Enterprise Navigation Lights:Soldering the first board

OK, since today is Friday, and tomorrow is not a working day (for the first time) I decided to solder the first printed circuit board (PCB) to see how well my design is. There are a lot of boards and its not easy since I still do not have a proper solder jig. This is a piece of tool where you insert all the components onto the PCB, clamp it to the jig, where the sponge/soft material will ensure the components to not fall off while you turn it upside down and do your soldering.

OK, this is the board, which is actually,
1 1/8 x 2 1/8 inches (about 4cm x 6cm)

First thing is to solder the 1/8 watt resistors. I chose
the 1/8 watt over the larger conventional 1/4 watt
as I wanted to make it as small as possible but not
too small until I need to use surface mount versions.
In this case, I have to solder them first as they are
the smallest components, not forgetting the diode
as well. You have to solder from the smallest to
the biggest since you're turning the board upside
down. Solder a big component first and all the
smaller components will fall off when you turn it.

This is the first mistake. I should have chosen a
TO-92 design instead of the TIP31A design as I
think the current consumption will not exceed
over 500mA. Anyway, each voltage regulator
will have to have its legs bent this way too.


Next would be the two NPN transistors which is
used as a current switch to the LEDs from the
microprocessor chip.

Then its the IC socket and the pin headers before
I put in the green power connector as it is easily
the 'tallest' component on the PCB.

Once the whole PCB is populated, I can now
concentrate on the SMD resistors under the
PCB. I only used four per board as soldering
them is not easy. You can see how small they
are.

Still can't imagine the size? Here it is again,
on the palm of my hand. At 40 sen, this is
very expensive compared to a normal 3 sen
resistor. So, it is nothing to be sneezed at....
(Yeah, you can read my palm too)

Phew! After minutes of frustrations, it is all done.
I only read the theory on how its done and when
it came to practical, I was lucky not to burn the
whole board since I was applying a lot of heat to
it. A lot of unnecessary heat.


And I have to crimp the cables on one end and
also crimp the connectors to it on the other end.
This is so that I can plug the LEDS in instead of
soldering it since not a lot of people have soldering
irons in the house. If I use the screw connectors
like what I did for the power, the board would
be very big and thus cost more to make.


Finally, the last stage is to program the chip, and
out it into the board. Power it up and it works!
Woo hoo!


This means I am ready to make some boards! But due to budget constraints during component purchasing, I will make them in batches while I get more funding. Right now, I calculated that I should be able to make about six boards minus the cables/LEDs. Let's see how tomorrow fares.

No comments: