I was searching for an easy to use LED timer with 3 individual timer times shown at once but I could not find one. So I made this one I would like to share it with you too. =)

Functions:

3 separate timers counting down to 00.00.00.
The remaining time of the timers is shown in the 3 different 8 digit 7-segment displays.
The timers tick down each second.
The timers can be started, stopped and deleted individually.
The running timers can be deleted separately or together.
Planned functions in one of the next versions:
- Notification about the timers with Telegram to your smart phone.
- Hide timer display when timer not set.
- Replace 1,2,3 at the beginning with A,B,C. Currently a bug in the Arduino library.

Usage:

Input:	Result:
A011545	Sets timer A to 1 hour, 15 minutes and 45 seconds and timer starts
B124559	Sets timer B to 12 hours, 45 minutes and 59 seconds and timer starts
C065535	Sets timer C to 6 hours, 55 minutes and 35 seconds and timer starts
DA	Deletes timer A
DB	Deletes timer B
DC	Deletes timer C
DD	Deletes all timers at once

Parts needed:

1x ESP32 NodeMCU
1x 4x4 Matrix keypad
3x MAX7219 LED 7-segment display TM1637
1x Micro-USB cable
1x USB 5V/2A power supply
1x Some wires in different colors
6x M3x35mm countersunk screws
1x Small cable tie to secure the USB cable and ESP32 in the case

Wiring instructions:

ESP32:	Display A:	Display B:	Display C:	Keypad:	Wire color:
3V3	VCC	VCC	VCC		red
GND	GND	GND	GND		black
G27	DIN				green
G12	CS				white
G14	CLK				grey
G33		DIN			green
G26		CS			white
G25		CLK			grey
G15			DIN		green
G32			CS		white
G13			CLK		grey
G19				1	white
G18				2	brown
G5				3	orange
G17				4	grey
G16				5	yellow
G4				6	purple
G0				7	blue
G2				8	green