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

chowfookcheong.blogspot.com

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?