Mini AV Test Box

Current Part:

PIC 16F84A Microcontroller
2x 47uF Capacitors
2x 0.1uF Capacitor
2x 15pF Capacitors
0.01uF Capacitor
20 MHz Crystal
7805 +5v Regulator
555 Timer
SPST Switch
10k Resistor
100k Trimpot
6 pin Header
VGA Connector (DB-15)
Audio Jack (1/8")
9v Connector
Breadboard Wire
Soldering Iron

Parts List Details
           Most of the parts used in this project are passive components, like resistors and capacitors. The active components I'll describe in more detail below as they are what really make the circuit work properly.

PIC 16F84A
           For creating the properly timed VGA output signals we will need a microcontroller. It will run specific software we develope later on in the project, that outputs 800x600 VGA signals displaying a block of Red, Green and Blue on any LCD screen. The 16xx PIC series is used because of its small form factor (16 pins!) and low power requirements.

555 Timer
           We've seen the 555 Timer in the recent DIY 2 Layer PCB’s tutorial. The timer as we will be using it, creates a monostable output signal of +0v and +5v, alternating back and forth at a common frequency. The 100k trimpot seen in the parts list above will allow us to adjust the frequency of the timer.

20 MHz Crystal
           It is crucial that you use this exact crystal oscillator frequency. The 800x600 VGA display signals run perfectly at this frequency and it is also the fastest that the 16F84A PIC can go. These crystals are cheap (usually only $1 or less) so get the right one!

7805 +5v Regulator
           This design will use a power supply of +5v for all active parts, this means we need something to regulate the +9v coming from the battery (we'll use a +9v battery to power this project). The 7805 is good for up to and over 1 amp which is way more than we need, but still a small form factor device.

Wires, Connectors , Switches & Passive Components
           Some standard breadboard wire will be used for connecting parts not directly soldered to the PCB like the connectors and switches. The passive components are all used for specific tasks like DC filtering, pull-up or setting the 555 timer output frequency. If you have questions about the schematic that you see next, ask them in the forums. I'm happy to answer all your questions.