Specifications
| Type | 4-digit 7-segment LED display with a TM1637 driver chip |
|---|---|
| TinkerBlock TK51 | The clock version: a colon between the middle digits and no decimal points. In the 46-piece kit |
| Clock set | 6 panels with a colon between the middle digits and no decimal points, one each in yellow, green, blue, white, orange and red, with a film cover and a 3D-printed enclosure each |
| Digit set | 6 panels with a decimal point after each digit and no colon, in the same six colours, with a film cover and an enclosure each |
| Driver chip | Titan Micro TM1637, SOP-20, under the display: 8 segments by 6 digits, of which this board uses 4. It drives common-anode displays |
| Wires to your board | 4: GND, VCC, and the 2 signal wires CLOCK and DATA |
| Protocol | Two-wire, TM1637's own. No addresses, so it is not I2C and cannot share an I2C bus |
| Supply voltage | 5 V for every colour. 3.3 V usually lights red, orange, yellow and green; blue and white need 5 V. The datasheet specifies the chip at 4.5 to 5.5 V |
| Pull-ups | 10 kΩ on CLOCK and on DATA, to VCC. So VCC is the voltage your board's two pins see |
| Digit height | 0.56 inch, which is 14.2 mm |
| Brightness | 8 steps, set in software: pulse widths of 1, 2, 4, 10, 11, 12, 13 and 14 sixteenths |
| Header | 4-pin right-angle male at the left end, 2.54 mm: GND, VCC, CLOCK, DATA from the top. No pad is square; the names are printed on the back. The same four are bare pads at the right end |
| Board | 62.3 × 22.4 mm, V3, four 4.6 mm mounting holes 56 × 16 mm apart. Every part is on the display side |
What it does
Four digits, a driver chip and two wires. The chip holds a byte per digit and does the refreshing itself, so your sketch sends a number once and the display keeps showing it through anything else the program goes on to do.
The protocol looks like I2C (a clock line, a data line, a start and a stop) and is not: there is no address anywhere in it. So an I2C scanner will not find this display, it cannot share a bus with I2C parts, and a second display needs a DATA pin of its own.
The boxes
Three products, one board. What differs is the display soldered to it.
The TinkerBlock TK51 is the same board in the 46-piece kit, with the clock display. Its back carries the sentence that explains the whole range: for clock display, decimal points are replaced by colon. There are eight segment wires, and the eighth is either the points or the colon, never both.
| You are showing | The panel | Why |
|---|---|---|
| A time, a timer, minutes and seconds | Clock (and the TK51) | The colon is the only separator that reads as a time |
| A temperature, a voltage, a weight | Digit | 23.5 needs a point, and a colon cannot be one |
| A count, a score, a raw number | Either | Neither separator gets used |
Bit 7 of a digit is that digit's decimal point, and on a clock panel the second
digit's is wired to the colon. 0b01000000, the second digit, is what lights
it. Not 0b10000000, which is the first digit and lights nothing on a clock
panel.
Wiring, in four lines
| Your board | VCC to | CLOCK to | DATA to |
|---|---|---|---|
| Arduino Uno | 5V | D2 | D3 |
| ESP32 | 3V3 | GPIO 18 | GPIO 19 |
| ESP32-S3 | 3V3 | GPIO 4 | GPIO 5 |
| Raspberry Pi Pico (MicroPython) | 3V3(OUT) | GP2 | GP3 |
- GND to your board's GND.
- VCC to your board's logic supply. Never 5V beside a 3.3 V board.
- CLOCK to any digital pin.
- DATA to any other digital pin.
Seen from the display side with the header on the left, the pins read GND, VCC, CLOCK, DATA from the top. No pad is square, so go by the back, which prints GND, VCC, clock, data at both ends. VCC is the one that is not free choice: the board's 10 kΩ pull-ups tie CLOCK and DATA to it.
More than one
Displays share CLOCK and need a DATA pin each: six displays cost seven pins. A display only starts listening when its own DATA falls while CLOCK is high, so the clock toggling for its neighbour means nothing to it.
The four pads at the far end of each board are the same four nets as the header, not a pass-through. They are the right way to pass power and clock along a row, and the wrong way to feed the next display's DATA: wired that way, every panel shows the same number.
Example
Install TM1637 by Avishay Orpaz from the Arduino Library Manager; the
header is TM1637Display.h. The MicroPython version drives the two wires by
hand with tm1637.py from the same folder, saved to the board first.
/*
TM1637 4-Digit Display - colon and points TK51 / /p/tk51
Wiring. No pad on this board is square, so go by the names
printed on the back: GND, VCC, clock, data. Seen from the
display side with the header on the left, GND is the top pin.
GND -> GND
VCC -> your board's logic supply: 5V on an Uno, 3V3 on an
ESP32 or ESP32-S3. Never 5V beside a 3.3 V board:
the pull-ups would put 5 V on your pins.
CLOCK -> D2 on an Uno, GPIO 18 on an ESP32, GPIO 4 on an
ESP32-S3
DATA -> D3 on an Uno, GPIO 19 on an ESP32, GPIO 5 on an
ESP32-S3
Arduino IDE
Tools > Board your board, e.g. Arduino Uno
Tools > Port the one that appears when you plug in
Tools > USB CDC On Boot Enabled (ESP32-S3 only)
Library: "TM1637" by Avishay Orpaz, from Tools > Manage
Libraries. It installs TM1637Display.h.
*/
#include <TM1637Display.h>
#define CLOCK_PIN 2 // Uno D2. ESP32: 18. ESP32-S3: 4.
#define DATA_PIN 3 // Uno D3. ESP32: 19. ESP32-S3: 5.
#define COLON 0b01000000 // bit 7 of the second digit
// CLOCK first, then DATA.
TM1637Display display(CLOCK_PIN, DATA_PIN);
void setup() {
display.setBrightness(4); // 0 to 7, sent with the next write
}
void loop() {
// 12:34 on a clock panel, 12.34 on a digit panel: the same
// four bytes. The colon blinks once a second.
display.showNumberDecEx(1234, COLON, true);
delay(500);
display.showNumberDecEx(1234, 0, true);
delay(500);
}"""
TM1637 4-Digit Display - colon and points TK51 / /p/tk51
Wiring. No pad on this board is square, so go by the names
printed on the back: GND, VCC, clock, data. Seen from the
display side with the header on the left, GND is the top pin.
GND -> GND
VCC -> 3V3 on an ESP32 or ESP32-S3, 3V3(OUT) on a Pico.
Never 5V: the pull-ups would put 5 V on your pins.
CLOCK -> GPIO 18 on an ESP32, GPIO 4 on an ESP32-S3,
GP2 on a Raspberry Pi Pico
DATA -> GPIO 19 on an ESP32, GPIO 5 on an ESP32-S3,
GP3 on a Raspberry Pi Pico
Thonny
Run > Configure interpreter MicroPython (ESP32) or
MicroPython (Raspberry Pi Pico)
Save tm1637.py from this folder to the board first.
"""
import time
from tm1637 import TM1637, COLON
# CLOCK, DATA. ESP32: 18, 19. ESP32-S3: 4, 5. Pico: 2, 3.
display = TM1637(18, 19)
# 12:34 on a clock panel, 12.34 on a digit panel: the same four
# bytes. The colon blinks once a second.
while True:
display.number(1234, COLON, True)
time.sleep_ms(500)
display.number(1234, 0, True)
time.sleep_ms(500)Three things to know
| The colon is 0b01000000 | the second digit's point; the first digit's bit, 0b10000000, lights nothing on a clock panel |
| VCC is the signal level | the pull-ups end at VCC, so 3V3 beside an ESP32 |
| A DATA pin each | displays share CLOCK; the spare pads carry the same DATA |
Where to start
The handbook below is thirteen short articles with a working figure in each. If you only read one, read two sets, one board: it is the difference between the two six-packs and the reason most colons refuse to light. If you want a number on the display now, the first number is the whole build.
When it doesn’t work
- An I2C scan does not find it.
- It never will. The protocol has no addresses at all, which the datasheet says in as many words, so there is nothing for a scan to answer. It uses two ordinary digital pins and the TM1637 library, and it cannot share SDA and SCL with real I2C parts.
- The colon will not light.
- Three causes, in order. The panel is a digit one and has decimal points instead of a colon. Or the mask is 0b10000000, which is the first digit: the colon is the second digit's point, 0b01000000. Or the number is 0 with leading zeros off, which makes the released library drop the dots entirely.
- Can I power it from 5 V next to an ESP32?
- No. The board's 10 kΩ pull-ups tie CLOCK and DATA to its VCC, so from 5 V both wires sit at 5 V against pins rated for 3.3 V. Feed it 3V3, or keep 5 V and put a bidirectional level converter in the two signal wires.
- Which pin is pin 1? None of the pads is square.
- None is: all eight header pads are the same oval. Go by the names on the back. Seen from the display side with the header on the left, GND is the top pin and DATA the bottom one.
- The blue panel is much dimmer than the red one.
- Both are working. Blue and white LEDs need about 3.1 V before they conduct, and there are no series resistors on this board, so 3.3 V leaves almost nothing for the chip's own drivers. Titan Micro's datasheet asks for 5 V where blue is involved.
- setBrightness seems to do nothing.
- The brightness, and the on/off bit with it, is only sent along with digits. Call setBrightness, then show something. On its own it changes a variable inside the library and nothing else.
- Two displays show the same number.
- They are sharing a DATA line. The four pads at the far end of the board are the same four nets as the header, so a second display wired from them hears every byte meant for the first. Displays share CLOCK and need a DATA pin each.
