Monday, May 18, 2009

Alarm Clock Board Built!

Last night, I finished the board layout in EAGLE and got to work making it:
  • Turned off layers in EAGLE except layer 1 and pads, and printed to a PDF,
  • Rasterized PDF in Photoshop at 1200dpi and processed into a black+white image (right),
  • Laser printed onto an L.L. Bean catalog page, with the print output set to "transparency,"
  • Ironed onto 2.5" x 2.2" single-sided copper clad,
  • Fixed gaps with etch-resist pen,
  • Rubbed off paper and etched in ferric chloride for 15 minutes (though I'll use use the HCL and peroxide method in the future),
  • Rubbed away ink with acetone,
  • Tested trace continuity and scraped away tiny bridges with a knife,
  • Drilled out all holes (1mm bit),
  • Populated with parts and soldered it up,
  • Pressed chips into sockets,
  • Hooked up LCD, jog/shuttle, a button and LED.
It behaved exactly like it did on the breadboard! Now I can focus on the right button/LED combo and casing, redoing the relay board, and tightening up the program.

This is my first from-scratch Arduino-compatible board-- sure to be the first of many...:)


  1. What exactly does it do? If its what I think it is, then it is fantastic! I'm really interested in what the phone cord is for.

  2. Realized, that what looks like a phone chord is most likely a creative way to power everything. The jog is very impressive. Im wondering how accurate it is. Most alarm clocks lose anywhere from a few milliseconds to entire seconds everyday.

  3. Finding this comment late, sorry! It uses a DS1307 real time clock chip to keep time, so even when the board is powered down, the clock still keeps time, powered independently from the CR2032 battery.

    The 4-conductor phone cord goes to a secondary power box with a regulated 5V power supply and two relays: the cord has +5V, GND, and relay1 and relay2 control. The relays control the output of a second power source-- ~24VAC.

  4. good stuff, how accurate are you finding the DS1307 to be, and would you recommend a different chip as a real time clock after you have had experience with this one?