Here is a programmable timer project by Victor. It’s PIC18F4550 based and uses a DS1307 real time clock chip to keep time. A small 12 volt relay acts as the switch. [via]
This project, like others before, has started out of need: our 30+ year old mechanical timer for the central heater of the house has finally given it up. It would have been faster and cheaper to get a replacement from the local hardware store, but I decided to learn something new and I set out to create a digital version of it.
Programmable timer switch – [Link]
An Arduino-based clock with 180 RGB LEDs. The LEDs are driven via 12 TLC5925 1- channel constant-current addressable drivers – [via]
Its built on doublesided copper clad board using Toner transfer method. The routes aren’t smaller than 0.44mm and all vias are made for 0.8mm drilling (truly DIY). Just around 5 vias are under a component and 7 segment displays have singnals only from bottom side (for easy soldering)
- 180 RGB LEDs driven by TLC5925 constant current LED drivers
- each LED addressed separately (12x TLC5925 with 16 outputs each)
- each colour adressed individually
- 4x 7 segment LED display
- Atmega328P as MCU
- DS1307 real time clock
- Photoresistor (for adjusting brightness)
- And DHT11 for temperature and humidity
- Backup battery for clock
- 5V DC (eg USB)
Clock with 180 RGB LEDs on home-etched circuit board – [Link]
The goal of this project is to construct a simple 0-9999 seconds count down timer with an alarm and a display. The time is set through two tact switches and the count down seconds are displayed on a 4-digit seven segment LED display. The project uses PIC12F683 microcontroller for all I/O and timing operations and MAX7219 IC for driving the seven segment LED module. The time out condition is indicated by an audible alarm from a buzzer.
0-9999 seconds count down timer using PIC12F683 microcontroller – [Link]
Ishan Karve writes:
I have made a 16×8 led word clock, a rectangular one. Break from square or almost square ones. This one is a complete modular design and can be scaled up or down in size / complexity according to ones need. The whole design and requisite files are in open domain and the project has also some good 3d pcb renders. The main clock controller is arduino-like and is again scalable.
The LED panel is composed of 8 individual panels of 4×4 LEDs. Each group of 4 such panels will be controlled by a MAX7219. Here are the schematics and board layouts of the 4×4 LED board and LED driver … They are on the way to a fab house….In the meantime I shall do 3D render of my project. Schematics & PCB designed using Eagle CAD 6.2.0 Lite Running on Linux Box.
16×8 LED Word Clock – [Link]
Haris Andrianakis writes:
After some modifications on my UV exposure box (scanner) for better UV expose, i desided that a better pcb must me designed for switch timer. The old one had over drilled holes and it was designed and built on my very fist steps. Also the high voltage side from the low voltage wasn’t seperated as it needed to be safe.
So i redesigned it in a more compact and easier to use pcb. The firmware has been also updated and now you can program the timmer by using the two buttons. The time is calculated by timer interrupt triggering using a 32.768KHz RTC Crystal with better accuracy. The display update also has been changed from static to dynamic.
PCB Exposure Switch Timer V2.0 – [Link]
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]