Peter Wallers Robot Ramblings

[Remote-Controlled Dave]

No design is unbeatable. To get the pump, drive and spinner into weight, some compromises will have to be made, whether its that the pump doesn't stick as much as it could, or its not as mobile as it could be, or the spinner is less punishing. And also, Peter always bases his suction robots on his arena floor, but is yet to make a good one to work on any surface, so that'll also be a factor. It could be that he will get the balance right and his robot will be pretty formidable, but it'll never be unbeatable. Vertical spinners managed to pop Vaccuum off the surface, even when full suction was on. I hope he gets it going to the best of his ability, to give us a new sort of challenge.

[peterwaller]

I wouldn't worry too much there are a lot of things to get correct before I get something running and there are many robots that can take a hit from a spinner without damage. Plus there are things like how long I can power both pump and spinner from what ever size battery I can get in the robot. It is a long way from being an unbeatable robot especially with me driving it.

[peterwaller]

Recieved the bits from Shapeways yesterday that was quite quick just 7 days and that was delayed by a couple of days over the weekend as they were dispatched Friday. There were a couple of problems, two of the 4 webs between the suction cup and the chassis were missing, unfortunately it was the two where the motors are so the chassis flex would reduce the pressure on the wheels. To fix this I have glued some plastic in just hope the cyno holds.

The other problem was the centre circle of the vacuum cup was not filled in giving a 2mm step where the screws for the spinner motor mount went. To fix this I had to machine up a small disc to fill it.

[peterwaller]

I have been doing some experimenting with the new smaller pump and was initially disapointed with the results.
Even with the larger suction area the downforce created was less than I had hoped and because the motors were rated at 9V the only way I could give them a bit more welly (technical term) was to go to three cells with the extra weight that entails.
I took the motor out only to find it was 12mm dia and 1mm shaft rather similar to those used in our drive motor gearboxes.
The first one I tried was an HP motor but that was drawing over 0.5A which would be a large drain on the batteries but the standard motors are less power hungry taking a maximum of 0.3A and less if you throttle back. The motor with the gear removed just fitted exactly in place although the shaft is a little short for my liking but it has further reduced the pump weight from 14.3 to 10.6 gms.
I just did a test at 7.5v it draws 0.25A and required just about 1kg pull to lift it off a shiny desk surface.
I now need to do some more work on the skirts so it can actually move and always sucks down when the pump starts.

[peterwaller]

As a biproduct of the above I bought one of the tiny solorbotics motor gearboxes with the thought of using it on the pump.
It had the power to drive the pump but with the 25:1 reduction the speed was to low.
Dispite having all the dimensions beforehand I just didn't appreciate just how small they really are and only 1.2 gms.

I feel an even lighter alsoran on the horizon.

[Remote-Controlled Dave]

I think those are the ones Scott is using in his flat fleaweight

[peterwaller]

I just had a look at Scotts picture and it looks assuming the motor is laid in the right way round that the motor is black and the gearbox metalic which is the other way round to the one I have so maybe Scott could enlighten us on that

[EpicentrE]

I'm actually using ones from gizmoszone.com, which also use 6mm motors, but have different gearboxes.

[peterwaller]

Just been playing with one of the RX31 receivers.
By adding the FET that comes with it you have a built in 2Amp contoller for the vacuum pump on the throttle channel.
This means switching the spinner controller to the rudder channel.
As left stick left/right isn't very easy to do I intend fitting a switch and pot to the TX.
The switch will be on off for the spinner and the pot will set the speed when the the switch on.
This way you can preset the best speed but still make changes if conditions vary.
Cheers Scott I hadn't seen those motors before I was thinking of making Alsorun a low wedge that could hopfully get under the opposition and strand them long enough for Combatant to attack.
Just noticed the latest RX31 receivers are rated 3-10V not 3-6V that they used to be so in theory I wouldn't need my regulator when there is no servo involved.

[peterwaller]

With all the bits included except the weapon bar/blade it comes out at 108.4gms so it is looking feasable as far as weight is concerned.
Still need to sort the grip/suction out.