• ESP-NTP-DCF77-Encoder.
• ESP NTP Clock Encoder Injecting / Transmitting DCF77 (Bye pin or external AM Transmitter).
• Time part working with ezTime = Auto TZ, DLS and much more goodies.
• Using ezTimes "setEvent(advance,now()+1);" as Second ticker for the DCF keying.
• Constant looping / keying / sending next minute.
• Using switch for keying DCF and calculating the DCF arrey:
• case 3: Waiting for the first 59 second after boot and keying out 100 ms until second 58.
• case 2: Long pulse Modulation: 200 ms
• case 1: Short pulse Modulation: 100 ms
• case 0: Reading time and calculate the DCF array the next minute ( = in all 59 Seconds)
• First minute after boot waiting for second 59 before start keying time out DCF time.
• Using ezTime variables for calculating DLS on / off and Summer / Winter Time Announcement.
• Also, for Day of week in DCF format.
• Arduino OTA (Minimum delay in main loop and other places for OTA to working).
• Not implanted: Sec 19, Leap Second announcement (inserting a mark in Sec 59 and sending minute sync in (not existing)Sec 60.
• ezTime rolls over (32 bit signed integer overflows) in 7th of February 2036 and 19th of January 2038,
• so some thing like these can being good to putting in:
• #define MIN_TIME 1582165202 // Date and time (GMT): Thursday, February 20, 2020 2:20:02 AM
• #define MAX_TIME 2082762061 // Date and time (GMT): Tuesday, January 1, 2036 1:01:01 AM
• if (processedTime<MIN_TIME || processedTime>MAX_TIME) {
• Serial.println("You being out of time !!!");
• }
• NTP update inside ezTime (If to much drift it can being problem with the timing of the DCF keying,
• also if problem with NTP update its taking to long or not working (NTP Server or network problems).
• If NTP not getting time sync then boot its retrying until its getting time before entering main loop,
• (Not looking nice but better then starting in the cold winter (-6.8° under mean) of 1970).
• Sample Serial out put of around one sec 59:

55 Second, 200 ms = 1

56 Second, 100 ms = 0

57 Second, 100 ms = 0

58 Second, 200 ms = 1

59 Second, No pulse = New Minute. Reading time and calculate the DCF array the next minute.

EZ Date and Time: Mittwoch, 26-Feb-2020 17:22:59 CET

Unix Timestamp: 1582737779

Unix Time + TZ +120 Timestamp: 1582741499

0-00000000000000-000101-00100100-1110100-011001-110-01000-000001001

0 Second, 100 ms = 0

1 Second, 100 ms = 0

2 Second, 100 ms = 0

3 Second, 100 ms = 0

• For live and historical DCF reference: https://www.dcf77logs.de/live
• Custom config:
• Timezone Austria; //A Name for Your Time Zone
• #define WIFI_SSID "Your SSDI"
• #define WIFI_PASS "Your WiFi Pass"
• #define OTA_NAME "Device OTA Name" // ESP01S DCF77 Test
• #define OTA_PASS "Device OTA Pass"
• #define LedPin 2 // Using the LED pin as DCF output. Define other pin if DCF using other output pin
• Austria.setPosix("CET-1CEST,M3.5.0,M10.5.0/3"); // Posix for Your Time Zone
• Austria.setDefault(); // Setting Your time Zone as default
• setInterval(1800); // NTP update interval
• setServer("ntp.se"); // Your NTP Serverpool
• Code its partly based on the Swiss code at:

https://www.changpuak.ch/electronics/Arduino-DCF77.php

//////////////////////////////////////////////////////////////

ARDUINO/Genuino (UNO) Test/Demo Sketch for Low Frequency

ASK Synthesizer Software Version 2.4,

24.04.2017, Alexander C. Frank

//////////////////////////////////////////////////////////////

• Witch contain traces of German and Italian :)
• All mods and adds are Copyright 2020 Mattias Westerberg and are free for private use only.
• And WITHOUT ANY WARRANTY and on your own risk !!!
• Alexander have made a very nice looking DCF77 Transmitter that using a SiT8208AC for
• transmitting and keying DCF77.
• In My AVR-DCF-Transmitter i using a 16 MHz ATmega328P for transmitting the keyed DCF77.
• Andreas Spiess have a working DCF77 Transmitter for ESP32 at:
• https://github.com/SensorsIot/DCF77-Transmitter-for-ESP32.
• (With German, Spanish and Italian trace in the Swiss code :))
• Example updating one old weather station with one ESP-01S:
• If the power in the weather station (normally around 3 volt) its in working range connect GND and VSS,
• if not putt one Step-Down / Buck Converter or LDO between.
• Find the data out pin from the DCF module or IC. Cut the cable or PCB trace.
• Connect the GPIO2 to the data pin on the MCU side.
• If having a module you can demounting it and using it for other things / experiments.
• Most clocks needs 2 sets of correct data for sinking the clock and its normally waiting for the
• minute sync (second 59) before starting decoding data, so after 2 - 3 minutes you have a
• well synced DCF77 clock :))).
• If having one ATmega328P with 16 MHz crystal laying around you can using it as a transmitter
• and don’t need doing hardware mods.
• Just connect GPO2 from your ESP8266 to ATMegas D2 and GND to GND, and your antenna to D3.
• Flash my AVR-DCF-Transmitter on the ATMega and put the antenna near / around your clock.
• One real ESP-01S have 1M flash and all pullups and downs and need only VCC and GND for running your code.
• GPIO2 have pullup (Internal LED and resistor), but must being high on boot.
• Its normally the right polarity and current for connecting to a weather stations MCU with out problems.
• If polarity its wrong only shifting the the commands HIGH and LOW for the 100 and 200 ms pulses.
• Its also have large pads for the flash and make it easy to upgrade the flash if NEEEEEEDED !!
• The original (blue 512K flash) and updated (black 1M flash) don’t have all resistors and need
• some to being attached for working and have smaller pads for the flash if need upgrading the it.
• WARNING !!
• Manny sellers selling the updated ESP-01 version (black 1M flach with out "S") as ESP-01S
• (look on the PCB and counting components). If having problem flashing or getting it running
• you need some resistors attached.
• If you need one GPIO that can being LOW at boot (GPIO 0 and 2 cant = Not booting)
• then use GPIO3 (the normal RXD0) and define UART0 to use alternate pins GPIO13 and GPIO15
• or disable it in your code.