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Introduction
History: how light learned to count people
Lesson 0. Gates from transistors: for those who start from scratch
0.1. The idea: a transistor is a switch
0.2. Building
0.3. Check
Lesson 0 paste (Cmd+I)
Lesson 1. The beam and CD4011
1.1. Idea: how a shop counts people
1.2. Idea: the CMOS 4000 series
1.3. Idea: NAND for everything
1.4. Build
1.5. Check
Lesson 1 paste (Cmd+I)
Lesson 2. The F/F flip-flop
2.1. Idea: a counter is flip-flops that flip
2.2. Idea: flipping through exclusive OR
2.3. Idea: a NAND with three inputs
2.4. Build
2.5. Check
Lesson 2 paste (Cmd+I)
Lesson 3. The CD4029B counter
3.1. Idea: which bit to flip
3.2. Idea: controlling the counter
3.3. Idea: the bubbles on the TI drawing
3.4. Build
3.5. Check
Lesson 3 paste (Cmd+I)
Lesson 4. The CD4511B decoder
4.1. Idea: seven strokes
4.2. Idea: latch, blanking, lamp test
4.3. Idea: a switch on two transistors
4.4. Build
4.5. Check
Lesson 4 paste (Cmd+I)
Lesson 5. Direction
5.1. Idea: two beams one after another
5.2. Idea: remember the first
5.3. Idea: the clock is when both are blocked
5.4. Build
5.5. Check
Lesson 5 paste (Cmd+I)
Lesson 6. The visitor counter
6.1. Idea: two displays on the same beams
6.2. Idea: two digits — two counters
6.3. Idea: Reset holds
6.4. Build
6.5. Check
Lesson 6 paste (Cmd+I)
Summary
All the parts
Instructions in pictures
Instructions in pictures
Download PDF — the whole book
kh
HOW THINGS WORK
build kits · khanin.info
Building
instructions
HT-04
The Visitor Counter
lessons 0–6 · two beams and three chips
simulator: cs.khanin.info
© 2026 Daniil Khanin · khanin.info · HT-04
1
How to read these instructions
3
step number — follow strictly in order
AND
2×
6×
parts for this step: how many to place
AND
A
x
B
y
Y
z
a part with labels on its pins
CLK
CLK
labels with the same name are connected
A
Y
chip ports: input [ and output ]
DFF
blue frame — building a chip
CANVAS
grey tab — the main canvas
low
yellow ring — what has changed
remove a part together with its labels
2×
double-click a label — new name
3
chip built in the lesson with this number
check: this is how it should work
Keys
V
VCC (1)
G
GND (0)
N
transistor
I
switch
O
lamp
L
label
K
clock
U
button
[
port in
]
port out
Ctrl+G — into a chip
on a Mac Ctrl = Cmd
© 2026 Daniil Khanin · khanin.info · HT-04
2
A little history
1873
selenium
1905
Einstein
1930s
"electric eye"
1962
IR LED
1968
CMOS 4000
In 1873 selenium was found to conduct in light. In 1905 Einstein explained
the photoelectric effect: light comes in portions and knocks charges out of metal —
he got the Nobel Prize for it.
In the 1930s the "electric eye" — a photocell, an amplifier and a lamp opposite —
opened doors and clicked a counter when someone crossed the beam. Two beams in a row
also tell the direction: the first one blocked is where people come from.
In 1962 Texas Instruments made the infrared LED — the beam became invisible.
In 1968 RCA released CMOS 4000: you build its CD4029 counter and CD4511 decoder —
after the datasheet, with the same pins.
Segment LCD
Albert Einstein, 1921 · photo by F. Schmutzer
A
B
CD4011
CD4029
RCA, Texas Instruments are trademarks of their respective owners. This kit is not affiliated with or endorsed by them; the names are mentioned to tell the story.
© 2026 Daniil Khanin · khanin.info · HT-04
3
0
Gates (optional)
NOT, NAND, NOR, AND, OR, XOR from transistors
kh
HT-04
NOT
NAND
NOR
AND
OR
XOR
IN
11×
OUT
6×
P
11×
N
11×
∞
Ctrl
+
G
NOT
NAND
NOR
AND
OR
XOR
© 2026 Daniil Khanin · khanin.info · HT-04
4
NOT
1
IN
1×
OUT
1×
P
1×
N
1×
6×
I0
O0
VCC
O0
G
P
I0
O0
GND
G
N
I0
2
Ctrl
+
G
Library
…
Chip N
2×
Library
…
NOT
Enter
NOT
I0
O0
© 2026 Daniil Khanin · khanin.info · HT-04
5
NAND
3
IN
2×
OUT
1×
P
2×
N
1×
9×
I0
I1
O0
VCC
O0
G
P
I0
VCC
O0
G
P
I1
O0
mid
G
N
I0
4
N
1×
3×
mid
GND
G
N
I1
5
Ctrl
+
G
Library
…
Chip N
2×
Library
…
NAND
Enter
NAND
I0
I1
O0
© 2026 Daniil Khanin · khanin.info · HT-04
6
NOR
6
IN
2×
OUT
1×
P
2×
N
1×
9×
I0
I1
O0
VCC
mid
G
P
I0
mid
O0
G
P
I1
O0
GND
G
N
I0
7
N
1×
3×
O0
GND
G
N
I1
8
Ctrl
+
G
Library
…
Chip N
2×
Library
…
NOR
Enter
NOR
I0
I1
O0
© 2026 Daniil Khanin · khanin.info · HT-04
7
AND
9
IN
2×
OUT
1×
P
2×
N
1×
9×
I0
I1
O0
VCC
n
G
P
I0
VCC
n
G
P
I1
n
mid
G
N
I0
10
N
2×
P
1×
9×
mid
GND
G
N
I1
VCC
O0
G
P
n
O0
GND
G
N
n
11
Ctrl
+
G
Library
…
Chip N
2×
Library
…
AND
Enter
AND
I0
I1
O0
© 2026 Daniil Khanin · khanin.info · HT-04
8
OR
12
IN
2×
OUT
1×
P
2×
N
1×
9×
I0
I1
O0
VCC
mid
G
P
I0
mid
n
G
P
I1
n
GND
G
N
I0
13
N
2×
P
1×
9×
n
GND
G
N
I1
VCC
O0
G
P
n
O0
GND
G
N
n
14
Ctrl
+
G
Library
…
Chip N
2×
Library
…
OR
Enter
OR
I0
I1
O0
© 2026 Daniil Khanin · khanin.info · HT-04
9
XOR
15
IN
2×
OUT
1×
OR
1×
NAND
1×
AND
1×
9×
I0
I1
O0
OR
I0
I0
I1
I1
O0
o
NAND
I0
I0
I1
I1
O0
n
AND
I0
o
I1
n
O0
O0
16
Ctrl
+
G
Library
…
Chip N
2×
Library
…
XOR
Enter
XOR
I0
I1
O0
© 2026 Daniil Khanin · khanin.info · HT-04
10
1
The beam and CD4011
an IR pair and the "someone passed" latch
kh
HT-04
CD4011
A
B
IN
8×
OUT
4×
NAND
4×
0
VCC
1×
GND
1×
E
1×
R
1×
Q
Q
1×
2×
∞
Ctrl
+
G
CD4011
© 2026 Daniil Khanin · khanin.info · HT-04
11
CANVAS
CD4011
1
pin names as in the TI datasheet; a bar over a name in the picture = active 0, in the simulator without the bar
2
IN
8×
OUT
4×
A
B
C
D
E
F
G
H
J
K
L
M
3
NAND
3×
0
9×
NAND
I0
A
I1
B
O0
J
NAND
I0
C
I1
D
O0
K
NAND
I0
E
I1
F
O0
L
© 2026 Daniil Khanin · khanin.info · HT-04
12
CD4011 …
CANVAS
4
NAND
1×
0
3×
NAND
I0
G
I1
H
O0
M
5
Ctrl
+
G
Library
…
Chip N
2×
Library
…
CD4011
Enter
CD4011
A
B
C
D
E
F
G
H
J
K
L
M
6
Sensors → IR pair: E and R are placed together, the channel is the pair number
7
VCC
1×
GND
1×
2×
VCC
VCC
GND
GND
© 2026 Daniil Khanin · khanin.info · HT-04
13
CANVAS …
8
E
1×
R
1×
Q
Q
1×
3×
VCC
E1
R1
BA
Reset
Reset
RST
9
CD4011
1×
12×
CD4011
A
BA
B
BA
C
RST
D
RST
E
BA
F
SEENN
G
nRST
H
SEEN
J
XA
K
nRST
L
SEEN
M
SEENN
10
2×
2×
XA
SEEN
A
B
XA
SEEN
press the beam — XA and SEEN
let go — SEEN stays
Reset — off
11
Alt/⌘ + click on a beam — blocked and fixed; again — cleared
© 2026 Daniil Khanin · khanin.info · HT-04
14
2
The F/F flip-flop
load, flip, hold
kh
HT-04
F/F
Q
Q
Q
Q
IN
7×
OUT
3×
P
3×
N
3×
NOT
4×
0
NAND
2×
0
XOR
1×
0
0
3×
Hz
1×
3×
∞
Ctrl
+
G
NAND3
FF4029
© 2026 Daniil Khanin · khanin.info · HT-04
15
CANVAS
1
Delete
VCC
E1
R1
BA
Reset
Reset
RST
XA
SEEN
2
Delete
CD4011
A
BA
B
BA
C
RST
D
RST
E
BA
F
SEENN
G
nRST
H
SEEN
J
XA
K
nRST
L
SEEN
M
SEENN
© 2026 Daniil Khanin · khanin.info · HT-04
16
NAND3
3
IN
3×
OUT
1×
P
3×
9×
A
B
C
Y
Y
VCC
G
P
A
Y
VCC
G
P
B
Y
VCC
G
P
C
4
N
3×
9×
Y
m1
G
N
A
m1
m2
G
N
B
m2
GND
G
N
C
5
Ctrl
+
G
Library
…
Chip N
2×
Library
…
NAND3
Enter
NAND3
A
B
C
Y
© 2026 Daniil Khanin · khanin.info · HT-04
17
FF4029
6
IN
4×
OUT
2×
NOT
3×
0
6×
PE
J
TE
CL
Q
QN
NOT
I0
CL
O0
cp
NOT
I0
PE
O0
ld
NOT
I0
J
O0
jn
7
NAND
2×
0
XOR
1×
0
9×
NAND
I0
ld
I1
jn
O0
sdn
NAND
I0
ld
I1
J
O0
rdn
XOR
I0
Q
I1
TE
O0
x
© 2026 Daniil Khanin · khanin.info · HT-04
18
FF4029 …
8
NOT
1×
0
2×
NOT
I0
x
O0
d
9
NAND3
3×
12×
NAND3
A
sdn
B
n4
C
n2
Y
n1
NAND3
A
n1
B
rdn
C
cp
Y
n2
NAND3
A
n2
B
cp
C
n4
Y
n3
10
NAND3
3×
12×
NAND3
A
n3
B
rdn
C
d
Y
n4
NAND3
A
sdn
B
n2
C
QN
Y
Q
NAND3
A
Q
B
n3
C
rdn
Y
QN
© 2026 Daniil Khanin · khanin.info · HT-04
19
FF4029 …
CANVAS
11
Ctrl
+
G
Library
…
Chip N
2×
Library
…
FF4029
Enter
FF4029
PE
J
TE
CL
Q
QN
12
1
1Hz
2Hz
10Hz
60Hz
4kHz
…
MAX
13
0
3×
Hz
1×
4×
0
PE
0
J
0
TE
1Hz
CL
14
FF4029
1×
6×
FF4029
PE
PE
J
J
TE
TE
CL
CL
Q
Q
QN
QN
© 2026 Daniil Khanin · khanin.info · HT-04
20
CANVAS …
15
3×
3×
CL
Q
QN
1
PE
0
TE
Q
PE = 1, TE = 0: Q blinks half as often as CL
© 2026 Daniil Khanin · khanin.info · HT-04
21
3
The CD4029 counter
up and down, binary and decade
kh
HT-04
CD4029
Q4
Q3
Q2
Q1
IN
16×
OUT
7×
P
7×
N
7×
NOT
27×
0
NAND
2×
0
FF4029
4×
2
NAND3
2×
2
AND
9×
0
NOR
7×
0
OR
2×
0
0
8×
Hz
1×
6×
∞
Ctrl
+
G
NOR3
NOR4
CD4029
© 2026 Daniil Khanin · khanin.info · HT-04
22
CANVAS
1
Delete
0
PE
0
J
0
TE
1Hz
CL
FF4029
PE
PE
J
J
TE
TE
CL
CL
Q
Q
QN
QN
CL
Q
QN
© 2026 Daniil Khanin · khanin.info · HT-04
23
NOR3
2
IN
3×
OUT
1×
P
3×
9×
A
B
C
Y
VCC
p1
G
P
A
p1
p2
G
P
B
p2
Y
G
P
C
3
N
3×
9×
Y
GND
G
N
A
Y
GND
G
N
B
Y
GND
G
N
C
4
Ctrl
+
G
Library
…
Chip N
2×
Library
…
NOR3
Enter
NOR3
A
B
C
Y
© 2026 Daniil Khanin · khanin.info · HT-04
24
NOR4
5
IN
4×
OUT
1×
P
3×
9×
A
B
C
D
Y
VCC
p1
G
P
A
p1
p2
G
P
B
p2
p3
G
P
C
6
P
1×
N
2×
9×
p3
Y
G
P
D
Y
GND
G
N
A
Y
GND
G
N
B
© 2026 Daniil Khanin · khanin.info · HT-04
25
NOR4 …
CANVAS
7
N
2×
6×
Y
GND
G
N
C
Y
GND
G
N
D
8
Ctrl
+
G
Library
…
Chip N
2×
Library
…
NOR4
Enter
NOR4
A
B
C
D
Y
9
pin names as in the TI datasheet; a bar over a name in the picture = active 0, in the simulator without the bar
© 2026 Daniil Khanin · khanin.info · HT-04
26
CD4029
10
IN
9×
OUT
5×
PE
J4
J1
CI
BD
UD
J2
J3
CLOCK
Q4
Q1
CO
Q2
Q3
11
NOT
3×
0
6×
NOT
I0
BD
O0
nBD
NOT
I0
nBD
O0
A
NOT
I0
PE
O0
E
12
NOT
3×
0
6×
NOT
I0
CI
O0
nCI
NOT
I0
UD
O0
nUD
NOT
I0
nUD
O0
U
© 2026 Daniil Khanin · khanin.info · HT-04
27
CD4029 …
13
NOT
2×
0
NAND
1×
0
7×
NOT
I0
CLOCK
O0
nCLK
NAND
I0
E
I1
nCLK
O0
ncl
NOT
I0
ncl
O0
CL
14
NOT
3×
0
6×
NOT
I0
J1
O0
j1
NOT
I0
J2
O0
j2
NOT
I0
J3
O0
j3
15
NOT
1×
0
2×
NOT
I0
J4
O0
j4
16
FF4029
2×
2
12×
FF4029
PE
E
J
j1
TE
CI
CL
CL
Q
q1
QN
q1n
FF4029
PE
E
J
j2
TE
te2
CL
CL
Q
D
QN
J
© 2026 Daniil Khanin · khanin.info · HT-04
28
CD4029 …
17
FF4029
2×
2
12×
FF4029
PE
E
J
j3
TE
G
CL
CL
Q
B
QN
I
FF4029
PE
E
J
j4
TE
te4
CL
CL
Q
C
QN
q4n
18
NAND3
2×
2
NOT
1×
0
10×
NAND3
A
nCI
B
nUD
C
q1n
Y
nf
NOT
I0
nf
O0
F
NAND3
A
q1
B
nCI
C
U
Y
nl
19
NOT
1×
0
2×
NOT
I0
nl
O0
L
© 2026 Daniil Khanin · khanin.info · HT-04
29
CD4029 …
20
NOR4
1×
NOT
1×
0
7×
NOR4
A
A
B
B
C
C
D
D
Y
bout
NOT
I0
bout
O0
nbout
21
AND
2×
0
NAND
1×
0
9×
AND
I0
nbout
I1
F
O0
ta
NAND
I0
nBD
I1
C
O0
md
AND
I0
L
I1
md
O0
tb
22
NOR
1×
0
3×
NOR
I0
ta
I1
tb
O0
te2
© 2026 Daniil Khanin · khanin.info · HT-04
30
CD4029 …
23
NOR
1×
0
AND
2×
0
9×
NOR
I0
bout
I1
D
O0
te_
AND
I0
F
I1
te_
O0
tg
AND
I0
D
I1
L
O0
tf
24
NOR
1×
0
3×
NOR
I0
tg
I1
tf
O0
G
25
NOR
1×
0
NOT
1×
0
OR
1×
0
8×
NOR
I0
J
I1
I
O0
th
NOT
I0
md
O0
nmd
OR
I0
th
I1
nmd
O0
H
© 2026 Daniil Khanin · khanin.info · HT-04
31
CD4029 …
26
NOR
1×
0
AND
2×
0
9×
NOR
I0
D
I1
B
O0
tp
AND
I0
F
I1
tp
O0
tq
AND
I0
H
I1
L
O0
tr
27
NOR
1×
0
3×
NOR
I0
tq
I1
tr
O0
te4
28
NOR3
1×
AND
1×
0
NOT
1×
0
9×
NOR3
A
B
B
D
C
C
Y
tv
AND
I0
F
I1
tv
O0
tw
NOT
I0
A
O0
an
© 2026 Daniil Khanin · khanin.info · HT-04
32
CD4029 …
29
OR
1×
0
AND
2×
0
9×
OR
I0
an
I1
th
O0
tt
AND
I0
C
I1
tt
O0
tu
AND
I0
L
I1
tu
O0
tx
30
NOR
1×
0
NOT
2×
0
7×
NOR
I0
tw
I1
tx
O0
co0
NOT
I0
co0
O0
co1
NOT
I0
co1
O0
CO
31
NOT
3×
0
6×
NOT
I0
q1
O0
o1
NOT
I0
o1
O0
Q1
NOT
I0
D
O0
o2
32
NOT
3×
0
6×
NOT
I0
o2
O0
Q2
NOT
I0
B
O0
o3
NOT
I0
o3
O0
Q3
© 2026 Daniil Khanin · khanin.info · HT-04
33
CD4029 …
CANVAS
33
NOT
2×
0
4×
NOT
I0
C
O0
o4
NOT
I0
o4
O0
Q4
34
Ctrl
+
G
Library
…
Chip N
2×
Library
…
CD4029
Enter
CD4029
PE
J4
J1
CI
BD
UD
J2
J3
CLOCK
Q4
Q1
CO
Q2
Q3
35
1
1Hz
2Hz
10Hz
60Hz
4kHz
…
MAX
36
0
5×
5×
0
PE
0
J1
0
J2
0
J3
0
J4
37
0
3×
Hz
1×
4×
0
CI
0
BD
0
UD
1Hz
CLOCK
© 2026 Daniil Khanin · khanin.info · HT-04
34
CANVAS …
38
CD4029
1×
14×
CD4029
PE
PE
J4
J4
J1
J1
CI
CI
BD
BD
UD
UD
J2
J2
J3
J3
CLOCK
CLOCK
Q4
Q4
Q1
Q1
CO
CO
Q2
Q2
Q3
Q3
39
5×
5×
CLOCK
Q4
Q3
Q2
Q1
40
1×
1×
CO
0
BD
1
UD
Q4
Q3
Q2
Q1
BD = 0, UD = 1: 0 → 9 → 0
© 2026 Daniil Khanin · khanin.info · HT-04
35
4
The CD4511 decoder
a binary code → a digit on the display
kh
HT-04
CD4511
IN
10×
OUT
8×
N
1×
P
1×
NOT
22×
0
NOR3
8×
3
NOR
9×
0
NAND
3×
0
NOR4
6×
3
0
1×
Hz
1×
Q
Q
1×
CD4029
1×
3
∞
Ctrl
+
G
TG
CD4511
© 2026 Daniil Khanin · khanin.info · HT-04
36
CANVAS
1
Delete
0
PE
0
J1
0
J2
0
J3
0
J4
0
CI
0
BD
0
UD
1Hz
CLOCK
2
Delete
CLOCK
Q4
Q3
Q2
Q1
CO
3
Delete
CD4029
PE
PE
J4
J4
J1
J1
CI
CI
BD
BD
UD
UD
J2
J2
J3
J3
CLOCK
CLOCK
Q4
Q4
Q1
Q1
CO
CO
Q2
Q2
Q3
Q3
© 2026 Daniil Khanin · khanin.info · HT-04
37
TG
4
IN
3×
OUT
1×
N
1×
P
1×
6×
A
N
P
B
A
B
G
N
N
A
B
G
P
P
5
Ctrl
+
G
Library
…
Chip N
2×
Library
…
TG
Enter
TG
A
N
P
B
© 2026 Daniil Khanin · khanin.info · HT-04
38
CANVAS
CD4511
6
pin names as in the TI datasheet; a bar over a name in the picture = active 0, in the simulator without the bar
7
IN
7×
OUT
7×
B
C
LT
BL
LE
D
A
e
d
c
b
a
g
f
8
NOT
3×
0
6×
NOT
I0
A
O0
n1
NOT
I0
B
O0
n2
NOT
I0
C
O0
n3
9
NOT
2×
0
TG
1×
8×
NOT
I0
D
O0
n4
NOT
I0
LE
O0
n5
TG
A
n1
N
n5
P
n6
B
n7
© 2026 Daniil Khanin · khanin.info · HT-04
39
CD4511 …
10
TG
3×
12×
TG
A
n2
N
n5
P
n6
B
n8
TG
A
n3
N
n5
P
n6
B
n9
TG
A
n4
N
n5
P
n6
B
n10
11
NOT
2×
0
TG
1×
8×
NOT
I0
n5
O0
n6
TG
A
n11
N
n6
P
n5
B
n7
NOT
I0
n7
O0
n12
12
NOT
2×
0
TG
1×
8×
NOT
I0
n12
O0
n11
TG
A
n13
N
n6
P
n5
B
n8
NOT
I0
n8
O0
n14
© 2026 Daniil Khanin · khanin.info · HT-04
40
CD4511 …
13
NOT
2×
0
TG
1×
8×
NOT
I0
n14
O0
n13
TG
A
n15
N
n6
P
n5
B
n9
NOT
I0
n9
O0
n16
14
NOT
2×
0
TG
1×
8×
NOT
I0
n16
O0
n15
TG
A
n17
N
n6
P
n5
B
n10
NOT
I0
n10
O0
n18
© 2026 Daniil Khanin · khanin.info · HT-04
41
CD4511 …
15
NOT
1×
0
NOR3
1×
3
NOR
1×
0
9×
NOT
I0
n18
O0
n17
NOR3
A
n11
B
n13
C
n15
Y
n19
NOR
I0
n13
I1
n16
O0
n20
16
NOR3
3×
3
12×
NOR3
A
n15
B
n13
C
n12
Y
n21
NOR3
A
n11
B
n14
C
n15
Y
n22
NOR3
A
n12
B
n14
C
n15
Y
n23
© 2026 Daniil Khanin · khanin.info · HT-04
42
CD4511 …
17
NOR3
2×
3
NAND
1×
0
11×
NOR3
A
n12
B
n13
C
n16
Y
n24
NOR3
A
n11
B
n14
C
n16
Y
n25
NAND
I0
n15
I1
n13
O0
n26
18
NAND
1×
0
NOR4
1×
3
8×
NAND
I0
n26
I1
n18
O0
n27
NOR4
A
n11
B
n14
C
n16
D
n18
Y
n28
19
NOR4
1×
3
NAND
1×
0
8×
NOR4
A
n12
B
n14
C
n16
D
n18
Y
n29
NAND
I0
BL
I1
n27
O0
n30
© 2026 Daniil Khanin · khanin.info · HT-04
43
CD4511 …
20
NOR4
1×
3
NOR3
1×
3
9×
NOR4
A
n30
B
n23
C
n21
D
n28
Y
n31
NOR3
A
n30
B
n22
C
n21
Y
n32
21
NOR
1×
0
NOR4
1×
3
8×
NOR
I0
n30
I1
n24
O0
n33
NOR4
A
n30
B
n23
C
n19
D
n25
Y
n34
22
NOR3
1×
3
NOR4
1×
3
9×
NOR3
A
n30
B
n12
C
n23
Y
n35
NOR4
A
n30
B
n28
C
n20
D
n19
Y
n36
© 2026 Daniil Khanin · khanin.info · HT-04
44
CD4511 …
23
NOR4
1×
3
NOR
1×
0
8×
NOR4
A
n30
B
n19
C
n28
D
n29
Y
n37
NOR
I0
n31
I1
n38
O0
n39
24
NOR
3×
0
9×
NOR
I0
n32
I1
n38
O0
n40
NOR
I0
n33
I1
n38
O0
n41
NOR
I0
n34
I1
n38
O0
n42
25
NOR
3×
0
9×
NOR
I0
n35
I1
n38
O0
n43
NOR
I0
n36
I1
n38
O0
n44
NOR
I0
n37
I1
n38
O0
n45
26
NOT
3×
0
6×
NOT
I0
LT
O0
n38
NOT
I0
n39
O0
a
NOT
I0
n40
O0
b
© 2026 Daniil Khanin · khanin.info · HT-04
45
CD4511 …
CANVAS
27
NOT
3×
0
6×
NOT
I0
n41
O0
c
NOT
I0
n42
O0
d
NOT
I0
n43
O0
e
28
NOT
2×
0
4×
NOT
I0
n44
O0
f
NOT
I0
n45
O0
g
29
Ctrl
+
G
Library
…
Chip N
2×
Library
…
CD4511
Enter
CD4511
B
C
LT
BL
LE
D
A
e
d
c
b
a
g
f
30
1
1Hz
2Hz
10Hz
60Hz
4kHz
…
MAX
© 2026 Daniil Khanin · khanin.info · HT-04
46
CANVAS …
31
0
1×
Hz
1×
Q
Q
1×
3×
0
UD
1Hz
CLOCK
Reset
Reset
RST
32
CD4029
1×
3
13×
CD4029
PE
RST
J4
GND
J1
GND
CI
GND
BD
GND
UD
UD
J2
GND
J3
GND
CLOCK
CLOCK
Q4
U3
Q1
U0
CO
Q2
U1
Q3
U2
33
CD4511
1×
14×
CD4511
B
U1
C
U2
LT
VCC
BL
VCC
LE
GND
D
U3
A
U0
e
Ue
d
Ud
c
Uc
b
Ub
a
Ua
g
Ug
f
Uf
© 2026 Daniil Khanin · khanin.info · HT-04
47
CANVAS …
34
Segment LCD
Size
24
×
30
Enter
35
Stamps
S
M
L 21
Digits
Esc
36
S
Enter
New pin
a
Enter
7×
a
b
c
d
e
f
g
37
7×
Segment LCD
Ua
a
Ub
b
Uc
c
Ud
d
Ue
e
Uf
f
Ug
g
© 2026 Daniil Khanin · khanin.info · HT-04
48
CANVAS …
1
UD
…
UD = 1: 0 → 9
38
delete the probe, keep the display (without labels)
© 2026 Daniil Khanin · khanin.info · HT-04
49
5
Direction
two beams: which one is blocked first
kh
HT-04
A
B
A
B
A
B
VCC
1×
GND
1×
E
2×
R
2×
CD4011
2×
1
5×
∞
© 2026 Daniil Khanin · khanin.info · HT-04
50
CANVAS
1
Delete
0
UD
1Hz
CLOCK
Reset
Reset
RST
2
Delete
CD4029
PE
RST
J4
GND
J1
GND
CI
GND
BD
GND
UD
UD
J2
GND
J3
GND
CLOCK
CLOCK
Q4
U3
Q1
U0
CO
Q2
U1
Q3
U2
CD4511
B
U1
C
U2
LT
VCC
BL
VCC
LE
GND
D
U3
A
U0
e
Ue
d
Ud
c
Uc
b
Ub
a
Ua
g
Ug
f
Uf
© 2026 Daniil Khanin · khanin.info · HT-04
51
CANVAS …
3
pairs one under the other: beam A on top (street), beam B below (shop floor)
4
VCC
1×
GND
1×
2×
VCC
VCC
GND
GND
5
E
2×
R
1×
3×
VCC
E1
R1
BA
VCC
E2
6
R
1×
1×
R2
BB
7
CD4011
1×
1
12×
CD4011
A
BA
B
BA
C
BB
D
BB
E
XA
F
BB
G
XB
H
BA
J
XA
K
XB
L
SIN
M
SOUT
© 2026 Daniil Khanin · khanin.info · HT-04
52
CANVAS …
8
CD4011
1×
1
12×
CD4011
A
SIN
B
OUT
C
SOUT
D
IN
E
XA
F
XB
G
NBOTH
H
NBOTH
J
IN
K
OUT
L
NBOTH
M
BOTH
9
5×
5×
XA
XB
IN
OUT
BOTH
10
Alt/⌘ + click on a beam — blocked and fixed; again — cleared
A
B
A
B
A
B
A, both, B — IN, BOTH, OUT
IN
BOTH
OUT
© 2026 Daniil Khanin · khanin.info · HT-04
53
6
The visitor counter
"inside" and "total in" displays
kh
HT-04
A
B
INSIDE
TOTAL IN
Q
Q
1×
CD4029
4×
3
CD4511
4×
4
∞
© 2026 Daniil Khanin · khanin.info · HT-04
54
CANVAS
1
Q
Q
1×
1×
Reset
Reset
RESET
2
CD4029
1×
3
14×
CD4029
PE
RESET
J4
GND
J1
GND
CI
GND
BD
GND
UD
IN
J2
GND
J3
GND
CLOCK
BOTH
Q4
U3
Q1
U0
CO
COU
Q2
U1
Q3
U2
3
CD4029
1×
3
14×
CD4029
PE
RESET
J4
GND
J1
GND
CI
COU
BD
GND
UD
IN
J2
GND
J3
GND
CLOCK
BOTH
Q4
T3
Q1
T0
CO
COT
Q2
T1
Q3
T2
4
CD4029
1×
3
14×
CD4029
PE
RESET
J4
GND
J1
GND
CI
OUT
BD
GND
UD
VCC
J2
GND
J3
GND
CLOCK
BOTH
Q4
V3
Q1
V0
CO
COV
Q2
V1
Q3
V2
© 2026 Daniil Khanin · khanin.info · HT-04
55
CANVAS …
5
CD4029
1×
3
14×
CD4029
PE
RESET
J4
GND
J1
GND
CI
COV
BD
GND
UD
VCC
J2
GND
J3
GND
CLOCK
BOTH
Q4
W3
Q1
W0
CO
COW
Q2
W1
Q3
W2
6
CD4511
1×
4
14×
CD4511
B
U1
C
U2
LT
VCC
BL
VCC
LE
GND
D
U3
A
U0
e
Ue
d
Ud
c
Uc
b
Ub
a
Ua
g
Ug
f
Uf
© 2026 Daniil Khanin · khanin.info · HT-04
56
CANVAS …
7
CD4511
1×
4
14×
CD4511
B
T1
C
T2
LT
VCC
BL
VCC
LE
GND
D
T3
A
T0
e
Te
d
Td
c
Tc
b
Tb
a
Ta
g
Tg
f
Tf
8
CD4511
1×
4
14×
CD4511
B
V1
C
V2
LT
VCC
BL
VCC
LE
GND
D
V3
A
V0
e
Ve
d
Vd
c
Vc
b
Vb
a
Va
g
Vg
f
Vf
9
CD4511
1×
4
14×
CD4511
B
W1
C
W2
LT
VCC
BL
VCC
LE
GND
D
W3
A
W0
e
We
d
Wd
c
Wc
b
Wb
a
Wa
g
Wg
f
Wf
10
Reset — press and let go: while pressed, the displays stay at 00
11
the lesson 4 display — Cmd+C, Cmd+V: legs a–g are already named
12
displays in pairs: tens on the left, units on the right; "inside" on top
© 2026 Daniil Khanin · khanin.info · HT-04
57
CANVAS …
13
7×
Segment LCD
Ta
a
Tb
b
Tc
c
Td
d
Te
e
Tf
f
Tg
g
14
7×
Segment LCD
Ua
a
Ub
b
Uc
c
Ud
d
Ue
e
Uf
f
Ug
g
15
7×
Segment LCD
Wa
a
Wb
b
Wc
c
Wd
d
We
e
Wf
f
Wg
g
16
7×
Segment LCD
Va
a
Vb
b
Vc
c
Vd
d
Ve
e
Vf
f
Vg
g
in
A
B
inside
total
out
A
B
inside
total
© 2026 Daniil Khanin · khanin.info · HT-04
58
Kit parts
how many times you place each part over all the lessons
N
22×
P
22×
VCC
2×
GND
2×
0
12×
E
3×
R
3×
16×
Hz
3×
Q
Q
3×
IN
52×
OUT
28×
762×
© 2026 Daniil Khanin · khanin.info · HT-04
59
Kit chips
you build them yourself: each one is made of the ones before
OR
3×
0
NAND
12×
0
AND
10×
0
NOT
53×
0
XOR
1×
0
NOR
16×
0
CD4011
3×
1
NAND3
8×
2
FF4029
5×
2
NOR4
7×
3
NOR3
9×
3
CD4029
6×
3
TG
8×
4
CD4511
5×
4
© 2026 Daniil Khanin · khanin.info · HT-04
60
Done!
A
B
INSIDE
TOTAL IN
two displays of 2,664 transistors
walk a person through: A, B, clear A, clear B
© 2026 Daniil Khanin · khanin.info · HT-04
61
Copyright
© 2026 Daniil Khanin, khanin.info. All rights reserved.
These instructions, the drawings and circuits are original work.
Reprinting, publishing online, selling or passing it on to others,
in whole or in part, is prohibited without the written permission of the author.
The latest version is at khanin.info.
kh
khanin.info
HT-04
© 2026 Daniil Khanin · khanin.info · HT-04
62