Loading

Heavy Duty Lazy Susan for Full Body Scanning

by fredini, published

Heavy Duty Lazy Susan for Full Body Scanning by fredini Aug 23, 2012

Featured Thing!

Description

Coney Island Scan-A-Rama:
------------------------------------
A 3D scanning turntable capable of supporting the weight of a human being. Since discovering ReconstructMe, I've been looking for a suitable turntable setup for creating full body scans of people. Most of the plans out there are for tabletop photo or scanning setups that won't handle a lot of weight.

Lo and behold, I found these plans cheesycam.com/motorized-lazy-susan-heavy-duty/, for using the
front wheel hub assembly from a car as the rotation bearing and an electric drill to power turning it. My implementation can be built for around $100.

This device is the centerpiece of my Coney Island Scan-A-Rama Project- a next generation photo booth in which subjects are scanned and printed.

Update 10/16/2012
------------------------
I have added a 12volt 4RPM high torque rotisserie motor with a 3D printed pulley driving a bicycle inner tube belt drive. I just uploaded images of the motor (got it on ebay), the updated assembly, as well as source files for my pulley print, with slots for a set screw and nut.

Update 7/21/2013
-----------------------
Added a new pulley in two parts that can be printed on a Replicator build platform, then glued afterwards. Drill afterwards to use a setscrew through a bolt in the slot against the flattened part of the motor shaft.

Update 8/3/2013
-----------------------
I have also added a foot pedal to apply power to the turntable motor. However, I am seeking advice for a braking mechanism for the wheel when power is not applied. I was thinking a solenoid or something that could retract as power is on. I have safety concerns for the wheel spinning as people climb on or off the wheel. Any thoughts on this are appreciated.

Recent Comments

view all
I'd like to have at least 2 people on the platform. What size diameter do you think the table surface can be extended beyond 28" and still be safe? Thanks for posting this design online BTW
Hi- Sorry for the delayed response. I use a motor like this ebay.com/itm/Electrical-Appliances-4RPM-Ouput-Speed-DC-Geared-Motor-/271243349319?pt=LH_DefaultDomain_0&;hash=item3f275d0d47 with a standard 12v wall wart power transformer and a foot pedal to activate/deactivate the rotation. Hope this helps.
What was your final solution to this? I have recently built the table and have all other parts, but not sure how to power the motor now. Emailed Fredini, but hoping you will see this message also.

More from 3D Printer Accessories

view more

Makes

Liked By

view all

Tags

Give a Shout Out

If you print this Thing and display it in public proudly give attribution by printing and displaying this tag. Print Thing Tag

Instructions

See the Make Magazine build instructions here:
makezine.com/projects/guide-to-3d-printing-2014/heavy-duty-turntable/

Parts needed:
-Front Hub Assembly from car (~$30 on Ebay)
-2x 28" plywood circles (top plates)
-1x 12" plywood circle (Inner part for belt drive pulley)
-1x 14" plywood circle (outer part for belt drive pulley)
-1x 28" plywood square (base)
-10" plywood square
-some 2x4 and plywood scraps
-6x 3 1/2" x 3/8" carriage bolts
-3x 3"x 1/2" lag bolts
-Fender washers
-old bike tire tubes for the belt to power the turntable
-12 volt 4 RPM high torque rotisserie motor
-hose clamps
- Foot Switch (such as harborfreight.com/power-maintained-foot-switch-96618.html)
-Extension cord


Steps:
1) Using a router or jigsaw, cut out the circles from a sheet of 3/4" plywood.
2) Next, cut inner circles out of the center of both squares and the 12 and 14" circles. This gives a place for the center of the hub assembly to recess into so that it can be bolted onto the plywood.
3) After placing the hub, mark the wood and drill holes for the bolts.
4) Bolt the hub to the base. Add 2x4 blocks to the corners of the base as feet.
5) Bolt the top turntable to the top of the hub. The order the circles stack is 14", 12", 28" 28". This creates a pulley to power turning the platform and a double layer of plywood on top for people to stand on.
6) Mount the rotisserie motor with the printed gear on a 2x4. Put the bike tube around the pulley under the turntable, and stretch it around the pulley on the motor. Screw the 2x4 to the base so that the belt is stretched tight.

Now get someone to stand on it, fire up ReconstructMe, and start scanning with the human highres setting!
I'd like to have at least 2 people on the platform. What size diameter do you think the table surface can be extended beyond 28" and still be safe? Thanks for posting this design online BTW
Great design Fredini, thanks for sharing it, I have built one based on your design and just need to to add the motor. I have a 12v rotisserie motor from China but am wondering what kind of power supply to hook it up too, i.e how many watts will it need to turn up to 3 folk around? Look forward to seeing your brake design too.
What was your final solution to this? I have recently built the table and have all other parts, but not sure how to power the motor now. Emailed Fredini, but hoping you will see this message also.
Hi- Sorry for the delayed response. I use a motor like this ebay.com/itm/Electrical-Appliances-4RPM-Ouput-Speed-DC-Geared-Motor-/271243349319?pt=LH_DefaultDomain_0&;hash=item3f275d0d47 with a standard 12v wall wart power transformer and a foot pedal to activate/deactivate the rotation. Hope this helps.
I was going to suggest using the turntable motor for braking by having a N.C. (normally closed) relay wired to it in order to short the motor leads together when the motor is deactivated. Should work for DC motors. But I think I am too late.....you already built the brake.
Go to Amazon, type in 'lazy susan bearing', do not pass go, do not collect $200,
Far more suitable 1000 pound 12" bearing for $16.25.
I totally disagree that that is better than my solution of the car hub. Uneven weight on the turntable would destroy those bearings. My solution allows up to four people to pose together with little concern for evenness of weight distribution.
About your Design..You can put Simple Wood break under the first spinning wheel..Pull and push mechanism..
Yes, I have added a brake- I need to update the project to reflect this. A simple foot pedal bar of wood on a hinge that applies pressure on the wheel from below as the subject climbs on and off. I will add some images ASAP.
I'd be interested in seeing those pictures from the brake you added, please.
Well its been awhile since you released this so have you got yourself the perfect RPM yet? If you would do everything over would you use 4 or 6 RPM? I'm building something like this for a school and I am about to purchase a 115volt gear motor for the project.
Jason,
I'm at 3rpm and have a second rig underway that I have a 4rpm motor for. I'm thinking 6rpm may be too fast, but look forward to any feedback. I have added a brake pedal that applies pressure to the underside of the wheel as people climb on and off as well- need to update the project with this. For the 2.0 version I'm thinking that the underside should have a sprocket and a chain drive with a stepper motor. Looking into this now. please let me what you get for a motor and send me some pix.
If you were to use a hub for a vehicle with ABS it would have machined teeth that you use with your solenoid for locking the rotation, just a thought
hello fredini! nice scans and scanner rig!
worm drives are auto-braking. also they are reductors, so could help with the torque too...
Can you recommend an affordable worm drive I should look at? I'm open to suggestions!
Here is an idea, use the mcmaster style lazy susan bearing and mount high quality rollers or casters around the outside of the disk to keep it level and compensate for the small diameter of the McMaster bearing. The drive motor could be housed inside the base. Here are some screenshots from a rendering I just did of this idea. I have not tried to build it yet. The number of rollers would be based on their load rating. The wheel on the motor would be sized to generate the desired RPM of the stage based on motor speed and inside circumference of surface the drive wheel bears on. Foot petal or simple on off switch to control motor.

Here is a photo album on Google+, you should be able to see it with this link:

plus.google.com/photos/110626920153939592892/albums/5910633069177318481?authkey=CIjOtPW7_6akuwE

Do you think this would work?
I would consider this approach with a subsequent turntable, but my initial experiments with these bearings showed that they didn't do too well with uneven weight distribution. Using the bearing in the center and rollers on the sides is a better solution, but with a lot of weight on the rollers I just don't know how it would spin.

The beauty of the car tire hub is that it spins very easily even with a lot of weight. The only issue is that there's a danger of it spinning out from under someone as they climb on or off. I'm much more inclined to implement a foot pedal for the operator to step on as users mount/dismount and just keep iterating on what I've got.
Hi, I'm working on an update to the project and am looking for advice on a braking mechanism for the wheel when power is not applied to the motor. There is a safety concern as people climb on and off of the wheel and there needs to be a foolproof braking mechanism so it doesn't spin out from under someone as they mount or dismount it. Any advice is appreciated!

I am considering some kind of retracting solenoid that could apply pressure from underneath when no power is on, then retract when power is applied. Any thoughts on the matter are welcome.
Does it rotate back to the exact same position at completion of scan? If so I think I have a solution for this.
No, it stops in an arbitrary position.
Really kool dude. I am kinda interested in your reconstructme software as well. Do you find it easy to use?
Since I'm a Mac guy, it was a pain to get Windows installed under boot camp and get AT
&
amp;T the right drivers to run ReMe, but after that's over it's pretty easy going.
I've considered making one of these before, but my problem with moving a person around is they might stumble. Wouldn't it be a better idea to keep them stationary and move the camera around them?
As long as the turntable moves slowly, I think this is a non issue. Moving the camera wold create issues with twisted wires and enlarge the footprint needed to work within.
Awesome project!!

This should drastically reduce the price:
http://www.mcmaster.com/#6031K18

It's a turntable that you can buy from McMaster Carr for about $4. It's got a 500 lb max capacity, so it should all but the heaviest of subjects!

You may also be able to do away with the pulley system by using a rubber wh
eel on the shaft of a motor like one of these:
http://www.ebay.com/sch/i.html?_nkw=37mm+12v+dc+4rpm+motor

Just orient the motor vertically, and put the wheel in direct contact with the edge of the turntable platform!
I've used the lazy-susan type bearings similar to the McMaster link you provided. I can attest that standing on it can result in some clunky movements if the weight is not evenly distributed. However, in my applications, the objects were large, but not heavy and the bearings worked great. Picked them up from Home Depot for about $10.
I looked at these bearings at McMaster-Carr but in my past experience with these bearings, if the weight is unevenly distributed they will not spin well. With the larger platform size IMHO, I don't think this will work well, but I'd love to be proven wrong.

If you watch the video cheesycam.com/motorized-lazy-susan-heavy-duty/ , you'll see that the larger pulley underneath makes it a lot easier to spin, as opposed to a motor attached directly to the shaft. The rubber wheel approach could be good as well. I'm thinking a stepper motor with a pull
ey may be the easiest implementation, as opposed to having to mount the motor under the platform.
This looks great! Can't wait to try it out.
one cheap motor alternative.

get a motor from a rotisserie (i see these at garage sales a bit)

they have low rpm and High torque and usually are powered from AC outlet.
I have two thoughts about where to go with the motor:

1) Stepper motor with a pulley. Once the table is turned on, this should just start the table slowly turning so the scanner could start at the bottom and work their way up the subject.

2) I was thinking about a sewing machine motor and a foot pedal. I think that a foot pedal would be a good cont
rol for the person scanning to be able to rotate the table, but maybe a continuous turn would be easier so the scanner person doesn't have to do too much at once.

So far I think #1 is the way to go. I'm curious about trying one of those rotisserie motors- that could be good if there are speed cont
rols for those.
Rotisserie motor has low RPM (uses gears for strong torque)

I would bet like a sewing machine motor, you could use

a high curent resistor (rheostat) like a dimmer switch.

the reason i would lean towards the rotisserie is it is

a simple drive that wouldn't need much in the way to control it.

a quick look on ebay and amazon showed they can had for as low as
~= $20. i saw a heavy duty one for roughly $50.
so that and a dimmer and you have a variable speed high torque solution.
for under 40 at the low end.
Thanks. I will give this a try. I think a constant rotation, low rpm motor that won't trip up the subject is the way to go. My methodology once I start has beet to do a quick up and down movement to confirm the subject was fully inside the scan area, then I start at the bottom and move upwards, ending with the face and top of the head.

Going the opposite direction I often ended up having bad geometry around the ankles.
Top