
WIRE 0 576 -352 576
WIRE -352 640 -352 576
WIRE -240 640 -352 640
WIRE -32 640 -176 640
WIRE -480 656 -480 576
WIRE -352 720 -352 640
WIRE -320 720 -352 720
WIRE -32 720 -32 640
WIRE -32 720 -96 720
WIRE -64 784 -96 784
WIRE -624 800 -624 576
WIRE -592 800 -624 800
WIRE -480 800 -480 736
WIRE -480 800 -528 800
WIRE -624 848 -624 800
WIRE -592 848 -624 848
WIRE -480 848 -480 800
WIRE -352 848 -480 848
WIRE -320 848 -352 848
WIRE 48 848 -96 848
WIRE -480 880 -480 848
WIRE -624 896 -624 848
WIRE 0 912 0 576
WIRE 0 912 -96 912
WIRE -352 976 -352 848
WIRE -64 976 -64 784
WIRE -64 976 -352 976
WIRE -624 1008 -624 976
WIRE -480 1008 -480 944
WIRE -480 1008 -624 1008
WIRE -32 1008 -32 720
WIRE -32 1008 -480 1008
WIRE -624 1072 -624 1008
FLAG -624 1072 0
FLAG 48 848 OUT
FLAG -592 848 +12
SYMBOL Misc\\NE555 -208 816 M0
SYMATTR InstName U2
SYMBOL voltage -624 880 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
WINDOW 3 24 104 Invisible 2
SYMATTR Value PULSE(0 12 1 .01)
SYMATTR InstName V1
SYMBOL cap -496 880 R0
SYMATTR InstName C1
SYMATTR Value 2µ
SYMBOL res -464 752 R180
WINDOW 0 -50 67 Left 2
WINDOW 3 -59 34 Left 2
SYMATTR InstName R4
SYMATTR Value 470k
SYMBOL diode -528 784 R90
WINDOW 0 -38 25 VBottom 2
WINDOW 3 -34 28 VTop 2
SYMATTR InstName D4
SYMATTR Value 1N4148
SYMBOL cap -176 624 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C2
SYMATTR Value 0.1µ
TEXT -600 1040 Left 2 !.tran 15