The Daily Duino

Quick update before I zonk out…  Yesterday I setup an account for Pachube and spent all night getting familiar with how it works. Pachube describes itself as a service that enables you to connect, tag and share real time sensor data from objects, devices, buildings and environments around the world. The key aim is to facilitate interaction between remote environments, both physical and virtual.

It also works with Arduino and Processing… hrmmmmm…..

The graphs will continue to update as they receive more data from the sensors.  It will be interesting to watch and compare the differences in the two graphs.  More to come soon!

–Morgellon OUT!!

Television! Teacher, mother, secret lover. –Homer J. Simpson

Having only discovered the duino recently, I’m constantly searching for applications that push the limits of what can be done with the device. There have been several sketches posted that will output composite black and white video to your TV with a very simple circuit, but the most interesting of these to me is the Arduino Pong code by Alastair Parker. What I’ve done is strip the code down to just the intro screen in order to simplify the idea and get my mind wrapped around it. Check out the following schematic, code and resulting output.

Download the code.

Arduino Composite Video Schematic

To change the on-screen text, grab a sheet of graph paper, create a rectangle that is 38 units wide and 14 units tall, and mark the pixels you would like to turn on. After that, it’s simply a matter of changing the “setPixel(x,y)” lines in the code. Have fun and as Homer says: Let us all bask in television’s warm glowing warming glow.

Composite Output Result

The circuit on breadboard

To do a wired serial conection you need 3 wires, rx, tx, ground.  Don’t forget the ground, that had me all confused and frustrated.  The tx (transmit) and rx (recieve) wires need to be crossed.

I wrote a simple sketch that starts at 0, outputs that value, increments by 1, outputs that value and so on.  This sketch will be used for all of my serial communication between Arduino posts. code

LCD output

So I get my sketches running, one outputting that information and the second reading it and displaying it to an LCD.

Then I wire everything up.

This allows tx and rx between the 2 Arduino’s dont forget the common ground.  With wireless you do not have to have that common ground, my next 2 posts will be on such things.

Download the sketches I used

I currently own and have used 2 16×2 LCD’s with my Arduino projects.  One from Modern Device and one from Sparkfun.  Both are very easy to use with the Arduino, as they have an added on board that handles all the communication and all you have to do is send 3 wires, power, ground and data to the LCD.  I wanted to give a short rundown on the 2 LCD’s and maybe help you choose which one to get.

Cost:
Modern Device: $20
Sparkfun: $24.95
Winner: Modern Device

Colors:
Modern Device: White on Blue
Sparkfun: Red on Black, Black on Green, White on Black, Yellow on Blue
Winner: Sparkfun

Hardware:
Modern Device: You have to put the thing together, it has a test button and a demo button, trimpot for contrast, you can use the same power supply for running the LCD driver and the backlight or you can seperate things out Also the LCD117 is bigger than the sparkfun board, but can be removed from the LCD and connected to different inputs for different LCD’s
Sparkfun: It comes preassembled which is faster but has less hardware features.
Winner: Tie The Modern Device kit can be preassembled but it adds to the cost.

Modern Device Side

Sparkfun Side

Modern Device Back

Sparkfun Back

Software:
Modern Device: At the bottom of the page on the LCD there is detailed examples of how to use the code and an Arduino sketch to upload and demo the board.  It allows custom characters and even has a windows utility to create them. You can use the serial port on your arduino or you can use the SoftwareSerial library
Sparkfun: No example code, you have to search the internet for such things or keep reading this blog as I am going to post on it in a few days. You can also use the serial port or SoftwareSerial
Winner: Modern Device

Support:
Modern Device: Has their own forum that is managed by the developer (its a one man shop).  He also does support via email but would rather use the forum.  He has a limited amount of items in his store and he designed most of them, so its a knowledgable place
Sparkfun: They have their own forum but are trying to support many more products (19 pages of results for arduino LCD). They also have ~10 16×2 LCD’s and over 20 different LCD’s for sale
Winner: Modern Device

Both sites have great LCD’s, for the Arduino user though, Modern Device is going to make you happier.

Overall Winner: Modern Device

Several of my favorite Arduino/Freeduino stores have sent us in some giveaways for the con.  We are not sure how we are going to be giving things out, as most are kits, I think we will be giving them out during our talk and during the tutorials going on during the day.  Maybe get a few teams together during the talk and give them each a board to put together and do a project off of.  Then give more coolness away for the team that makes the coolest stuff, I guess I need to bring a big box of parts.

Paul from Modern Device sent in 3 rBBB’s, 2 P4 RS232 to TTL Serial Adapter Kits, 2 LCD117 Serial LCD Boards, 2 16×2 blue LCD’s and a Serial Cable.

Lady Ada from Adafruit Industries gave us a Motor Shield and a Wav Shield.

NKC Electronics sent in 3 x Freeduino USB kits and 2 x Freeduino serial kits.

I owe each of these folks something and I am working on it.  Please check out their stores for the coolness.

First off, I enjoy showing my wife thing that I build or write.  She enjoys showing me her projects, but as she is a photographer, her stuff is usually cooler looking.  Fancy cron jobs and database queries just don’t have the bling of an underwater naked woman in an artful pose.

Since I started playing with Arduino’s, my wife knows that her kitchen table will be full of wires and little electronics that our kid doesn’t need to pull off the table.  Little LED’s that blink or some serial output to a computer are cool, but not so impressive.  But serial output to an LCD, a cool blue LCD, now things start to get interesting.

RFID Reader

Those are pictures of a RFID reader that I built the other day.  My 1.5 year old daughter thinks its the coolest thing.  Not only does an LED light up when a tag is read, but it has that fancy LCD.  Good design should be usable by little kids.  She can work the remote to our Mac’s, she can work an iPod, and now she can work my RFID reader.

RFID Reader LCD

If she knew how to solder, she could probably put one of these LCD’s together.  I am using 2 LCD’s from Modern Device and their Serial LCD Board to drive them.  Its as easy as adding a second serial output to your projects to add in an LCD.

There are a few other things you have to send on that serial connection and they are well documented at the bottom of the the above link.  There is also a test function on the Serial Board to make sure you hooked everything up properly.  The board will run either LCD, but you have to have different headers installed and a different resistor for the backlight.  No resistor, just a jumper wire for the 16×2 and a 15 ohm for the 20×4.

LCD117 Serial LCD Board

I had some problems with one of my Serial LCD Boards, but it seems to have been a hardware problem, I resoldered everything and it worked.  Paul at Modern Device has a forum set up where he will help you with any problem.  It’s very cool to have a company that sells things at good prices and will help you with their products.

20x4 LCD

Here is some example code to send data to the 16×2 LCD (just like the RFID Reader)

#include <SoftwareSerial.h>

#define rxPin 4
// rxPin is immaterial – not used – just make this an unused Arduino pin number
//the txPin is an unused digital pin, you can use analog pins for digital pins
#define txPin 14 // pin 14 is analog pin 0, on a BBB just use a servo cable

SoftwareSerial mySerial =  SoftwareSerial(rxPin, txPin);

void setup(){

pinMode(txPin, OUTPUT);
mySerial.begin(9600);    // 9600 baud is chip comm speed

mySerial.print(”?G216″); // set display geometry,  2 x 16 characters in this case
delay(100);               // pause to allow LCD EEPROM to program

mySerial.print(”?Bff”);  // set backlight to 40 hex
delay(100);              // pause to allow LCD EEPROM to program

mySerial.print(”?s6″);   // set tabs to six spaces
delay(1000);              // pause to allow LCD EEPROM to program

}

void loop(){

mySerial.print(”?c0″);          // turn cursor off
delay(300);                //without the delay, the LCD will crash

mySerial.print(”?f”);                   // clear the LCD
delay(100);
delay(3000);

mySerial.print(”?x00?y0″);              // cursor to first character of line 0

mySerial.print(”LCD117 test”);

delay(3000);

mySerial.print(”?x00?y1″);          // move cursor to beginning of line 1
mySerial.print(”moderndevice.com”);     // crass commercial message

delay(6000);                          // pause three secs to admire

mySerial.print(”?f”);                   // clear the LCD

mySerial.print(”?x00?y0″);          // move cursor to beginning of line 0

mySerial.print(” LCD 117 chip by”);         // displys LCD #117 on the screen

mySerial.print(”?x00?y1″);              // cursor to first character of line 1
mySerial.print(” phanderson.com”);

delay(3000);                          // pause three secs to admire

mySerial.print(”?f”);                   // clear the screen

delay(1000);
}