Component choice

A project log for Overtime: the internet connected alarm clock

We send about 35% of our day sleeping. What's the most important device for us during that time? Our alarm clocks, of course.

laurens.weynlaurens.weyn 08/20/2014 at 18:110 Comments

Right now, the prototype is not suitable for a production run with its current components. The display is actually an exchange rate sign from a bank and the main controller is a rather expensive Arduino Mega.

I used the mega mostly for future proofing and because my Uno was in use for another project, but an ATMega328 has enough pins to control all the needed components.

The exchange rate sign is basically a matrix of 7 segment displays. Shift registers on the left for the rows and a 4 bit decoder and some transistors to drive the columns. It’s pretty simple to replicate. However, the display is pretty big, both in size and in digit count. A production version’s display might be a little smaller.