Creating a circuit board to fit a specific enclosure can be a challenge even though vendors are often providing drawings with the recommended board dimensions.  Many enclosures use boards shaped like the one shown here — basically a cross shape with rounded corners.  Even with dimensions given, laying out a board this shape in Eagle or another CAD program is tedious and subject to errors because of the many calculations that must be made.

To simplify the process, I developed the Eagle Board Layout Assistant using Visual Basic 6, which will run on Windows computers.  Three x dimensions, three y dimensions, the mounting hole diameter and the inside corner radius must be entered in the simplest case and the program creates a script file that may be run in Eagle to create the board layout.  The script may be run in a new blank board or may be run inside the library editor to create a new component that can be used again in the future.

Download Eagle Board Layout Assistant, revision 1

SMT Prototype Board Compendium

Many chips are only available in surface mount (SMT) packages and they are getting ever smaller as the drive towards miniaturization continues.  This makes it tough to experiment with the parts on a bread board.  Fortunately, they are a variety of adapter boards that make experimenting with these devices easier.  One of the challenges is finding a suitable board when you find a chip you want to use available in only some tiny package.  This article is meant to be a reference to find different boards.  As adapters or proto-boards come and go, this reference will evolve.

I've included a tiny fraction of the available boards here - I know there are many others.  I need your help to list different boards.  Please send me information about boards you may find.  Also, to continue this effort, I have to know that people are looking at the information and using it; your comments are not only welcome but are essential to continuing this project!

I saw reference to the Color Maximite single board computer in Circuit Cellar Magazine and am impressed enough to share it here.  Like desktop computers of old, it has a Basic interpreter built in, along with monitor and keyboard support and an SD card " floppy drive."  The unique feature is that it supports ubiquitous Arduino shields along with I2C, SPI and a number of port pins.  Not bad for $50..  Check out Circuit Gizmos web page for some interesting products.  The description below is from their website.

CGCOLORMAX2  - Color Maximite

Color Maximite-type computer/controller with serial circuit support and prototype area

$49.99 US dollar     Product #CGCOLORMAX2 In stock

CircuitGizmos Color Maximite

People often despair at me for constantly raving on about how great Microchip PIC microcontrollers are, and how much better than everyone else they are.

While I completely agree that each microcontroller has its place in the world, I have yet to find a situation where Microchip don't have a microcontroller which is at least as good as the competition at fulfilling a role, whilst at the same time providing just so much more in the mix as well.

So, I thought I would look at the Arduino UNO's heart and soul, the ATMega328P - a chip that everyone on the Arduino forums thinks is the best micrcontroller, and the only microcontroller you will ever need. I figured I would try and find other microcontrollers from other manufacturers that matched it as closely as possible and compare them - in an objective manner.

After much hunting through product lists from both Microchip and TI I found two suitable matches. The basic criteria:

1. Must be in a DIP package.
2. Must try and at least match the Flash and RAM specifications. If possible.

I found an admirable match in the Microchip PIC18 range, with the PIC18F25K80 chip - same package as the ATMega328P, with pretty much the same spec. However, TI failed me miserably. So, I have the best I could find in a DIP package from them - the MSP430G2533. A pretty poor comparison that chip, but all I could find.

So, I looked at the basic facilities that each chip provides, and scoring each one on a comparison with the two other chips.

This is a continuation of Using the HLVD Module in Swordfish Basic.  Here's a detailed look at using the HLVD module for detecting a low battery as I touched on in the previous artile. 

A lot of variables go into the viability of this technique including the battery chemistry, the number of cells, the current drawn from the cells and whether the load is steady or intermittent.  Conclusions based on these NiCAD batteries will generally apply to NiMD batteries as well.  Li-Ion and Li-PO batteries have some very specific requirements for charging, discharging and maximum and minimum voltage and won't be covered here.