Mostly Done

A project log for Intervalo-Thingy

ATMEGA 328 based intervalometer. Stupidly complicated for what it does. This is now its official name.

afro-spockAfro Spock 03/14/2016 at 23:240 Comments

So, I've actually finished this project more or less.

I used a dual channel optoisolator to fully segregate the mcu and camera electricals. Got a board etched. Killed the battery controller and simultaneously learned that making all the boards separable is nice and will be a design objective going forward. Bought a boost converter for AA batteries and installed it. Battery life is really, really long. I got mad at the tupperware enclosure and moved it into a cardboard box that sparkfun shipped me something in. Next I need to put a thick red filter on the lcd so I won't accidentally wash out my photos when I want to peek at the status while doing astrophotography. And maybe a grey one too. Dim and red is the goal at night.

So far it works pretty well. There are some things I want to improve, but I mostly did this project to advance my electronicals knowledge. The el-cheapo LCD I'm using has some quirks that I had to code around.

I guess I'll explain. The LCD is the wrong color. It's too bright. The backlight isn't an LED one. I wanted to use pwm and a transistor to control the brightness, but that doesn't work on this backlight. The details about it were pretty sparse when I bought it. It refreshes slow. Really slow. At first my code blanked the screen every five times through the loop as my method of getting rid of unwanted characters when we went from 3 digit numbers down to 2 digit ones. This was giving me headaches with all the flickering. I also tried this method on a nicer LCD that I henceforth killed. Worked ok there, but on this one it was terrible.

I got around this by only overwriting the characters when they change. Most of the display never gets blanked (unless switching the mode) which makes it a lot easier to look at. No flicker at all.

If I could do this over I would probably get one that is red on black with an led backlight. I still like the method of only overwriting characters that change instead of blanking the whole thing. It took a little more work but turned out better. And don't solder the LCD on permanently. Make it removable!

I'll get some pictures of it in its newest home posted. I'll throw my code up as well, if anyone is interested.