LED Visor, MSP430 (Concept)

This post is the first in a multi-post set: 

• LED Visor, MSP430 (Concept)
• LED Visor, MSP430 (Schematic Capture, Layout)
• LED Visor, MSP430 (Software) 
• LED Visor, MSP430 (Final Build into Visor) 

This project actually came before the LED jacket. It also was an experiment to try and see what the process would be like to work with the MSP430 development system at home. I've developed several professional products for the MSP430, but all of them used big expensive compilers with the pcb layout done by our layout team.

Design

 First off, I decided I wanted to put some LEDs on a hat or visor. This made for a nice, trivial project.

I had a ez430-F2013 which I'd picked up from work . It wasn't quite what we needed at work, however it was just fine for a small home project. If your interested, you can pick one up from digikey for about $20.

ez430-F2013 Programmer & dev board.

I also was interested in trying out two new tools.

• One was a PCB EDA tool, KiCad. While I know that a lot of folks like Eagle,  I wanted something that was open source. After looking at gEDA, I decided I would rater use something a little more integrated.
• I wanted to try out BatchPCB, a service which fabricates custom circuit boards. While the wait times can be long, the price was right. I wanted to see if I could take a circuit idea from schematic capture, to layout, to reality. 

For my PCB I need to :

• Provide a power source (e.g. power regulation)
• Provide a circuit for driving the LEDs.
• Provide a way to connect up the ez430 development board.
• Provide a way to control the LEDs.

After some browsing around on digikey, I found the CAT4008 LED driver. It was a nice, low cost, simple to use LED driver so I picked it.

The TI MSP430F2013 can run from 1.8V to 3.6V. For this project, I decided I wanted a 3.5V regulator. After some looking, I picked a small 3.5V 600mA regulator.

I drew up a circuit by hand in my lab notebook, using the reference information in the datasheets for parts I'd selected.

Notebook pre-plan for circuit.

Next: PCB Schematic Capture and Layout.