For Kal

The design for the circuit board has been drawn up and is ready for prototyping. Unfortunately, to make the rectangular red LED brighter, I have to use another IC since the signal coming out from one of the ICs are very weak.

Then the bad news came that the vendor could not get my board made in time, which is before the 24th of July. And so, I had to make my own working prototype from scratch. Sigh.

This time, I am using another type of prototyping
board. Although from the top it looks like one of
the normals stripboard, it is not,

The shopkeeper called it the 'donut' board while I
suspect it is a wire-wrapping prototype board. Here
you can see the under the board, there are no strips
but just copper holes. In actual application, you just
solder the components in, then use a wire-wrapping

The advantage over a normal stripboard is that
you can place your components anywhere you
like as you will be making your own connections.
A normal stripboard, you have to follow the rules
which will result in a very bigger prototype board.

Because the components will be soldered onto
the board, I have to check each connections
before I go to the next stage. To desolder a
soldered component not only weakens the
prototype board it is also potential short
circuit waiting to happen.

Just to wire up the 7-segment display, you would
need this much of soldering and wires. Note the
wires I use are very thin. They have to be since
there will be a lot of links and using thicker
wires is just asking for trouble.

Once the LEDs are in and tested to be OK,
its time to put in the remaining components

Which means more soldering. Although you feel
that this is easy, I spend more time bending and
twisting the wires to get them to 'fit' before I
permanently solder them into place.

Finally, its done but since this is a prototype,
the board is a bit wonky and also, it uses a
set of three AAA batteries due the limitation
of the other ICs in there.

I have other ideas to reduce the component count but let's leave it a that for the moment because it would be a case of cost versus power (and money) consumption of the circuit. So, when do you need this?