Arduino-powered alarm clock

cults3d

An alarm clock that I built sometime ago serves merely as a point of inspiration; the electronics were largely pieced together on perfboard; replicating it might be quite challenging. Powered by an Arduino Nano Pro, a SI4702 FM radio (connected via level shifters), a DS1307 real-time clock and a compact audio amplifier. The display is based on four MAX7219 LED matrix modules sourced from aliexpress. The left- and right hand side of the panel feature press-fit holes for 4 small 28mm speakers. The display modules are mounted on an insert, situated at the front of the clock. On the rightmost module, the 8x8 matrix has been replaced with a daughterboard featuring a 4-digit 7-segment display and some status LEDs. It is slightly offset to compensate for the difference in height. To enhance contrast (and reduce brightness), it is mounted behind tinted acrylic glass (my local supplier did not have acrylic that was very dark, so I ended up using two layers). Top and bottom are attached to the side panel using self-tapping screws. These might strip out after opening and closing the clock a few times (I ended up updating the firmware more often than I'd like to admit); inserting a match into the posts seems to work just fine to provide more grip for the screws. I have included the OpenSCAD source code. It's not very pretty, and it may not be the best way to achieve things. The source code can be found at https://github.com/pienjo/ClockRadio