Googly eyed Minion clock

thingiverse

This remake adds new software and hardware to gwfong's Googly Eyes Minion Clock remake based on Minion Dave by Poh. I created a PCB that holds a ULN2803A octal darlington transistor array to drive two stepper motors. It also contains a DS1302 real time clock chip, its crystal and battery. The board is driven by an Arduino Pro Mini. Eagle files are included; I used the toner method to create the board. The software supports two buttons. The MIDNIGHT button tells the software where the 12 O'clock position is. You can rotate the eyes with your fingers and press this button when they're in the correct location. The MODE button switches between clock mode and one of four random animations. The RTC needs to be set via the Arduino IDE Serial Monitor when the FTDI programmer is present. Send the date and time in the form yyyy,MM,dd,hh,mm,ss, and the software will program the RTC. I sourced my parts from eBay; they're all easily obtainable. I got the DS1302, crystal, and battery holder from a cheap RTC board. The only 25mm stepper motors I found were on eBay. These motors are fragile with very poor resolution - 24 steps per revolution, making the minute hand move 2.5 minutes on each step. They also have no gearing, so they don't have much torque. The software can accommodate higher resolution stepper motors. If you modify this design to use 28BYJ-48 stepper motors, for example, you can change the defines at the start of the code. You may need to reduce the RPM speed for higher resolution stepper motors.