This project is a circuit board for making a wrist watch size version of my minidot clock:
with a few more functions more applicable to a portable device. A lot of help and suggestions came from ians 01/\/atch binary watch:
Eaglecad schematic and PCB are available below from the original design, and an updated version with a few corrections is also included. The project is aimed to more experienced electronics hobbyiests as it involves small SMD components, and special programming methods. I'll be going through some of the problems and solutions that arose from making this device. This will hopefully help anyone else attempting to make a small microcontroller device. It might get a bit wordy, if you want action in a hurry....just download the project files and build.
Battery and case construction will be handled in another instructable. This one is just for the board itself.
- microdotfw.zip ...the sourcecode for the Soureboost compiler, includes a .HEX file
- microdotv1.zip ...the original PCB, with a couple of mistakes as mentioned in the text regarding missing resistors
- microdot2.zip ...a slightly modified PCB design, with all the proper components. Note I haven't tested this PCB, but it isn't too different from the original. The software should work on both.
Update 3 August 2007!:
From my other two instructables:
The holoclock - http://www.instructables.com/id/E11GKKELKAEZ7BFZAK/
Charliplexing tutorial - http://www.instructables.com/id/ERHG974F1ZM4KIR/
I've updated the microdot code to incoorporate cross fading between patterns and some better battery management. See attached file "microdot with crossfade and autotimeout.zip" below.
Step 1: The idea
Having done the mini-dotclock I wanted to do a much smaller design. This was mocked up in Eaglecad and visualised in Povray using the Eagle3d user language program for Eaglecad. See ians \/atch project for more details.
This pic sort of set the basic scene, and by printing out the board layout and pasting onto little pieces of paper I could start to visualise the final design. One thing obviously missing from this early design was a way to set the time.....so I thought,and thought.
Then I added SMD switches for input which can be seen in the intro picture.