Nuts and Volts - February 2012

location D10. Solder and snip the leads.

• Insert the two 10-pin straight female headers from the top of the board, and solder the pins in place on the bottom of the board. In order to make sure the two headers are correctly aligned, you can use your completed LED display board as follows: • Place the LED display board upside-down on a flat surface.

• Insert the two straight female headers onto the pins of the LED board’s male headers.

• Inspect the board carefully for accidental solder connections or other problems.

TESTING THE STRIPBOARD “SANDWICH”

We’re just about out of space this month, but we still have room for a quick test of the complete stripboard sandwich. A simple testing program (LED27test ABC.bas) is available with the downloads. We can’t discuss how it works this time, but you can still use it to test your project.

Figure 10 is a photo of my LED-2x7 installed on a breadboard and running the test program. (The power and ground connections are not visible because they are behind the LED-2x7.) As you can see, I’m using the AxMate-FT programming adapter to power and program the board. Of course, you can set up your breadboard circuit using any adapter you have on hand. When you download and run LED27testABC.bas, you should see a repetitively changing pattern that has the following characteristics: • At any given time, only one segment is lit on each digit.

Next time, we’ll get into the software details of untangling the “illogical” I/O connections to the LED display segments. However, there are quite a few hints embedded in our little test program, so you may want to tackle that task on your own. We’ll also experiment with IR input to the LED-2x7 board, as well as temperature measurement. Even if you decide not to construct the LED-2x7 board, you will be able to use simple breadboard circuits for our experiments next time.