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I have been busying myself recently with some experiments into programming the Arduino prototyping platform. 

I have already created some hardware, a Maxim DS1307 Real Time Clock shield and a Serially Interfaced, 8 digit 7 Segment Display based on a MAX7221 IC.  So far I have created test routines to test my hardware but I wanted to really get my teeth into creating some more practical code. 

And here it is, A more or less functioning LED clock. 

I have included a download of the sketch (Arduino speak for program) that I wrote so that Arduino owners can examine and play with my code, There is a cheesy video blog at the end of the article as well if you want to see the clock in action…

I recently built a Serially Interfaced, 8-Digit, 7-Segment, LED Display module to use with my Arduino. Of course once you have built such a module you need something to run on it to test it functions correctly. What was needed was an Arduino sketch that wrote values to each of the 8 digits of the display and also that would amuse me.

Think 7-Segment, LED Displays and you cannot help but think of the standard displays of heinous bombs in action films or that frantic TV series 24. I could think of nothing more fitting to test my new display than a countdown timer! Here is the code and a short video of said timer in action.

In a lot of your electronics projects you may need a display to provide information to your users.  These days the project builder has a plethora of options to consider when deciding on a display.  The needs of the project will dictate to some degree what technologies suit. 

The first thing to consider is what types of data you wish to display, do you wish graphical, text or will a numeric display suffice?  Next we must think about the look of the display and the readability.   Different technologies (i.e. OLED, LED, LCD, OMED) all have their own visual signatures and limits and benefits.

This project uses 7-Segment common cathode numeric LED (Light Emitting Diode) displays.  The 7 segment display has been around for years and gives projects a cool retro look.  Readability is very good from this technology and displays are available in a multitude of sizes.  So for projects that need to be read at a distance this is a very scale-able option.  Thanks to the Maxim MAX7221 IC (Integrated Circuit) it is also very easy to control these LED displays using a microcontroller such as the AVR processor within an Arduino.

I  have been interested for a while in the Arduino, an open source development platform based on the AVR series of microprocessors.  In case you have not heard of the Arduino before, there are many variants but all share the same footprint and are extendable using stacking circuit boards named “shields”.

I eventually wish to develop my own volume control setup for an amplifier, but in the meanwhile I have to learn how to code.  To that end I needed some hardware to attach to my Arduino (well Seeeduino to be more correct) and cut my teeth on.

So I have built my first shield, an I2C clock using the Maxim DS1307 RTC (Real Time Clock).