Building a Mini 7-Segment Clock (V2)

Kevin Rye recently re-designed his already impressive Mini 7-Segment Clock using an SMD version (instead of 28-pin DIP) of the ATmega328 microcontroller (MCU) and a custom PCB.

“I moved the switches a little off-center to the right and shuffled everything else around in order to fit the SMD ATmega,” Rye explained in a recent blog post.

“I rotated the ATmega 45 degrees. I think chips look cooler when they’re rotated, but in all seriousness, it is easier to run a trace from one side of the board to the far side of the chip when it’s rotated.”

Rye also moved most of the (PCB) text from the front to the back. However, with the exception of the ICP and FTDI headers, the board layout remained the same.

 After receiving his new PCBs, Rye decided to kick off a limited test of his new design.

“I didn’t want to put the whole thing together and find out that it didn’t work, [so] I decided to only solder in the ATmega, the 16MHz crystal, and the supporting caps and resistors – just enough so I could test loading the bootloader onto the ATmega and upload a sketch,” said Rye.

“I configured my Arduino Uno (ATmega328) as an ISP and attached the Mini Clock’s 6-pin ICP header to the Arduino via a ribbon cable and some jumpers. I then jumped into the Arduino IDE and burned the bootloader for an Uno.”

After successfully running the bootloader, Rye connected the FTDI adapter and uploaded the blink sketch, jamming an LED into the PCB and watching the LED blink. Last, but certainly not least, Rye validated the ICP and FTDI functions and soldered in the rest of the components.

Interested in learning more about version two of Kevin’s Mini 7-Segment Clock? You can check out his detailed project blog post here and download the source files here.