diy_timecode_generator

SMPTE standard-compliant DIY LTC timecode generator, that supports framerates of 24, 25, or 30 fps (NDF).

Features

• SMPTE standard-compliant LTC timecode generator

• Supports framerates of 24, 25, or 30 fps (NDF)

• Capability to synchronize multiple generators through WIFI broadcasting

• Constructed with cost-effective components

• Time accuracy with a drift of no more than 1 frames per 8h

• Integrated temperature-compensated crystal oscillator (TCXO)

• Equipped with BNC and 3.5mm audio jack connectivity options

Hardware

• ESP32 (eg. Adafruit Feather, Dealikee ESP-32S or similar)

Important note: Make sure that the board has a LiPo Controller (and connector) and runs on 3V3.
Tested with Dealike ESP-32S.

• 3,7 V 2000mAh 1S Lithium Battery (for ESP32)

• DS3231 Breakout Board (eg. Wishiot DS-3231 RTC, AZDelivery DS3231 RTC or similar)

Important note: Also make sure it runs on 3V3 (they usually do).
Tested with Wishiot DS3231 RTC.

• Perfboard 5x9cm (16x30 perforations)

• 3,5mm Stereo Audio Jack for Perfboard

• BNC Jack for Perfboard

• 3 Position Switch for Perfboard (Type: 2P3T)

• 2 Position Switch for Perfboard (Type: SPDT)

• RGB LED

Make sure it has the following specs:
red = 400 mcd
green = 1500 mcd
blue = 700 mcd

• 3x 220Ω Resistors

• Copper Wire & Solder

• Jumpercables / Cables

Required Boards / Libraries

• ESP32 Boards (https://github.com/espressif/arduino-esp32)

• Wire

• RTClib (https://github.com/adafruit/RTClib)

• esp_now

• WiFi

• esp_timer (https://playground.arduino.cc/Code/Timer1/)

Modified Code

This project uses code sections from this project: (https://github.com/lydasia/openltc), which are marked by comments.

Pin Definitions

• tlcpin : Pin for Timecode Output (default: 4 )

• twentyfour : Switch Input for 24fps (default: 35 )

• twentyfive : Swicth Input for 25fps (default: 34 )

• thirty : Switch Input for 30fps (default: 33 )

• RTCvcc : Power Pin for the RTC (default: 32 )

• LEDR : Output Pin for LED Red Channel (default: 13 )

• LEDG : Output Pin for LED Green Channel (default: 12 )

• LEDB : Output Pin for LED Blue Channel (default: 14 )

Circuit Board Layout

I've made a little change to this layout by connecting the VCC of the RTC to Pin 32 instead of going straight to 3v3. 
This allows for a disabled RTC whenever the device is connected to a lipo battery and not turned on. 
Pin 32 gets HIGH when the ESP32 is booted. Otherwise the RTC would stay on and drain the battery faster.

I cannot guarantee that this code will work for everyone and with different components than the ones I use. Use this code at your own risk.

Housing and final build

I will post my design for the housing box for 3d printing as soon as they are finished.