October, 2009

I recently bought an Arduino starter kit along with the Ethernet "shield". In addition, I got a uVGA-PICASO-MD1 Graphics Controller chip, which attaches on to the PICASO Universal Base Board. The total price was around 130 Euros. And the goal: To create a device which takes Ethernet input and gives VGA output. The use case would be typical demo or dashboard screens, which need no user interaction, and to avoid the 3GHz/4GB RAM laptop or desktop which usually drive them.

The software installation on Fedora 11, 64 bit was relatively pain less. There are a few steps to follow, and also some special tricks for 64 bit. The gist of it, went something like this:

# Install the RPMs available from Fedora repositories.
yum install java-1.6.0-openjdk avr-gcc avr-binutils avr-libc avr-libc-docs avr-gcc-c++ avrdude rxtx uisp

# Add your personal user to these groups: dialout, uucp, lock
emacs /etc/groups


And that’s that… Thanks Sebastian Tomczak for his blog entry on the same topic. And also thanks to Jonathan Laloz for "The Potter Project", where he provides the NewSoftSerial and Picaso libraries. Without them, I would have struggled a lot more. Thanks to them, I now have a working network server on the Arduino which prints the input text through the VGA chip. Using nc, it be comes a "remote screen".

nc 192.168.2.150 9090
Hello World!![ENTER]


Here’s my program as it looks tonight:

#include <Picaso.h>
#include <NewSoftSerial.h>
#include <Ethernet.h>

//Define the Picaso object
Picaso VGAOut;

// Set MAC, IP, and start server on port.
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
byte ip[] = { 192, 168, 2, 150 };
Server server(9090);

void setup() {
// Initialise the uVGA device, Set the resolution to 640 x 480
VGAOut.Init(); VGAOut.SetResolution(1);

// Init Ethernet shield
Ethernet.begin(mac, ip); server.begin();
}

// Blink some LEDs attached to digital pins 4 and 5
void blinkTwo() {
digitalWrite(4, ON); digitalWrite(5, ON); delay(50);
digitalWrite(4, OFF); digitalWrite(5, OFF); delay(50);
}

void loop() {
// Run the demo once, just to make sure there's something which works.
VGAOut.Demo(); VGAOut.Clear();

// Listen for incoming text over Ethernet.
Client client = server.available();
if (client) {
blinkTwo(); blinkTwo();

int x=10; int y=10;
while (client.connected()) {
if (client.available()) {
digitalWrite(5, LOW);

// Draw character by character from the input stream.
char c[2] = {(char)client.read(), '\0'};
VGAOut.DrawText(x, y, 1, c, VGAOut.GetRGB(255, 255, 255));

delay(30); digitalWrite(5, HIGH); delay(30);

// Wrap the lines. (I guess I can fit a bit more here...)
x++;
if(x > 40) { x = 0; y++; }
if(y > 40) { y = 0; }
}
}
client.stop();
} else {
// If client was connect, turn on the red light.
digitalWrite(4, OFF); digitalWrite(5, ON);
}
delay(5000);
}