Summary

An automated turntable to keep your houseplants from bending towards the sun

Description

This is a 160mm (6.3 inch) turntable that moves slightly more than 1/3 of a revolution each day. By reorienting each day your plants never have a chance lean towards the nearest light source so they end up growing straight. The project uses an Arduino Nano clone and an inexpensive stepper motor and sensor. All components are available on Amazon, or on Ali Express at lower prices if you're patient and adventurous.

STL files

The project .stl files are all that's required to make one of these. But if you wish to make modifications, This is a link to the TinkerCad project. The designs within the project still contain most of their component shapes, and so are much easier to tweak.

Components

• Arduino Nano clone
  The Nano boards used must come without headers attached as they are always mounted on the bottom of the board when the board is pre-assembled. This design requires the headers to be mounted on the top of the board. These Nano clones with Type C USB connector and headers not pre-soldered seem to work reliably: Amazon Link
  There are others available with Type C or Mini connectors. Either type should fit. I tested the fit with various older Mini types but haven't purchase any recently. Note that the older Mini versions generally require you to select Nano (Old bootloader) when loading the sketch, and the newer Type C boards come preloaded with the new bootloader. Both require a CH-340 driver to be installed if loading from a Windows box.

• Optical sensors Amazon link
• Motors With driver boards Amazon link
• 1/2 inch ball bearings Amazon link
• #4 x 1/4 inch screws Amazon link
• 8mm x 2mm screws (for sensor) Amazon link
• Wire: I used stranded AGW 26 and Dupont connectors. You can of course solder directly on to the components or use breadboard style F-F jumpers if you choose.

Printer Settings

• Setting	Value
  Printer brand	Prusa
  Printer	MK4S
  Setting	0.20mm STRUCTURAL
  Supports	Everywhere
  Infill	15%
  Filament brand	Inland
  Filament material	PLA+

• Custom settings
  I built these with one Prusa slicer setting customized: Advanced - Seam Position: Random. Cura has what appears to be a similar setting: Z seam alignment, that can be set to Random. This causes the slicer to select a random seam position for each layer and rotation on circular features. The reason being that if they are aligned, as is the default, you end up with a noticeable bump all the way across the rounded ball bearing tracks. With heavy loads(>10 lbs) that bump can cause rotation to get stuck, even at slow rotation speeds. The Random setting causes many tiny bumps that don't seem to interfere with smooth rotation.

Connections

It is important to route your wires in a way that keeps them low in the assembly. The protrusion on the bottom of the platter can get caught on any loops sticking up.

Code

The included .ino is self-contained and does not require any 3rd party libraries.

Variables

The speed in the .ino(MOTOR_SPEED) is set at 6 RPM . That should work for most cases. Note that these cheap little steppers don't have much torque. Reducing the speed to 1 or 2 increases the torque by giving the motor more time to pull the armature to each stop. Also, the power supply can come in to play. A 1 amp charger might be less than required for heavier plants. I've tested with 15 lbs. 2 amps and 2 RPM definitely work where lower values for either can result in rotation stopping.