A few weeks ago, I gave into my insatiable lust for building clocks, and picked up the parts to construct this awesome clock.
I know, I know… Broke college student should probably not be spending what little funds he earns on MORE electronics… I think as I punched in my credit card number, I’d convinced myself that it was somehow school related, or at the very least educational. And therefore a justifiable expense…
It’s a pretty neat little project, the gist of it is this: A tiny microcontroller designed by Adafruit called the Trinket uses Pulse Width Modulation to control two ammeters. By varying the relative current through each meter, one can be read as an hour output, and one a minute output… Sexy!
During the build of this project, there were many opportunities to learn. (Read: I screwed a bunch of things up completely.) I’d never used a Trinket before. Getting it set up on my computer turned into sort of an ordeal. There are two methods to configure the Trinket, and while they’re similar, they are not the same. After banging my head against it for about 10 hours over the course of two days, I finally asked for help in the Adafruit support forum, and within two posts they quickly diagnosed where the problem was, and in turn I figured out what I was doing wrong.
(I had been modifying a config file for one method (AVRDUDE), when I meant to be doing it for the other (ARDUINO)…)
Asking for help is hard sometimes. A habit one would do well to develop before their mid-thirties. It’s a humbling experience to say “I can’t do this solo”, and I’ve had to do it a lot more often recently. It’s getting easier, though still pride still trips me up on occasion. Anyway…..
Once the Trinket was happily blinking along with the test LED pattern, it was time to move onto something a bit more fun: Building the circuit! I’ve done a bit of breadboarding, and had already finished making the circuit before I even had the Trinket up and running. Sadly, there’s not a picture of it, it was beautiful. Since this is to be a permanent addition to the clock collection, it needed to be made a bit more permanent. Fortunately, there’s a solution for this problem: Protoboard!
Now, this was a first. In this past I’ve put together kits from other people, but I’ve never had the freedom to lay out the components any way I want. A bit intimidating initially, but kind of nice, in the end. I opted to use rows of headers instead of soldering the Trinket and the RTC onto the protoboard. Something in me said “You never know when yo’re going to either a) want one of those components for something else, or b) need to replace them.”
Here’s a look at the top of the curcuit:
And here’s one of the back:
All powered up:
Detail of the meters without the hour/minute face plates in them:
- Read instructions slowly, and when you aren’t frustrated. The potential to misread things seems to be higher at those times.
- Keep in mind what Mitch Hennessy had to say about assumption.
- Leave a little wiggle room on the protoboard.
- Draw out a full design first. Even if you’ve already made it on the breadboard.
- Don’t be stingy. Buy some of these boards. Then you can use the exact layout from the breadboard.