Peter Wallers Robot Ramblings

[peterwaller]

I have added 1mm polycarb to the two side pods and along the front below the flipper mounted on foam double sided tape to give some impact absorption.
I have increased the thickness of the flipper face by 1mm and added a moulded panel using the tyre compound to help stop the opposition sliding off as you try to flip them.
It now comes out at 130 gms so I can either add ballast or I could run it with Alsoran as a cluster.

Here it is in action:
https://youtu.be/XsG_3un7vdQ

[peterwaller]

I mantioned the problem I had sticking PLA together well I had a chat in 3D Print World and they recommend dichloromethane which is a solvent that will weld it together.
I have ordered some from ebay I will let yo know how well it works.

[earthwormjim]

I mantioned the problem I had sticking PLA together well I had a chat in 3D Print World and they recommend dichloromethane which is a solvent that will weld it together.
I have ordered some from ebay I will let yo know how well it works.

Hi Peter. I bought some Tetrahydrofuran (THF) for use with PLA parts, but it was not very effective at all. It would be very interesting to know how the dichloromethane works as a smoother for PLA parts too!
Thanks.

[peterwaller]

The dichloromethane seems to work well as a solvent to weld two parts of PLA together but a quick try as a surface smoother didn't seem to work.
Having said that I just put the part in a jar on a block of wood about an inch above the solvent and then warmed the jar with hot water.
This works for ABS and Acetone.
As with most things these days there a quite a few warnings on the bottle including:
Irritating to eyes, respiratory system and skin.
Limited evidence of carcinogenic effects.
Vapour may cause drowsiness or dizziness

[peterwaller]

I decided to do a few tweks to my new flipper as I might as well have better armour than spare weight.
The front and sides of the chassis have been increased from 1mm PLA to 2mm and 1 mm Polycarb added on top.
Also tried to create a scoop that doesn't need a plastic sheet adding.
It is now up to 149gms and is a very tight fit in the cube.

[peterwaller]

Oops wrong picture that was the one with the blade cover on.
Here is the new scoop.

[earthwormjim]

Looks good Peter, will be interesting to see how effective the concept will be.
The second pic is definitely more likely to get under another robot! LOL!
It is difficult to see what you have done in the pic Peter. But the sheet looks as if it is mounted under the chassis??

[peterwaller]

The metal scoop is a couple of floor scraper blades side by side and shaped at the ends.
I have tried these before, without success, the secret seems to be getting the angle exactly right.
Too steep and the blade keeps digging in and too shallow and the edge is lifted off the arena surface.
The underside of the chassis has a recess for the blades and a further piece of PLA is bonded on top.
The step between the blade and the polcarb armour is filled with plastic padding.
Here is a better shot from underneath with a spare blade next to it.

It does make the robot a bit dangerous to handle hence the cover (Rule 2K) so I shall try and ensure only I retrieve it from the arena.
Out of interest how long have we had a spell checker on here I finally gave up on Internet Explorer and changed to Chrome and it appeared.

[peterwaller]

I have decided to have another go at a kinetic flipper although I have failed several times before.
So far I have come up with this.
The light blue shows the normal static position.
The brushless spins continuously and when the release catch is rotated by a servo the rubber band causes the drive cam to rotate anticlockwise until the cam engages with the rubber sleeve which should then drive the cam rapidly until it reaches the other end of the cut out where it disengages.
The cam will stop when it hits the bottom end of the catch which will then be rotated back to the original position allowing the cam to return to its start position.
I still need to work out a way to connect the cam to the flipper but it is starting to look possible.

[Rapidrory]

Glad to see this concept getting resurrected again

The thing I thought when I had a look at this idea a while back is that ideally there should be some amount of gearing between the brushless and the flipper. In this kind of setup, it would be good to have some gearing after the clutch since the friction drive system is good at transferring speed but not so good for torque, although it wouldn't really work with the cam system you have. I just feel the high speed of a brushless flywheel is difficult to translate directly to the high torque and relatively low speed of a flipper arm without something breaking or some gearing..