I admit it: I'm a total geek. I love electronics, programming, 3D art, vintage Apple hardware, and whisky. I'm always juggling half a dozen projects. I also enjoy documenting it all: my successes, my failures, my experiences... and everything geeky along the way.

Seeed Studio Fusion - $9.90 for 10pcs 2 layer 10x10cm boards


Mini 7-Segment Clock V2, Part II | Kevin Rye.net - Main

Kevin Rye

Geek Extraordinaire. Yeh, I said it.

Mini 7-Segment Clock V2, Part II

I received the PCBs for version 2 of my Mini 7-Segment Clock. They look awesome!


I managed to make it 10mm smaller than version 1 by swapping out the 28-pin ATmega328 for the SMD version. Although it’s that much smaller, I was still able to add an ICP and FTDI header.

Here's a side-by-side comparison with version 1. It's so much smaller that I should have called it the Micro 7-Segment Clock!


I didn’t want to put the whole thing together and find out that it didn’t work. That would have been a waste of components. I decided to only solder in the ATmega, the 16MHz crystal, and the supporting caps and resistors; just enough so that I could test loading the bootloader onto the ATmega and upload a sketch.

miniclock2assembly_0023 (1)

I configured my Arduino Uno as an ISP and attached the Mini Clock’s 6-pin ICP header to the Arduino via a ribbon cable and some jumpers.

miniclock2assembly_0004 (1)

I then jumped into the Arduino IDE and burned the bootloader for an Uno. After the bootloader was successfully loaded, I connected my FTDI adapter and uploaded the blink sketch. I then jammed an LED into my PCB and watched the LED blink. Success!

miniclock2assembly_0006 (1)

After validating ICP and FTDI functions, it was safe to go ahead and solder in the rest of the components.



Now for the moment of truth. I crossed my fingers and connected a battery pack. Woo hoo! It works! I love that feeling you get when you spend weeks working on a project, it all comes together in the end and it just works.

miniclock2assembly_0006 (2)

With the electronics working, it was time to put it in the enclosure. I cut the end off a SparkFun 5V DC power supply and soldered on a 2-pin Dupont connector. I then secured everything with a little heat shrink tubing.


I then took the acrylic panels that I designed and had laser-cut from Ponoko and secured them to the clock via some screws and standoffs.


It looks amazing! I’m really happy with the way that it came out. I also really like the “kelly” green segments on this display.

miniclock2assembly_0008 (2)

Here’s another side-by-side comparison with version 1. I remember being so pleased with version 1 after I made it. At the time, I didn’t think I could make it any smaller, and yet I did!


I wonder how much smaller version 3 will be? Nah! I think I’ll quit while I’m ahead! Besides, I don't think I could make it any smaller without using a smaller display.

See this project from start to finish:
Mini 7-Segment Clock V2, Part I
Mini 7-Segment Clock V2, Part II