arduino based multi-function display for Vanagon - part 4

As in any design development, there are challenges with the parts that one specified. I happened upon the DHT11 temperature and humidity sensor because of its dual function. It would turn out it was fun while the curiosity lasted. I have 3 of this and found that they are worthless junk. The temperature reading often jumps around 2 degrees, and at time 8 in consecutive samples. Also all three are extremely inaccurate. I had play with the Maxim DS18B20 quite early on and found them to be very accurate for solid state active sensor. One reason reason that I didn't choose it was my attracted to the DHT11's humidity capability. The bigger reason is the library for the DS18B20 is very memory intensive, and I had ran out of program memory as well as SRAM.

arduino based multi-function display for Vanagon - part 3

When I first embark on this project, I only have a vague idea of the list of features I want. It was just a preliminary list of requirements. Oil pressure and temperature, interior and exterior temperature, and most import a data logger.

arduino based multi-function display for Vanagon - part 2

I added a clock and calendar screen. It took a bit of work to sort out the navigation logic since this is a new feature that I didn't plan for. With each feature that I add, it had been a hand-to-hand combat to conserve precious memory, both the flash and the static RAM. The latter is most critical as there is only 2k bytes. My goal is to have a least uncommitted 512 bytes left. The power management features that I implemented is working very well now and appears to have few bugs. The joystick UI is very smooth without mis-registration. I also managed to add time stamps to the file creation and modified.

isolde's muffler

Isolde was my first love. We met twenty-six years ago.