2015-03-17 (Tu) 3D Printed Automatic Tea Maker

A new set of the revised parts were printed. These revised models corrected the known problems with the first set including a base which wouldn't fit some larger mugs, a platform which didn't fit a servo motor and a key which was not long enough and didn't fit a servo horn well. A bolt hole in the base piece did not line up so it was remodeled and printed after the error was noticed in the print.

 3D models in the printing software

Corrected base piece in the printing software

 Printed parts

 First versions on top, revised on bottom, faulty base in lower left

The 16 x 2 text display showed the correct start up sequence but quickly became nonsense when the program was running. The initial display was encouraging since it demonstrated that text could be properly displayed and the problem was not a wiring issue. To diagnose the problem some lines and functions were removed until the problem disappeared but the majority of the code was disabled. The problem was elusive but tracked down to a function which was supposed to return a text string but returned nothing so the program spewed all its data. This was the problem with the HEARTBLEED security hole.

 Properly displayed text

Nonsense on the screen

The servo motor functioned well without any need for code modifications. The angles had to be adjusted so nothing would collide. The unit was assembled when the angles looked good. All the 3D printed parts were put together and fit well. Hardware store bolts in 4mm and 5mm were attached with nuts purchased at the same time.

Videos were made to demonstrate the tea selection potentiometer and the function of the tea maker. The times displayed in the video where the tea maker lowers the servo for a few seconds were modified for the video to demonstrate proper timing rather than accurate tea steeping times.

Selecting a steep time and seeing the corresponding tea names

Demonstrating the tea maker with a shortened time

To do:
  • Solder
    • Repair
    • Attach selector pot
    • Correct potentiometer
    • Replace speaker
  • Download and test code
  • Debug code
    • Reduce jitter in timing
  • Hardware
    • Make power supply go to servo power
    • Add 5-6V power in
  • Make code public
  • Design enclosure for screen, potentiometer, power, and buttons
  • Print enclosure
  • Draw schematic

The rest of the posts for this project have been arranged by date.

A list showing of all the final posts of COMPLETED projects.

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2015-03-09 (M)