You can either use “context.clearRect(0, 0, canvas.width, canvas.height);” Which I found only worked sometimes, and best in desktop version of the browser.

What I did was the width trick (setting the canvas width to itself clears EVERYTHING), and since I had also drawn lines I had to run the beginPath() method like this:


context.fillStyle = "#000";
context.fillRect(0, 0, context.canvas.width, context.canvas.height);
context.canvas.width = context.canvas.width;
context.beginPath();


Creating a rectangle that paints the whole screen was key for mobile. beginPath() will clear all the old paths for you. For some reason it kept leaving the last path I drew even when I was trying to clear the whole thing. Have fun!

I did a little enhancement on the basic turn an LED on/off by giving it a string of char representing morse code and making it blink to that.

Here is the board setup:

How to setup the board:

1. Plug a wire from Pin 5 to the breadboard (red wire in pic above)
2. Continue the circuit by pluggin in a resistor from where Pin 5 connects on the breadboard to the where you wish to insert the LED
3. Connect the side of the LED that DOES NOT have the flat edge to the resistor on the breadboard
4. Plug the flat end on the LED in any row on the breadboard that is not where the other wires are connected
5. Connect a wire from where the flat end of the LED is connected to the Pin labeled “Gnd” (a.k.a. Ground on your Ardunio board) (white wire in pic above)

Here is code to compile and upload to your Ardunio. The morse code is represented by dots and underscores. Read the comments in the code to get a clear understanding of what is going on:

Not the most elegant, but I am a beginner so far. You should now see the LED blink whatever Morse code you write with periods and underscores. Have fun.

1. Sign up for a free account with Twilio. You will get a good amount of free credit to play around with.
2. Install the Twilio Ruby Gem by navigating to your project folder in Terminal and typing:

   
   sudo gem install twiliolib
   
   

3. In your controller (create a new controller if you want), put this chunk of code at the very top. Replace SID, ACCOUNT_TOKEN, and CALLER_ID with what Twilio provides you:

   
   require "twiliolib.rb"
   
   # your Twilio authentication credentials
   ACCOUNT_SID = "put_your_sid_in_parentheses_here"
   ACCOUNT_TOKEN = "put_your_token_in_parentheses_here"
   
   # version of the Twilio REST API to use - do not change
   API_VERSION = '2010-04-01'
   
   # Sandbox phone number
   # or outgoing Caller ID you have purchased through Twilio
   CALLER_ID = "put_your_sandbox_phone_number_here"
   
   #CALLER_PIN only needed to send using sandbox number. Looks like 9999-9999
   CALLER_PIN = "put_your_sandbox_pin_number_here"
   
   

4. Then in a method in that controller try this:

   
   #Text message info
   t = {
     'From' => CALLER_ID,
     'To' => "replace_with_your_cell_num_in_parentheses",
     'Body' => ("#{CALLER_PIN} Twilio scales!")
   }
   
   begin
     account = Twilio::RestAccount.new(ACCOUNT_SID, ACCOUNT_TOKEN)
     resp = account.request("/#{API_VERSION}/Accounts/#{ACCOUNT_SID}/SMS/Messages",
                'POST',
                t)
     resp.error! unless resp.kind_of? Net::HTTPSuccess
   rescue StandardError => bang
     #This area will be called if an error happens with the Twilio API
     redirect_to({ :action => :index, 'msg' => "Error #{ bang }" })
     return
   end
   
   redirect_to({ :action => :index, 'msg' => "SMS sent." })
   

5. Then you should get a text message that says: “Sent from a Twilio Trial Account -9999-9999 Twilio Scales!”
6. Now that you have it working with a sandbox number it’s easy to to switch to a real phone number. Just go into the “Numbers” section of your account and buy an outgoing phone number. Give the phone number an SMS URL. I just gave it the url of my app.change out the sandbox phone number
7. Then use that new phone number instead of your sandbox phone number and delete the CALLER_PIN from the top and in the body part of the text message you are sending.

If you found this post helpful please link to it from your blog or website. Leaving comments below is also cool. Thanks!

HOW TO: Design and Program a Facebook Landing Page

I would keep these 2 important things in mind:

• Externally load all your images and css with absolute URLs
• Write HTML and CSS just like normal except you can add specific facebook tags in to enhance your content
• Yes, you can make forms.

It’s so simple and awesome.

Step 1) Surround your html tag with conditional statements like so:

<!--[if lt IE 7 ]> <html class=”ie6″> <![endif]-->
<!--[if IE 7 ]> <html class=”ie7″> <![endif]-->
<!--[if IE 8 ]> <html class=”ie8″> <![endif]-->
<!--[if IE 9 ]> <html class=”ie9″> <![endif]-->
<!--[if (gt IE 9)|!(IE)]><!--> <html class=”"> <!--<![endif]-->

Step 2) In your css just preface your targeted ie styles with the class name of the html tag you are targeting like so:

.ie6 h1 { color:red; }
.ie7 h1 { color:green; }
h1 { color:black; }


Super easy to target any version of IE without having to remember hacks or keep all your ie styles seperated in seperately served stylesheets.

Originally discussed here: Conditional stylesheets vs CSS hacks? Answer: Neither!

Here’s you you make a link that shows and hides content on you page:

$("#toggle_link").toggle(
function() {
$(".extra_info_text").show("fast");
$("#toggle_link").text("Hide Extra Info");
},
function() {
$(".extra_info_text").hide("fast");
$("#toggle_link").text("Show Extra Info");
}
);