So, you haven’t seen an update out of me in a while. This is because I’ve been struggling over the past week with getting my clock to return accurate, or at least consistently inaccurate results.
Author Archives: ch00f
Me and the Cap’n
So, it turns out that clock crystals need a “load capacitance” between each of their two pins and ground. I’m not entirely certain what these capacitors even do, but I do know that they are critical to keeping good time.
That nixie tube clock that I made originally had a clock crystal in it that had no load capacitors. This resulted in it being inaccurate.
Tik Tok
I have a clock!
Dearly Departed
So today was something of a downer.
And the good lord said, let there be LED!
I think I’m thinking too hard
I’ve been pondering this current-limiting nonsense all day, and I think I’m overthinking.
The issue is this: If I want to get maximum brightness out of my LEDs, I’m going to want to overdrive them a bit because I can run them at a maximum of33.3% duty cycle (if I have three LEDs lighting up at the same time). LEDs that are rated for 20mA of constant current might be rated for up to 100mA of peak current. Apparently, nobody make a 40+mA constant-current LED driver that runs at 3V. Oh well. Continue reading
A greener watch
I’ve been thinking more about energy savings with my watch.
I’m already going to be using some kind of Real Time Clock chip so that it only draws a tiny bit of precious power from my battery when in standby, but what about when I power the thing on?
Well, LEDs aren’t current limiting. This means that unless you do something special, they’ll draw a ton of current (and if you supply them with enough current) blow themselves up or at least severely shorten their lifespan. Because of this, you always need to add a current-limiting resistor to protect them.
Here’s how it works: Continue reading
Soooo…what exactly happened last night?
So, after getting some sleep, I figured I’d update to discuss all the things I figured out.
Firstly, I got my new programmer!
Success! (sort of)
So, it’s very very late right now, and I have other work I need to do before bed, so lemme keep this short.