DBClock

Features

NTP Sync
LED lightning, dimmable
Stand
12V
Webinterface for configuration
Daylight Saving

Bahnhofsuhr-DB

Dark blue metal case, acrylic glass panes, dial white,with black hour and minute markers, red hole second hand, red DB logo unlit.

Condition: used, in new design, the sale is in the current condition as a decorative object, a function can not be guaranteed, rust spots, paint chips and scratches in the glass and paint are part of the character. The holder is not included in the delivery. The article picture is an exemplary representation.

Dimensions: 60 cm diameter Weight: approx. 30 kg

Shipping is by freight forwarding on one-way pallet (free curbside). Disposal of the pallet is done by the customer.

In my clock, BU 190t S230 the clock-drives were used.

BU 190t S230

A complete manual for the drive can be found on the manufacturers website: Uhrwerk-BU-190-230-Installation.pdf

POWER THE DRIVE

I got the BU 190t S230 version which needs 230v. After a teardown, a small rectifier is found so that the drive uses a lower voltage for the motors and logic. After further investigation on the transformers, the drive is internally operated with 12 V. So if you solder some wires directly to the rectifier and run it with a 12 V power supply, the drive works fine. It also uses its own crystal, so no need for a stable 60Hz sync from the mains.

SET THE TIME USING AN ARDUINO

In general it is simple to set the clock using a serial connection to the IN connector of the drive. The connector is a RJ12 jack it is connected to the Arduino using the following pins.

Arduino	BU 190t	RJ12 pin
TX	TTL IN (RxD)	1
GND	GND	2

The following Arduino code function sends the current time to the drive. After running the code, the clockdrive syncs up. This takes up the 6 minutes.

void send_time_to_clock(const uint8_t _h, const uint8_t _m, const uint8_t _s, bool _signal_ok = true);

void setup(){
  // NOTE THE SPEICAL SERIAL INIT ACCORDING THE DRIVES DATASHEET
  Serial.begin(9600,SERIAL_7E1);
}


void loop(){

send_time_to_clock(13,14,15)
//SEND THE CURRENT TIME EACH SECOND
// USE A DEDICATED TIMER FOR THIS
delay(1000); 
}
void send_time_to_clock(const uint8_t _h, const uint8_t _m, const uint8_t _s, bool _signal_ok = true){
  const uint8_t sec = max(_s, 60);
  String s = String(sec);
  if(sec<10){
    s="0"+s;
  }

  const uint8_t min = max(_m, 60);
  String m = String(min);
  if(min<10){
    m="0"+m;
  }

  const uint8_t hour = max(_h, 24);
  String h = String(hour);
  if(hour<10){
    h="0"+h;
  }

  String signok = "M";
  if(_signal_ok){
    signok = "A";
  }
  // USE WITH IN SETUP Serial.begin(9600,SERIAL_7E1);
  //DATE SET TO 10.10.2000 => NOT NEEDED HERE
  Serial.print("O" + signok + "L010100F"+ h + m + s +"\r");
}

In my case i used a Arduino Mega, with more than one hardware serial interface. The desing is using Serial2 for the clock drive and Serial to communicate with the PC or ESP8266 for NTP Sync. By using a RTC like the DS3231 in combination with the ESP8266 for NTP sync, you get a very stable self syncing clock! The the src directory for the Arduino and ESP866 sources.

LED

The old lamp was replaced with a neutral-white 12B led strip with 144 LEDs/m. Using a mosfet connected to the Arduino PWM GPIO Pin 8, so it is possible to control the strip using software. The current implementation, allows fade up/down on predefined times, on/off from 0-100%.

BUTTON

A pushbutton from GND to Arduino GPIO 2 can be connected to set the LED intensity modes manually.

FINAL PINOUT

Arduino	BU 190t RJ12 pin	DS3131	PUSHBUTTON PIN	MOSFET PIN	ESP8266
VIN	+ pin on fullbridge
TX	TTL IN (RxD) 1
GND	GND 2	GND	1	GND	GND
2			2
8				SIG
5V		VCC		VCC	VIN
RX					TX
SDA		SDA
SCL		SCL

Stand

A clock stand/holder was not included, so a simple millable (or 3d printable ABS 100% infill) was designed. The bottom holes are designed to be mounted on 30x30 n-nut profiles. The files can be found in the src/3d_print/clock_mount directory.

Four M8x30 with lock nuts were used to attach the clock to the milled stand.

NOTE The clock weighs about 30 kg, so the stand should be durable...

RBEGamer/DBClock