* SPICE netlist
Q3 N010 N013 0 0 2SCR554P
Q4 N012 N014 0 0 2SCR554P
Rmotor N011 N010 1
Lmotor N012 N011 .05
V1 N003 0 5 volt
Q2 N012 N001 N003 0 2SAR554P
Q1 N010 N002 N003 0 2SAR554P
R1 N018 N014 33
R2 N017 N013 33
R3 N006 N002 33
R4 N007 N001 33
D1 0 N010 D
D2 0 N012 D
D3 N010 N003 D
D4 N012 N003 D
Q1_driver N006 N008 0 0 BC547B
Q2_driver N007 N009 0 0 BC547B
Q3_driver N017 N019 N021 0 BC557B
Q4_driver N018 N020 N021 0 BC557B
V2 N021 0 3.5
R5 N020 N016 500
R6 N019 N015 500
R7 N019 N021 500
R8 N020 N021 500
R9 N008 N004 1k
R10 N009 N005 1k
VQ3_ctrl_signal N015 0 PULSE(3.3 0 2 0 0 1 0 1)
VQ1_Ctrl_signal N004 0 PULSE(0 3.3 0 0 0 1 0 1)
VQ4_ctrl_signal N016 0 PULSE(3.3 0 0 0 0 1 0 1)
VQ2_ctrl_signal N005 0 PULSE(0 3.3 2 0 0 1 0 1)
.tran 5

* LTspice schematic (.asc)
Version 4
SHEET 1 3024 1248
WIRE 856 -624 -520 -624
WIRE 216 -544 -1048 -544
WIRE -1048 -480 -1048 -544
WIRE -520 -464 -520 -624
WIRE 408 -416 -56 -416
WIRE 1016 -416 408 -416
WIRE 1112 -416 1016 -416
WIRE -1272 -400 -1448 -400
WIRE -744 -400 -904 -400
WIRE -1048 -352 -1048 -400
WIRE -1448 -336 -1448 -400
WIRE -520 -336 -520 -384
WIRE 1016 -336 1016 -416
WIRE 408 -320 408 -416
WIRE -1272 -304 -1272 -400
WIRE -1224 -304 -1272 -304
WIRE -1112 -304 -1144 -304
WIRE -904 -304 -904 -400
WIRE -744 -288 -744 -400
WIRE -696 -288 -744 -288
WIRE -584 -288 -616 -288
WIRE 856 -288 856 -624
WIRE 952 -288 856 -288
WIRE 216 -272 216 -544
WIRE 344 -272 216 -272
WIRE 536 -272 472 -272
WIRE -1448 -240 -1448 -256
WIRE 952 -224 952 -288
WIRE 1080 -224 1080 -288
WIRE 1080 -224 952 -224
WIRE -1400 -208 -1512 -208
WIRE -1176 -208 -1400 -208
WIRE -904 -192 -904 -224
WIRE 344 -192 344 -272
WIRE 536 -192 536 -272
WIRE 536 -192 344 -192
WIRE -1176 -160 -1176 -208
WIRE -1048 -160 -1048 -256
WIRE -1048 -160 -1176 -160
WIRE -520 -160 -520 -240
WIRE -520 -160 -1048 -160
WIRE 1112 -160 1112 -416
WIRE 1384 -160 1112 -160
WIRE -1400 -144 -1400 -208
WIRE -1512 -112 -1512 -208
WIRE -56 -96 -56 -416
WIRE 1384 -64 1384 -160
WIRE 1384 -64 1288 -64
WIRE 1496 -64 1384 -64
WIRE 408 -48 408 -224
WIRE 456 -48 408 -48
WIRE 616 -48 456 -48
WIRE 744 -48 696 -48
WIRE 936 -48 824 -48
WIRE 1016 -48 1016 -240
WIRE 1016 -48 936 -48
WIRE 936 -16 936 -48
WIRE 1208 -16 936 -16
WIRE 1288 -16 1288 -64
WIRE 1496 -16 1496 -64
WIRE -840 16 -1048 16
WIRE -344 16 -520 16
WIRE 456 16 456 -48
WIRE 1160 16 456 16
WIRE -1048 80 -1048 16
WIRE 1208 80 1208 -16
WIRE 1432 80 1208 80
WIRE -520 96 -520 16
WIRE -1304 144 -1448 144
WIRE 1160 144 1160 16
WIRE 1288 144 1288 48
WIRE 1288 144 1160 144
WIRE 1432 144 1432 80
WIRE 1496 144 1496 48
WIRE 1496 144 1432 144
WIRE -744 160 -904 160
WIRE 1016 160 1016 -48
WIRE 408 176 408 -48
WIRE -1048 208 -1048 160
WIRE -520 208 -520 176
WIRE 952 208 856 208
WIRE 344 224 216 224
WIRE -1448 240 -1448 144
WIRE -904 240 -904 160
WIRE 1288 240 1288 144
WIRE 1496 240 1496 144
WIRE -1304 256 -1304 144
WIRE -1224 256 -1304 256
WIRE -1128 256 -1144 256
WIRE -1112 256 -1128 256
WIRE -744 256 -744 160
WIRE -696 256 -744 256
WIRE -600 256 -616 256
WIRE -584 256 -600 256
WIRE -1128 288 -1128 256
WIRE -600 288 -600 256
WIRE -904 352 -904 320
WIRE 1288 352 1288 304
WIRE 1400 352 1288 352
WIRE 1496 352 1496 304
WIRE 1496 352 1400 352
WIRE -1448 368 -1448 320
WIRE -1512 400 -1512 -32
WIRE -1128 400 -1128 368
WIRE -1128 400 -1512 400
WIRE -1048 400 -1048 304
WIRE -1048 400 -1128 400
WIRE -600 400 -600 368
WIRE -600 400 -1048 400
WIRE -520 400 -520 304
WIRE -520 400 -600 400
WIRE -56 416 -56 -16
WIRE 408 416 408 272
WIRE 408 416 -56 416
WIRE 712 416 408 416
WIRE 1016 416 1016 256
WIRE 1016 416 712 416
WIRE 1400 416 1400 352
WIRE 1400 416 1016 416
WIRE 712 448 712 416
WIRE -840 544 -840 16
WIRE 216 544 216 224
WIRE 216 544 -840 544
WIRE -344 624 -344 16
WIRE 856 624 856 208
WIRE 856 624 -344 624
FLAG 712 448 0
FLAG -1400 -144 0
FLAG -1448 368 0
FLAG -1448 -240 0
FLAG -904 352 0
FLAG -904 -192 0
DATAFLAG -256 528 ""
SYMBOL npn 344 176 R0
SYMATTR InstName Q3
SYMATTR Value 2SCR554P
SYMBOL npn 952 160 R0
SYMATTR InstName Q4
SYMATTR Value 2SCR554P
SYMBOL res 712 -64 R90
SYMATTR InstName Rmotor
SYMATTR Value 1
SYMBOL ind 840 -64 R90
SYMATTR InstName Lmotor
SYMATTR Value .05
SYMBOL voltage -56 -112 R0
SYMATTR InstName V1
SYMATTR Value 5 volt
SYMBOL pnp 1080 -240 R180
SYMATTR InstName Q2
SYMATTR Value 2SAR554P
SYMBOL pnp 472 -224 R180
SYMATTR InstName Q1
SYMATTR Value 2SAR554P
SYMBOL res -504 192 R180
SYMATTR InstName R1
SYMATTR Value 33
SYMBOL res -1032 176 R180
SYMATTR InstName R2
SYMATTR Value 33
SYMBOL res -1032 -384 R180
SYMATTR InstName R3
SYMATTR Value 33
SYMBOL res -504 -368 R180
SYMATTR InstName R4
SYMATTR Value 33
SYMBOL diode 1304 304 R180
SYMATTR InstName D1
SYMBOL diode 1512 304 R180
SYMATTR InstName D2
SYMBOL diode 1304 48 R180
SYMATTR InstName D3
SYMBOL diode 1512 48 R180
SYMATTR InstName D4
SYMBOL npn -1112 -352 R0
SYMATTR InstName Q1_driver
SYMATTR Value BC547B
SYMBOL npn -584 -336 R0
SYMATTR InstName Q2_driver
SYMATTR Value BC547B
SYMBOL pnp -1112 208 R0
SYMATTR InstName Q3_driver
SYMATTR Value BC557B
SYMBOL pnp -584 208 R0
SYMATTR InstName Q4_driver
SYMATTR Value BC557B
SYMBOL voltage -1512 -16 R180
SYMATTR InstName V2
SYMATTR Value 3.5
SYMBOL res -600 240 R90
SYMATTR InstName R5
SYMATTR Value 500
SYMBOL res -1128 240 R90
SYMATTR InstName R6
SYMATTR Value 500
SYMBOL res -1144 272 R0
SYMATTR InstName R7
SYMATTR Value 500
SYMBOL res -616 272 R0
SYMATTR InstName R8
SYMATTR Value 500
SYMBOL res -1128 -320 R90
SYMATTR InstName R9
SYMATTR Value 1k
SYMBOL res -600 -304 R90
SYMATTR InstName R10
SYMATTR Value 1k
SYMBOL voltage -1448 224 R0
SYMATTR InstName Q3_ctrl_signal
SYMATTR Value PULSE(3.3 0 2 0 0 1 0 1)
SYMBOL voltage -1448 -352 R0
SYMATTR InstName Q1_Ctrl_signal
SYMATTR Value PULSE(0 3.3 0 0 0 1 0 1)
SYMBOL voltage -904 224 R0
SYMATTR InstName Q4_ctrl_signal
SYMATTR Value PULSE(3.3 0 0 0 0 1 0 1)
SYMBOL voltage -904 -320 R0
SYMATTR InstName Q2_ctrl_signal
SYMATTR Value PULSE(0 3.3 2 0 0 1 0 1)