Introduction: Monster Toy Picker-Upper

About: There are some things you should just NEVER do.....

Monster Toy Picker-Upper

When its time to clean up the toys do you hear moaning and groaning..... "Do I have to?"

Well, don't have your children pick up their toys, have the Monster Toy Pickerupper gobble up their toys!

This little contraption has a multicolored tongue that spins as the monster is driven around the floor. The tongue sweeps the toys into its belly, ready to be dumped into wherever toys are stored.

Step 1: Materials and Tools


1/4" Sheet PVC, See Description for Sizes

Zinc Plated 3/16" Steel Rod, 8-5/8" long

3/4" Dia Wood Dowel, 7-3/8" long

Multicolored Sponges

1.5mm Thick Polycarbonate Sheet 180 x 190mm

3D Printed Wheels and Drive Train

3D Printed Sponge Holders

Non-Slip Shelf Liner

2 - 5/16" x 3/4" Hex Bolt and 4 Washers

4 - Washers for 3/16" Rod

2 - #6 x 3/8" Sheet Metal Screws

PVC Cement (I used the type for PVC pipe)

1 Minute Epoxy Glue

Super Glue

Hot Glue and Gun


Saw to cut PVC

Saw to cut Steel Rod

Drill Bits: 1/4", 3/16" Twist, 3/4" Paddle

Drill Motor

Razor Knife

Straight Edge


3D printer or print service

Step 2: Drive Train

The Drive Train is 3D printed. Both wheels are identical but only one wheel drives the spinning tongue. (This allows the monster to corner sharply - otherwise I'd need a differential as both wheels would be locked into the same rate of rotation - i.e. travel in a straight line.)

The wheels have internal teeth that mesh with a small spur gear on the rod that goes to the sponges.

The wheels are mounted using a 5/16" x 3/4" Hex Bolt that is screwed into a disk of PVC sheet with a 1/4" hole drilled in the center that is glued to the body. The Bolt essentially cuts threads into the PVC. Washers are applied to both sides of the wheel.

The non-driven side has a small plastic cap to capture the end of the rod (like the spur gear does on the drive side). The cap and spur gear fit snug on the rod and are held in place with super glue. Washers are provided on the drive rod on both sides of the body.

A big Thank You to Zach Hoeken who posted planetary gears on Thingiverse upon which my gear train is based:

Planetary Gears by hoeken
Published on November 8, 2008

Step 3: Tongue - the Spinning Toy 'Annihilator'

The tongue is make up of common household cellulose sponges (5/8" thick) cut to approximately 1-1/2" x 3".

The sponges are held to the drive rod by "sponge holders" (what a novel name) which are 3D printed. The sponge holder was printed upright as shown in the rendering. The 45 degree 'V' (vault) on the bottom allows it to be printed without supports. The top V is just to be symmetrical.

The sponge holders slip onto the drive rod with a washer on each end next to the body.

The sponge holders have a diamond cutout on the side. This allow the drive rod to be accessed when all the sponges are installed and for hot glue or epoxy to be applied in the diamond to fix the sponge holder to the rod so it does not slip.

Step 4: The Body - a Box-ish Thing

The body is made from 1/4" PVC (foamed) sheet. It really was quite easy to work with and did not require any painting to finish the project. It went together pretty easy and using PVC pipe cement worked well with set up to allow handling in about 15 minutes.

The body is composed of the following:

(Refer to the labels on the photos to identify the components)

[I have been working a lot with the metric system since I have been working with 3D printing and so I cut out my panels measured in millimeters - Sorry if that causes anyone some grief.]

Left and Right Side Panels (identical) 200 x 350mm

Rear Panel 185 x 190mm

Front and Rear Handle Panel (identical) 185 x 70mm at peak (30 mm straight side)

Toy Tray Bottom 185 x 205mm

Bottom Plate 185 x 260mm

Front Panel 200 x 242mm at peak (200mm straight side)

Step 5: Handle and TEETH - the Better to Eat You With....

I thought a nice wood dowel would make a great handle. It is fastened between the Front Handle Panel and Rear Handle Panel; the two panels that make up a toy tray to collect toys that escape the 'Monster'.

The 3/4" diameter dowel fits snuggly between the two panels and is captured by two rings made of 1/4" PVC sheet. The rings are just pieces of 1/4" PVC sheet with holes drilled in them with a 3/4" paddle bit. The rings are slipped over the dowel and the dowel is slipped into place and the rings are glued in place.

Since this was a monster I thought it should be a bit menacing looking. I chose to give it a bunch of pointy teeth. I just marked out the tooth pattern on the Front Panel (face) and cut them out with a bandsaw.

Step 6: Wheel Tread - for All Terrain Use

The 3D printed wheels are smooth so they needed to be modified to allow them to grip both carpet and smooth floors (i.e., tile and hardwood). I decided that a simple fix was to take some nonslip shelf liner and to cut long thin strips of it and glue it to the perimeter of the wheels.

I took a straight edge and a razor knife and using an old cardboard box as a cutting board sliced thin strips of the rubbery liner. I then used epoxy glue to fasten them around the wheels. I used kind of a crazy method to do this - I ran a bead of epoxy down a piece of cardboard and then rolled the wheel down the epoxy coating the circumference. I then placed the thin strip of liner on the 'wet' wheel. The liner was almost the right length to go completely around - I only had to add a small 1/4" segment to fill a gap.

Step 7: Scoop - the Fix?

My initial design kept having toys get jammed between the sponges and the bottom plate (cut at 45 degrees). I couldn't really have the bottom plate any closer to the floor or it might drag and the wheels might not contact the floor properly if they sunk into carpet.

I decided to add a scoop of polycarbonate to ride with the floor level. The scoop is 1.5mm polycarbonate 180 x 190mm.

It has a slight downward bend in it so it contacts the floor. It is fastened loosely at the rear by two screws that allow it vertical play. I decided to bend the sheet and clamped each half in wood strips with a gap between where I wanted the bend to occur. I used some aluminum foil to provide a head shield for may spring clamps.

After some patient heating the plastic started to slump and I got the bend I wanted. Drilled two mounting holes at the far end of the sheet and mounted it to the bottom plate with two #6 x 3/8" Sheet Metal Screws. I kept the screws loose so that the sheet can ride up and down and so the tips of the screws don't poke through the bottom plate.

My 'fix' had limited success.....

Step 8: Full Disclosure....

Well, My Monster Toy Picker-Upper is not so hungry. Its not eating.

As noted in step 7 the toys kept getting caught on the bottom of the unit and on the polycarbonate sheet that was added to correct the problem. So I would say that even though the concept was neat and the 'monster' looked cute - it did not work well... really, not at all. :-(

Some lessons learned:

1. It appears that the sponges need to be longer or more flexible so that if on first contact the toy does not go in the 'sponge' or new flap thingie will flip over it and not jam it into the bottom of the unit. Presently the sponges will pin the toy against the bottom plate or polycarbonate sheet and stop the tongue from spinning.

2. The drive train needs to be more robust, or at least fine tuned so that is runs smoothly. 3D printed gears work, but may hang occasionally - sometimes here too. They run well, but every so often they hang. That may have to do with how well the wheels are running true on the axial. The wheel mounting is OK, but could be better. If I thought that the 'monster' was going to get excessive use I would probably explore real bearings.

3. I had fun designing and printing the 'sponge holders'. I got more experience with Fusion 360 and 3D printing in general. They turned out well and did exactly what I intended.

4. PVC sheet material is nice to work with. I found it at Home Depot for $15 for a 2' x 4' sheet of 1/4" thick. It allows use of woodworking tools and it glues fast with PVC cement and does not need to be painted. I'll have to use it in some future projects.

5. Nonslip drawer liners work well on 3D printed wheels. This combination worked surprisingly well. The wheels did not slip on hard floors or carpet. There were easy to put together too.

So the concept is nice but probably needs some additional experimentation and redesign to get it functioning correctly. I still had fun making this instructable and learned a few things! Hopefully you did too.

Thanks for reading!

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