Electric Lazy Susan – ElectroSchematics.com

Despite not being entirely clear where the term lazy Susan originated, one thing is clear. A lazy Susan is a revolving round tray that is meant to sit on a tabletop. If you have dined at a Chinese restaurant, you have likely used one there. Nowadays you can find miniature 360° turntable electric lazy susan in many contours all over as automatic electric lazy susan builds are regularly used by advertisers, bakers, and photographers.

Just imagine your birthday cake slowly rotating endlessly as the guests arrive for the reception or a vase surrounded by bonnie vine glasses. The usages of a portable electric lazy susan are limited only by your imagination. So, get ready to build one yourself!

Get Yours Now

Now is a good time to recall the funny idea I worked on a while back when I needed to spin a fake security camera. Due to budgetary considerations, and having some experience with microwave turntable motors, I rigged up my quick model at that time using a cheap ac synchronous motor. Although it was a rush job, and I don’t have the full breakdown of how I constructed it, you can catch a glimpse from https://www.codrey.com/electronic-circuits/how-to-modify-a- fake-dummy-cctv-camera/

As pointed out above, simply with a single-phase synchronous motor you can easily build an electric lazy susan. Note that cheap single-phase synchronous motors are available in small sizes for microwave oven, dishwasher, air conditioner and electric fan applications. The motor is in fact a heedful combination of a permanent magnet motor and a speed reduction gear assembly. Its key advantages are compact size, low power, low noise level and large output torque.

Construction of a lazy susan based on this motor is extremely easy as you need only one device to complete the build – the microwave turntable motor (single-phase synchronous motor). Only one rocker switch and a bit of twin-wire cable is needed to complete the electrical ‘engine’.

There are many ways to prepare the enclosure (you can find a way to do that). The rotating shaft of the motor has to be firmly attached (and cleverly) to the top rotating plate (turntable) of your lazy susan – the real platform onto which your object will sit.

In my experience, these motors are exceedingly silent, slow, and move with subtlety. However, it is worth noting the microwave turntable motor has a pseudo-random starting direction. The 360° direction seems to be turned back if you interrupt its power supply for a moment, then resume. It usually responds but not always, so keep going until you get desired spin direction.

An Arduino Edition

Rather than toying with a previously posted idea, I’d like to share one of my recent thoughts on the construct of an Arduino powered lazy susan shoehorned for indoor/outdoor applications.

In the above hardware setup, you can see the following parts:

  • Arduino Uno
  • L9110S Dual-Motor Driver Module
  • Brushed 5V DC Motor (hand tool motor)
  • Potentiometer 10K
  • Button Switch (N/O)

The motor driver module has two L9110S IC’s, so it can control two dc motors. The module works with voltages from 2.5 to 12V and can give a continues current of 800mA (maximum peak current 1.5-2A) more than enough for small brushed dc motors. See a good old L9110S motor driver module primer https://www.electroschematics.com/l9110-motor-driver-primer/

While starting your play with the dc motor, first off take a keen look at its technical specs to ensure that the L9110S module can work happily with your motor. Below you can see an example – key specs of a common hand tool dc motor available from web shops.

In this project we will regulate the speed of the motor using a potentiometer and change the rotation direction using a push button. As for the power supply I chose to use a well-regulated 5V dc power source. Here is the complete Arduino code of the project.

/*

 * Electric Lazy Susan

 * DC Version with Arduino Uno & L9110S Motor Driver Module

 * & 5VDC Brushed DC Motor

 * T.K.Hareendran/05-2020

 */

 

/* Warning! Do not use Arduino's onboard 5V to power the motor driver */

 

#define button   8 // Direction button input D8

#define knob     0 // Potentiometer input A0

#define chl1     9 // AI-A of motor driver output D9

#define chl2    10 // AI-B of motor driver output D10

 

boolean motor_dir = 0;

int motor_speed;

 

void setup() {

  pinMode(button, INPUT_PULLUP); //Enable internal pull-up

  pinMode(chl1,   OUTPUT);

  pinMode(chl2,   OUTPUT);

}

 

void loop() {

  motor_speed = analogRead(knob) / 4; // Potentiometer value from 0 to 255

  if(motor_dir)

    analogWrite(chl1, motor_speed);

  else

    analogWrite(chl2, motor_speed);

  if(!digitalRead(button)){                // If direction button is pressed

    while(!digitalRead(button));          // Wait until direction button released

    motor_dir = !motor_dir;              // Toggle direction variable

    if(motor_dir)

      digitalWrite(chl2, 0);

    else

      digitalWrite(chl1, 0);

  }

}


Cursory lab shots

A few caveats

  • Depending on the working voltage and the motor itself, at slower speeds the motor is not able to start and jerk with a whining sound. At the end you may need to modify this crude code (confining the speed range) to get it right
  • If the Arduino board is not plugged into a computer, there is hardly any issue in feeding stabilized 5V dc via the 5V header pin (https://www.open-electronics.org/the-power-of-arduino-this-unknown /). But do be aware that you will damage your Arduino if you have it powered through the 5V header pin and plugged into a computer. If you don’t have a clear understanding of the possible external power sources, just open the jumper to use two independent power sources – one for the Arduino as usual (USB/DC Jack) and the other for the motor driver (2.5-12V DC)
  • The L9110S IC has a rated peak current of 1.5A to 2A, however, this is good only for short bursts, and keeping it for any length of time will probably result in damage to the IC. Its maximum operating temperature is 80 ºC, and power dissipation is critical. Since the L9110S module does not have any way to dissipate the generated heat, attaching the module using its center hole to a proper heatsink plate will dispel the heat decently
  • A small dc motor runs at extremely high speed naturally has a very little torque. Although the ‘engine’ used to drive this dc motor allows decent speed regulation, a geared-dc motor seems to be a good alternate
  • The button switch does not have a resistor, it relies upon the internal pull-up enabled in the code. The internal pull-up is around 50KΩ and thus does not draw much power. However over long cable runs the pull-up may be too infirm to counter noise being picked up on the wire. Also, button switches have springy contacts, and these contacts bounce as they close. So, there are bounces instead of a smooth transition. Although software and hardware debouncing techniques can be applied to set this right, the latter is adequate in this setup. A 1uF capacitor wired in parallel with the button switch here gives us about 46ms debounce

http://ladyada.net/library/rccalc.html

https://learn.sparkfun.com/tutorials/logic-levels/all#arduino-logic-levels

Embed with Elliot: Debounce your Noisy Buttons, Part I

Now it is your turn!

I hope you will find this article interesting and maybe of some inspiration to have little fun in your lab. Of course, the ideas presented here are quite common and simple but fun to build. The mechanics are a bit difficult, and you may need some good luck with it. Try them only if you know what you are doing and do not forget to recall the risks of dangerous high voltages if involved in your models. Good luck on your 360° turntable projects!

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