Friday, March 25, 2016


The idea and the proof of concept

I use EAGLE, LTspice and a lot of other programs which gain a lot of more power an usability if the commands of the Hotkeys are known. But the main problem is that these program have all different Hotkeys/Commands which will vary from [CTRL]+C over the command "copy" to [F6] for copy something.

Even though I know most of the Hotkeys for each program I have often the problem to mistake them when I quickly switch between the different programs. So I thought about that problem and how I could get rid of it. I saw an Arduino sitting on one of my shelfs collecting some dust and I came to my mind that this litte device can "fake" the behaviour of mouse and keyboard on a computer.

I used this feature of the Leonardo before as it can be seen in one of my previous articles. So I've decided to give it a chance to solve my problem.

The proof of concept

I wired up a "shield" with some buttons for my Arduino Leonardo to test the concept and how I would like it.

I Know it looks ugly but it has worked quite well. Below I prepared the schematic for this shield to get a quick overview over the wiring.

The Shield has nine buttons for the Hotkeys and two to select the current configuration. I also added a RGB LED and a 16x2 LC-Display through the I2C connection to show additional information on the currently active configuration. It also got a connector for the serial output for debugging purposes.

All buttons are biased trough the internal pull up resistors of the MCU so that they switch to ground when they are pushed. This saved me 11 Resistors of wiring effort for the board.

I've added the corresponding Arduino sketch to my github repository. You will need a library for the I2C connection of a LC-Display or just comment the line with the definition of LCD_I2C_ACTIVE out.

#define LCD_I2C_ACTIVE // Uncomment to activate the LCD Output

After some tests...

... I decided that I should follow the idea with a HotKey pad to increase the usability of my favourite programs. So stay tuned for the upcoming articles if you want further information about the HotKey pad.