Simon Part 5: Parts, prototype, PCB assembly.

Based on the schematic I used I set about gathering the parts I will need to construct the final game.

Shopping List

Buttons & Switches

4 x 28mm LED illuminated arcade buttons (ebay)
1x 20mm power on / off switch (RS components)

Components

3 x 220ohm resistors
1 x 120ohm resistor
1 x 560ohm resistor
1 x 10kohm resistor

2 x 100nF capasitors
1 x 0.33µF capasitor

1 x 78L33 3.3v voltage regulator

1 x 8pin IC Socket.
1 x LPC810 micro controller

1 x battery holder for 3x AA
1 x piezo buzzer
16 x 2.5 mm spade connectors (for connection to buttons)
2 x 5mm spade connectors. (for connection to power switch)

Prototype:

The first thing I did was lay it all out on a bread board to test it. (ok I admit it, i lost the photo of my prototype but it was a lot like this one).

Assembling the PCB

Putting everything together was a little slower than I expected. The components went on to the board in a few minutes but cutting, stripping, tinning and then soldering in all of the wires for the buttons / LED, etc was time consuming. I should have put a ribbon connector socket on the board. Not doing this was a bad decision.

Anyone with eagle eyes may spot a couple of additional transistors on that board. When I actually assembled the board with the arcade buttons, the red and yellow buttons were not bright enough, despite being perfect when I tested with loose LED on the breadboard. I decided to do a quick hack and use an NPN transistor (547 b) as a switch so I could route the full 4.5 volts to the red and yellow LEDs to brighten them up a bit.

To make that adaption I did the following so I could avoid any major changes.

LED + direct to 4.5v / power.
LED - to Transistor Emitter (pin3)
Originally intended + LED position on the board to BASE (pin2)
Originally intended - LED position on the board from Collector (pin1)

I maybe did not need to make that change but decided it would be a better end result.

a bored programmer