Looks excellent Simon.
I think I must've missed when those little speed controllers appeared on the scene. Do you have a link to where they can be ordered?
Thanks
The fingertechs are the smallest controllers you can get. Trimmed down to their minimum they can be less than 2g each. Scott had plans to use them in a number of his robots due to their size. Only issues I saw what the amp rating, I wasn't sure if it would handle 4 motors (Simon has disproved that) and they were very expensive last I looked.
It is difficult for me to comment on these without sounding like I am trying to promote my controllers but here goes anyway as I think people might find they don't do what is expected.
These fingertechrobotics are rated at 1 A continuous and 2.8 A peak which is slightly less than the drive chip I use which is 1.2A and 3.2A so I would not recomend them for 4 HP motors.
Also the BEC is rated at only 100ma and that reduces to 40ma at 12v so only suitible for a receiver not a weapon servo.
I think part of the problem is that people just talk about two or four motors where motors vary quite dramatically.
The standard Pololu motors have a stall current of 360 ma at 6v so that is 720ma at 12v and 1.44 A for two at 12v so taking into account the liklyhood of stalling you would probably be ok with them.
The HP Pololu motors have a stall current of 1.6A at 6v so 3.2A at 12v and 6.4A for two motors at 12v so much more likely to fail.
I hope this helps.