Everything for Electronics
Posted in: Developing Perspectives (August 2014)

The DIY Differential

By Bryan Bergeron

The Chinese-manufactured clock performed flawlessly ... for about a week. Then, the display was nothing but random LED segments. When I cracked open the case, I found nothing in the way of user-serviceable parts. Everything was soldered in place, including the main IC which looked like a spider epoxied to the motherboard. So, there went $15 plus a lot of time and trouble. I ended up using a different time-keeping system for the project, and all was well.

After the crunch, I revisited the world of large digit LED clocks. This time, I went for the $90 kit. After three hours of soldering and a bit of sanding, the clock was ready for mounting. Although I haven't exercised the option of reprogramming the clock to, say, a countdown timer, it's only a matter of Arduino programming. 

Plus, there's a small breadboard area on the clock's motherboard. Moreover, I know that if the clock suddenly dies, I can resuscitate it by replacing the failed components and reloading the Arduino program if necessary.

Is this to say that relatively expensive kits are the only way to go? No — sometimes you just have to go with off the shelf, affordable, and sometimes cheap options. When you do have to decide, just make an informed decision. Is there something to learn from, say, building your next clock, radio, timer, LED display, or other circuit, or is your time spent better elsewhere?

It's a personal choice, and one that depends on your level of mastery in a given area — and, of course, budget. No need to twiddle with an LED project if you're looking to learn about digital signal processing (DSP) techniques. It’s better to pick an analog-to-digital converter project.

By the way, the $90 DIY clock is still running months after the $15 clock's demise. If and when the DIY clock dies, I'm sure I'll have the means to repair it. Sure, I could keepbuying $15 clocks, but I'd have to deal with the uncertainty of the cheap versions failing at the worst possible moment, and the moral implications of constantly contributing to landfills. Keep building! NV