LCD clock version 2 – part II


Here’s an update on Kevin Rye’s LCD clock we covered previously.  Source files are available here, for direct download

Once all the components and headers were soldered in, I attached my Arduino and configured it as an ISP. I then burned the bootloader for an Arduino Uno.
I then connected my FTDI programmer and uploaded the blink sketch.Success!
Wow, that LED is super bright! It’s actually blinding and kind of hard to look at. With that, I swapped out the resistor for a 1K one in order to bring the brightness down.
Knowing that the Atmega worked, it was time to solder in the rest of the components, except for the display. Again, I don’t want to come this far and then waste a $15 LCD.

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  1. Was it really 93F in the room? When I implemented my GLCD clock I had to do a correction on the temp. reported by the DS3231 RTC IC. The temp. value it reported was always too high, presumably due to internal self-heating, and heating by adjacent board components. I measured the actual room temp. vs. the reported temp. across a wide temperature range, and then built a correction table.

  2. Unfortunately, yes. It was a very hot day, and all the tech in this room doesn’t help either. I refuse to put the AC on yet, or come July/August, I’ll never make it.

  3. PS – I’ve built several clocks with the DS3231 reporting the temp, and they’ve never been more than 2 degrees off the 2 other temperature monitors I use for comparison. My computer room is always a good 10 degrees hotter than the rest of the house. It’s not uncommon for the room to be 85 degrees when the rest of the house is nice and cool. However, now I wonder if there is some extra heat coming off the display though. I’ll have to check it again. Thanks for pointing that out. I looked at the 93 degrees and thought nothing of it.

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