LED Countdown & USB Button

Other Hardware LEDs and Multiplexing
1

Hello,

This is my first post on these forums. I'm a total noob, but I'm learning a lot from poking around and reading.

What I'm trying to build is a USB button that will trigger a computer keystroke ("F4" for example) as well as a LED animation.

Essentially, when a user presses the button, I want the button to tell the computer to press "F4" then trigger a countdown light made up of LED lights.

This is the button I'm thinking about using:

And this is a similar animation I want the LEDs to do upon button press:

The LEDs will be arranged in a circle (approximately 12 inches in diameter). When the button is pressed the LED ring will start lighting up clockwise. Ideally, 'd want to be able to program the amount of time it takes for the LED ring to light up 2 seconds, 5 seconds, 10 seconds, etc...

Again, I'm just starting to dive into Arduino so I apologize again for not being very well versed on this subject.

If anyone can give me any information or point me in the right direction, that would be awesome.

Thanks so much in advance!

2

Blinking LEDs is exhaustively demonstrated on my website http://www.blinkenlight.net. I also have several examples how to implement the Larson scanner effect you want to achieve.

3

What I'm trying to build is a USB button that will trigger a computer keystroke ("F4" for example)

This is not a project for a self confessed "total noob".
It could be tackled in two ways:-

  1. Make a USB host shield and write an HID host keyboard adapter sketch. Not an easy thing.
  2. Have an other program running on the PC that looks at the serial port and injects characters into the input buffer when it receives them from the arduino.
4

Well, I thought this is a very easy project.

My approach would be:

  1. Arduino + Blinkenlight code for the LED effect
  2. Keyboard controller out of old keyboard for sending F4
  3. A button that will trigger both at the same time
5
  1. Keyboard controller out of old keyboard for sending F4

Well he did say:-

computer keystroke ("F4" for example)

Which implies he is wanting to send more than one key press.

6

Thanks so much! I'll look into your site and do some more research.

7

Grumpy_Mike:

  1. Keyboard controller out of old keyboard for sending F4

Well he did say:-

computer keystroke ("F4" for example)

Which implies he is wanting to send more than one key press.

I'm only trying to trigger one computer keystroke at a time, but wanted the option to change the keystroke if needed. Thanks for your help!

8

but wanted the option to change the keystroke if needed

Well that option would involve soldering two wires across a key and you would have to change the soldered wires to change the key.

9

Grumpy_Mike:

but wanted the option to change the keystroke if needed

Well that option would involve soldering two wires across a key and you would have to change the soldered wires to change the key.

What about something like this?

10

Yes that looks like it has most of the ingredients for your application.