Jürgen Beisert writes:
I like the handy DCF77 signal. In this project no clock should use it, instead the computers in my home network should be served by a precise time reference. Due to the fact most other interfaces are no longer available on modern computers, it uses the USB to forward the prepared DCF77 signal to the host.
DCF77 to USB converter - [Link]
Bill shows the world’s smallest atomic clock and then describes how the first one made in the 1950s worked. He describes in detail the use of cesium vapor to create a feedback or control loop to control a quartz oscillator. He highlights the importance of atomic team by describing briefly how a GPS receiver uses four satellites to find its position. You can learn more about atomic clocks and the GPS system in the EngineerGuy team’s new book Eight Amazing Engineering Stories http://www.engineerguy.com/elements
How an atomic clock works, and its use in the global positioning system (GPS) - [Link]
Well, our meetings take place on wednesdays at 10:30 (sharp). A radio controlled clock is used to determine whether you are late (and must bring a cake next time) or not. Unfortunately the identical radio controlled clock in my office always shows a different time
After baking a lot of cakes, I thought about synchronising these disreputable clocks …
Homebrew DCF-77 Signal Generator - [Link]
Simpleclock is an easy to assemble attractive 4-digit 7-segment LED display clock with temperature and alarm function. It is available in three display colors: Red, Blue and White.
It comes as a kit of through-the-hole parts and can be soldered by any person with basic soldering experience. An attractive acrylic stand is included.
Simpleclock: An LCD clock kit suitable for beginners with open source Arduino firmware - [Link]
The DS3231M breakout board is a compact breakout board for the new DS3231M high precision real time clock chip. With it, you can add timekeeping and alarm functionality to any Arduino (or other microcontroller that supports the I2C/TWI protocol).
The board comes with an onboard CR1220 backup battery (keeps time when main power is disconnected). All pins on the chip are broken out, allowing you to use extra features such as 1Hz and 32kHz square wave output, interrupt on alarm and reset.
DS3231M Real Time Clock Breakout - [Link]
Haris Andrianakis writes:
This is a project i designed a year ago but never built, because of not enough spare time. This month i found some free time so i started building it and i send the pcb layout for manufacturing.
All started when i received some IV-11 vfd tubes from an ebay seller i ordered from and i started testing and prototyping by first trying to simple light up the VFD tube.
A VFD tube works like a 7-segment led display with some small differences.
A) The Filaments. The Filaments exists to power the tube. We have to supply these two pins with 1.2Volt and nothing more (polarity doesn’t matter).
B) The Grid. The Grid is like the common anode of a 7-Segment LED display. So the Grid has to be pushed high at 60Volt (in these tubes) in order the segments to be able to light up.
C) The Segments. The Segments light’s up simple by pushing them high at 60Volt.
IV-11 VFD Tube Clock Final Design - [Link]
The Binary Burst clock shows the time with LEDs:
The clock uses 3 LEDs on each spire to count up to 5 in binary. The hours are displayed by the middle LED in RED (Its a Red/Blue bicolor, the others are just blue). Video, and links to the board and code repository are included in the post. Check out a demonstration video below. There’s also a time-lapse soldering video of build. [via]
Binary Burst clock ticks away the time with LEDs - [Link]
This device is a countdown timer specially designed for PCB exposure box.You can set how many minutes will be on UV light device , store this time in PIC’s EEPROM . Pressing start button lights are on until preset time ends. When lights are off an audible signal is heard. Microcontroller used is Microchip’s PIC 16F877. I used Mikroelektronika Mikropascal compiler to program the chip. Delay time 1-255 minutes.
Count down timer for UV PCB exposure boxes - [Link]
This is a good looking and practical device that can be useful in many areas where countdown timer is needed. This project is based on the PIC16F84A microcontroller. The time range can be adjusted between 1 and 999 seconds. This project has 3 buttons and one of them is named Set Button. In order to regulate the seconds up or down on the display you should press the Set button while pressing the button on the left or the right hand side. The author of this project is @Pedja089. More photos on Facebook Fan Page.
Timer from 1 to 999s with PIC16F84A - [Link]
Using a better antenna to improve DCF77 reception on long distances
We are in the prototyping phase of building a Nixie clock using 1N-14 Nixie tubes. The clock is designed around a PIC16F886 MCU, 74141N BCD decoder/driver and CNY74 optocouplers using common circuit topology. High DC voltage (+ 180VDC ) is generated using MAX1771 step-up switching regulator, which is quite efficient (if you use appropriate components).
Our clock will have some nice features:
- Compact design
- Manual time configuration
- DCF77 time synchronization
- Sync success indicator
- HV shutdown during sync (to reduce noise received by DCF module)
- Super-capacitor time backup
- Thermal protection
- ICSP connector etc.
When clock is complete we will release it as open source-hardware here at Electronics-Lab.com
We decided to use DCF77 signal as time reference for two main reasons, it’s quite easy to receive it and it’s very accurate for the reason that carrier signal is generated from atomic clocks.
But, what about receiving and decoding DCF77 signal? Read the rest of this entry »