If you’ve been following some of my most recent posts (and I hope you have!) you will have seen several different clock designs. While they are quire different, they share several things in common – namely being built on an Arduino platform, incorporating a DS3231 Real Time Clock (with battery backup) and driving some number of addressable LEDs.
While I have built prototypes using the UNO, Nano and Pro Mini Arduino boards, I needed a more cost-effective solution. I designed a PCB to take an Atmega328 and its associated components, the RTC module and a 6-pin header for a removable FTDI USB interface module (only required to download software). While this is a very simple design I added headers for all analog and digital pins. I created the schematic and PCB routing using the free Fritzing software. The software is pretty intuitive and comes with a large library of pre-defined components, although I did find it challenging to create and edit new components. Nevertheless, I’ll use it again and recommend it to others.
I read a message on a local bulletin board that mentioned Dirty Boards, a Hong-Kong based low-cost, no-frills PCB manufacturer. I uploaded the boards’ design files (more on that later) and 3 weeks later (and $24 lighter) I received 12 (not the 10 promised) boards. Excellent!
As you can see, I chose a white coating for the boards but they offer many colours at no extra cost. The plating is excellent and the boards soldered easily. The component silk-screen is clear but all over the place – my fault because I didn’t bother to take the time to pretty it up. The boards are clean and tidy and look very professional.
Dirty Boards allows you to upload your design files directly on their website. I exported the files from the Fritzing software in “Extended Gerber” format. However, when I zipped and uploaded them, I received the warning “Problem “PCB #2183: No board outline (.GML/.GKO/.GBR) file found. ”
!!! @#$% !!!
The Frizing “Extended Gerber” export produces a whole slew of files: top and bottom copper, silk, and mask; a drill file (in g-code) and a series of contour files. All well and good but there was no “.gml”, “.gko” or “.gbr” file, files that the Dirty Boards site was looking for. However, one of the contour files had a “.gm1” extension – something I’d never seen before. I searched the Internet but could not find any reference to this file format. In desperation I changed the file extension to “.gml” (not generally a good idea!) and uploaded the new zip file. Stone the crows! Much to my surprise and delight the website accepted the file and showed the following images of the top and bottom copper. A handy little feature that gives you “warm-and-fuzzies” that all’s well in PCB land!
Conclusion: Dirty Boards was easy to use, cheap (only $14 for 5cm x 5cm boards), delivered more boards than they promised (12 rather than 10). To cap it all, the boards are nice looking! So, when I need a PCB manufacturer, I won’t hesitate to use them again!