The clock wants some brains, so it is time to hook up the microcontroller.
First, you will need to program the Arduino earlier than putting it within the circuit. The code I used (WordClockModified.pde) is a barely modified model of drj113’s authentic code, up to date in order that the pinouts match my model and I modified the buttons to be hour-advance and minute-advance reasonably than minute ahead/backward.
Space-wise, you most likely will not be capable of match the entire arduino USB board contained in the body, and there is not any cause to anyway, so I selected to arrange a standalone ATMega168. If you do that ensure you use a crystal, not a resonator – resonators are easy since you do not want separate capacitors, however crystals are typically extra correct which is necessary in a clock.
For essentially the most half I adopted drj113’s schematic with a couple of modifications:
– I connected the output-enable pin of the shift registers to a PWM pin on the ATMega168 (as a substitute of simply tying them excessive) in order that I might dim the LEDs programmatically
– I added a potentiometer to an analog enter pin for setting the brightness (you may substitute a photoresistor so the lights dim when it is darkish)
I’ve uploaded a mini-schematic I drew to assist wire the parts (Note: the pinouts on my model are totally different than these utilized by drj113)
To begin constructing the controller, chances are you’ll need to use a breadboard to prototype among the design (picture 1). Once you’re satisfied that issues are working as anticipated, it is time to transfer to a extra everlasting structure.
Start by reducing down a chunk of protoboard and laying the parts out to ensure every little thing matches OK (picture 2). Then begin wiring up the parts. I began with the voltage regulator and ATMega168 and made certain that the microcontroller was connected accurately earlier than persevering with (picture three – word: the highest of the board was fairly cramped, so I wired up some issues on the underside facet). Then I wired up the shift-registers and drivers, checking to make it possible for every set labored accurately earlier than persevering with (picture four exhibits the board after two units of shift-register/drivers have been wired). The accomplished controller board might be seen in images 5 and 6.