plot thermometer / clock EXPO pen parts

These EXPO fine point dry erase pen compatible parts are for use with smily77's "v2 version" of the plot clock / thermometer:

https://www.thingiverse.com/thing:371248

Actually it's technically not a remix rather than a redesign, since the mesh kept breaking when I tried 'remixing' the original STL's. So I redrew the parts from scratch using freecad. As a bonus the STL's are higher resolution, and it becomes easy to create STL's to fit other pens as needed. The Freecad file is included in case you feel like doing just that.

I also uploaded Plot_thermometer_Clock_final_V1_1c.ino with several improvements & fixes:

--Always lower the pen to "lift(0)" while parked. This helps get a tighter seal between the marker and eraser/cap when not in use.

--Added option to show time in 12hr format (removed the leading "0" from 12hr format).

--Added option to show temperature in Fahrenheit.

--Added ability to display temperatures >=100 (...use Fahrenheit on hotter days too).

--Added an option to select either PIR or button for pin7, and fixed pin7 input setup. 1_1b when used with existing wiring schematics would alse require a momentary N.C. type button for proper operation. Since N.O. type are more common, 1_1c uses a momentary N.O. button wired between pin7 and Vcc. The default is PIR enabled; so 1_1c is backwards compatible with 1_1b with no required changes.

--Changed "1" to look more like a "1" and less like a "7".

--Changed "4" to look more like a "4" and less like a "9".

--Changed "." so it's closer to the bottom, rather than the middle. Also moved it to the right for a better look.

--Fixed double erasing of board after waking up from standby (since board gets erased before going in to standby).

--Added erase board during bootup (goes along with the above 'double erasing' fix).

--Move minutes '2 units' right, and move ":" '1 unit' right for better spacing (now the ":" doesn't disappear at XX:3X time).

--Added include TimeLib.h to fix compiler errors with windows based IDE's that have a (lower case) time.h library. Note some windows based IDE's may also have compiler errors due to 3 lower case e's used in the default Arduino EEPROMEx library. If you have this issue, rename EEPROMex.h and EEPROMex.cpp to EEPROMEx... and similarly change the include at the top of EEPROMEx.cpp to EEPROMEx.h... should get you going.

Some observations:

I used some micro servos that came with an eflite blade CP helicopter I had a while ago (hxt900ish size), and they didn't quite fit smily77's frame. Plus I was unsuccessful at getting those print in place hinges working. So I used this version from stylesuxx with success:

https://www.thingiverse.com/thing:940737

Besides being much easier to print and get working, it has a simpler and more durable servo carriage that is designed so it will fit a broader range of servo choices (thanks to the thicker flanges slots and room above and below the servo). I added some scrap plastic shims under the servo mount flanges to get a nice tight fit on my servos (with thin flanges), and there's room for thicker flanges like those found on hxt900's.

I ended up using a Turnigy MG14 servo for lift. I think most micro servos like the hxt500's are just too weak for the task. Also, my eflight xy servos (similar to hxt900) are working ok, but if you are buying xy servos for this thing try and get the best you can afford. The kinematics involved here will benefit a lot from precision (you'll get much cleaner digits). If you can afford them, digital servos with good slop free gears will do much better than cheap and sloppy servos. Having been in the rc hobby for a few decades including high performance helicopters and pylon racers, I will say in general you get what you pay for with servos.

Update 8-20-2018: sweeper_expo1_1.stl

I was experimenting with a better seal on the Expo marker, and thought that force from the angle of the marker as it is parked may cause problems. I measured my rig and it rests at 7*. So I made another sweeper that sits at the proper angle.

Update 8-23-2018:

I bought some Expo chisel tip pens at Sam's Club, and made some parts to go with them here:

https://www.thingiverse.com/thing:3064267

Category: Robotics