Turn table

I've built these projects to present a kind of trophy.

Idea

trigger the turning action by the presence of someone passing along. Of course, the code can be modified easily to run more turn, eg. to support some scanning (e.g. 3D scanning with Qlone)

Concept

Arduino based µC runs a stepper motor after some trigger has initiated actions

Construction

You'll need as mechanical parts:

• screw M6x25 countersink head screw 1x plus nut 2x
• bearing outer diameter 16mm, inner dia 6mm
• wood screw M3 4x
• magnet dia 5mm, thickness 2mm
• wood according to your dimensions

first build a wooden or printed box, I found the measure of 13cm x 8cm x 5cm as a good fit. The only relevant measure is the distance of the center holding the bearing and the position of the gear wheel. Simply take the measures from the drawing below.

Gearing mechanism requires two 3D prints.

First the gears

and in addition support for the bearing (to keep it positioned in the wood) as well as for the nut

The turntable itself should be something between 13 and 15cm in diameter. Place a sunk hole in the middle so a screw M6 will fit.

the the gear ring is also a hole for a 5mm magnet. This will allow to use the hall sensor and find the zero-position during init. For drilling, you can use the template from the Github page.

Topside of the box shall be drilled according to the below drawing and the result looks like the photo (bearing and bent hall sensor placed on top)

Electronic hardware

Besides an ATMega8, Arduino Nano or Uno you'll need a motor with driver stage, radar sensor and eventually DC/DC converter.

Sources for the hardware could be:

• Arduino Nano (clone) -> Banggood
• 28YBJ-48 DC 5V 4 Phase 5 Wire Stepper Motor With ULN2003 Driver Board -> Banggood Datasheet
• eventually DC/DC converter -> Banggood
• RCWL-0516 radar sensor -> Banggood
• Hallsensor e.g. A3144 -> Banggood

Code

You'll find the code in my GitHub folder here.

I run my code on a ATMega8 however you can easily adapt to a standard Nano or other Arduino board; in the settings.h all pins a clearly defined and can be adapted easily.

After the initialization, the motor turns until the hall sensor detects the magnet, which indicates the starting position. From now the radar sensor waits for motion and triggers one turn of the table. Once done, the program is waiting for the next radar detection.

That's all - Happy presenting !!