Version 4
SHEET 1 1144 1448
WIRE -2720 16 -3136 16
WIRE -2544 16 -2720 16
WIRE -3136 80 -3136 16
WIRE -2720 112 -2720 16
WIRE -2544 112 -2544 16
WIRE -3344 192 -3424 192
WIRE -3136 192 -3136 144
WIRE -3136 192 -3344 192
WIRE -2544 224 -2544 192
WIRE -3344 288 -3344 272
WIRE -3344 288 -3424 288
WIRE -2928 288 -3344 288
WIRE -2720 320 -2720 192
WIRE -2240 320 -2720 320
WIRE -2928 352 -2928 288
WIRE -2832 352 -2928 352
WIRE -2928 400 -2928 352
WIRE -2720 400 -2720 320
WIRE -2832 448 -2832 352
WIRE -2832 448 -2864 448
WIRE -2784 448 -2832 448
WIRE -2928 768 -2928 496
WIRE -2720 768 -2720 496
FLAG -2544 224 0
FLAG -2720 768 0
FLAG -2928 768 0
FLAG -3600 592 0
FLAG -3600 512 Vresistor
SYMBOL voltage -2544 96 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V2
SYMATTR Value 2.4
SYMBOL npn -2784 400 R0
SYMATTR InstName Q2
SYMATTR Value 2N3904
SYMBOL res -2736 96 R0
SYMATTR InstName R1
SYMATTR Value 220K
SYMBOL npn -2864 400 M0
SYMATTR InstName Q3
SYMATTR Value 2N3904
SYMBOL diode -3152 80 R0
SYMATTR InstName D1
SYMATTR Value 1N4148
SYMBOL voltage -3600 496 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value PULSE(1Meg 250 0 0 0 0.03 1 10)
SYMBOL res -3360 176 R0
SYMATTR InstName R2
SYMATTR Value R=V(Vresistor)
TEXT -3120 -232 Left 2 !.tran 0 10 0 50u
TEXT -3008 96 Left 2 ;David Pilling 2015
TEXT -2480 368 Left 2 ;Output to Arduino Analogue 1 pin
TEXT -3640 240 Left 2 ;Power to clock