Thursday, November 24, 2011

Starting your First Lunetta Module: Tip No. 1

Diagrams, schematics, datasheets are important tools to get you started for sure.  But nothing beats a simple photo in regards to construction methods.  If I showed you a pic of a finished module, the message may get lost in a sea of wire.  So for simplicity's sake, let's have a look at this photo.

I first figure out how many ics I can comfortably place on the size of perf I have.  Then I use sockets in place of the actual cmos chips.  Why, you ask?  This prevents the chips from being fried due to excessive soldering, for one.  Secondly, if something goes wrong with an ic, you can just pop in a new one.

First, I connect a 0.1uF cap as close to the power pin as possible and ground.  That's going to ensure that all our chips have a reserve of power.

Next, I use my datasheets to figure where my power and ground pins are.  I use jumpers to tie the power pins to the power bus of the perf board and all the ground connections are wired to the ground bus.

Note: While many of the ics will share similar pinouts, there can be exceptions.  Some ics use 14 pins and some use 16 so I use 16 pin sockets to take care of both sizes.

The next steps are to place pulldown resistors (100k) on the inputs of each ic.  I use a simple drawing next to me to make sure I know what each ic is which when I'm working on my board.  One leg of the resistor goes to the pin and the other leg goes to ground.

After the resistors are in place, I use green wire for the inputs and black for the outs and connect them to their respective spots.

Before I wire up the wires to the jacks, which are already mounted on the panel, I run a long black and red pair of wires that are attached to the positive and negative rails of my perfboard.  These long wires are connected to the Main Power Board, which is a board that supplies power to all the modules.





2 comments:

  1. Great tips !!! Thank you very much. (^_^)

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    1. Glad to be of help. Even though I haven't updated in a while, these steps represent the core process. Lots of beeps and bloops await!

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