Arduino. PinMapping168. Some Caveats: ** Caveat #1 : The reason this trick works is that, unlike most Arduinos, the Lilypad Arduino is clocked by the ATMEGA's built-in oscillator instead of by an additional crystal oscillator circuit. This lack of additional oscillator circuitry makes wiring up the circuitry a lot simpler, but as a result the chip runs slower (8MHz instead of 16MHz) and its timing is not as accurate. The lilypad bootloader knows how to compensate for this speed difference to make sure all of your delays and baud-rates and other time-sensitive functions work correctly, but the fact remains that the chip will perform slower.
This is not a big deal unless your application needs very accurate timing or needs to perform tasks very quickly. If you do need your Arduino to run at the proper 16MHz speed, use two 22pf cermamic capacitors and an Abracon ABL-16.000MHZ-B2 crystal oscillator, and connect them as shown in the figure above. Ice Tube VFD Clock - How it works. Www.wulfden.org/downloads/manuals/RBBA_Instructions_04.pdf. Perfboard Hackduino (Arduino-compatible circuit) Make an accurate Arduino clock using only one wire - NO external hardware needed! How to make an Arduino clock - without using external oscillators or clock chips: (more of my projects on our research website - click the arduino logo top of home page) You will need: An Arduino board (just about any flavor will work fine) and software 1 LED 1 Jumper Wire (Wiring Example Updated Below...) I'm an Electrical Engineer of 20+ years and just discovered the Arduino platform a few months ago.
Needless to say I fell in love with it and am now hooked on projects. How to generate the clock pulses in a unique but accurate manner though? I decided to try the PWM analog output wired directly to the interrupt pin 2 and it worked great! The finished gift will have Eagle CAD custom PCB's for the power supply and logic, housed in a plexiglass enclosure. Simple Arduino wiring diagram and demo code to make your own clock using this method. Code and links below... 555 Timer Oscillator Circuit (if you wish to try this method)