High loadable turntable

[WalterMo]

This turntable is the Goliath among the other tables which I had posted before:
viewtopic.php?f=6&t=2383
viewtopic.php?f=6&t=4291

It can withstand loads up to 200kg (per producer). But I never have tested the table with such high loads, only up to about 20kg. The (static) load is one thing, the other is that the mass also must be acceletated (against the inertia). Therefore I have implemented acceleration and deceleration ramps of the stepper motor speed.

The gear ring and its carrier ring are mounted together to one device. They are made of a very stable plastic. The upper ring is mechanically assisted by a lot of steel balls:

http://www.ebay.de/itm/Kugellenkkranz-L ... 43c73a7e13

The stepper motor with a planetary gear came from here:
http://nodna.de/nema-17-planetary-518-1-stepper-motor

The black plastic box for the motor is this:
http://www.conrad.de/ce/de/product/5384 ... 1GSBK-1-St

A cogwheel (it comes with the rings unit) is mounted at the gear's output shaft to drive the gear ring. An advantage is that the motor is lying horizontally, so the total height of the device is rather low.

Dimensions: Diameter of the platter: 280mm, overall height: 63mm.
Further specifications:
gear ring: 139 cogs
pinion: 24 cogs
gear ratio ( table gear ring / pinion): 5.79 / 1
gear ratio (motor / planetary gear): 5.1818 / 1
motor driver board: Pololu A4988 (¼ micro step mode)
platter: aluminium, 5mm thick
square plate: 300 x 300 mm, aluminium, 5mm thick
controller: Arduino Uno
power supply: 9V wall wart

Walter

[JDM Dyno]

looks very good Walter


be interesting to see how much It will take without stripping the plastic gears

I've done this one and tested with over 70 kg, turns ok but need a lower gearing to stop it wobbling when it stops turning, only 2:1 at the moment, I was going to put acceleration and deceleration on to help to.

its a bit ruff at the moment but just testing with things I have already, mostly scrap

[hunkatibor2]

Hi Walter
Worthy, precise and beautiful solution.
Tibor

[Jokeri]

Hello Waltermo!

Can you share the code please!

I wish that you posted this sooner!



Thanks,
TT

[WalterMo]

The controller hardware (circuit diagram) is very similar to this:
download/file.php?id=6825&mode=view
I forgot to draw in two 1kOhm resistors. Each from the input pins 6 and 7 of the Arduino to 5 Volts. The resistor R3 is optional, for details see my first post here:
viewtopic.php?f=6&t=4291

Only the inputs MS1 and MS2 of the Pololu for micro stepping are a bit different. Means the switch for MS1 = off and for MS2 = on. Don't forget to glue a small heatsink on the Pololu IC. And add a little fan if necessary.
And here is the code:

Edit: Version Leo3_3 doesn't need the two mentioned above resistors. Regarding resistors: There are only 2 resistors at the angle increment switch necessary. See the attached circuit diagram.

[WalterMo]

[micr0]

Thanks WalterMo.

I've been building a 2ax trunnion that is big enough to hold engine parts for scanning. I'm waiting on the second stepper and drive, and to finish the control panel design, but here are a few pictures of my current progress. I designed to be easily disassembled and laid flat in a storage case.

µ

Youtube video:

[JDM Dyno]

looking really good micr0

was thinking of something like that myself https://www.youtube.com/watch?v=HfuM0xw ... DA9BA6D3A5

check out this video to, at about 3 minuets it gives the price

https://www.youtube.com/watch?v=4AypqqyBTWg

[WalterMo]

For those who need a more powerful stepping motor driver board.

Here it is. It has the Toshiba-IC TB6560 AHQ on board which can drive a peak current up to 3.5 A per motor phase. It's coming from China but you can also buy it in Berlin, Germany:
http://www.ebay.de/itm/SainSmart-CNC-Ro ... AQ:DE:1123

Maybe it's even possible to beat down its price. Anyway they offer a price proposal.

It is easy to use, similar to the Pololu A4988. But it has some more features which can simply be adjusted by mini switches. And it is mounted on a sufficiently big heatsink.
Unfortunately it doesn't has the possibility to choose 1/4 step mode, only 1/1, 1/2, 1/8 and 1/16. I mention this because my Arduino code 'Turntable_Leo3_3' some posts above was programmed for 1/4 step mode.

[ThomasSc]

[micr0]

[WalterMo]

Hi micr0,

3 years ago I had built a 2 axis positioner:
viewtopic.php?f=6&t=4154

Maybe you can take some ideas from the design/code. There are 2 pins free on the Arduino Uno for your special modification.

I have just looked on ThomasSc's design and code (2 posts above). He is already using the powerful motor driver from SainSmart. And I thought I would be the very first user/pioneer on this forum.

Thomas has used an elegant way to program the code. Simply by calling up the Arduino pre-built library 'AccelStepper'. I didn't know it before.
This subroutine contains already accelelation and deceleration for the motor speed.

Walter

[micr0]

[micr0]

[JDM Dyno]

like the panel very cool

I have a 128 x 64 lcd that I am going to use if I get time, already done an ECU display with one and a Haldex controller with another with arduino