Peachy Ripoff ?

http://www.3dprinterworld.com/articl...led-3d-printer

looks as though Z is controlled using a pressure transducer

more details here http://3dprint.com/7852/hardcotton-elemental/

I wouldn't quite call it a ripoff. It's more closely copying the very first 3D printer than it is the Peachy (or to be more accurate, both the Peachy and the Elemental copy that setup's method).
The main innovative feature of the Peachy isn't top-surface printing, and that's the only thing that the Hardcotton machine has in common with it.

The main Peachy innovations are analog laser position control through a sound signal, and floating the resin on saline to reduce the amount of resin needed for big prints (the former I have a feeling other printer makers are much too sceptical about to copy it yet, and the latter is adaptable to any top-surface printer, even the huge industrial ones).

Canberra? Cool, I might be able to check it out if they put it on display.

I was looking at a pressure sensor for the Peachy, but pressure sensors are expensive ($25 or so for a high-resolution one, and a lot more if you want it to handle potentially getting filled with water). Not a problem for this $1000 printer, but definitely a problem for the $100 Peachy. Alternatively you can just stick a transducer under the build container, but that's also got drawbacks (potentially a lot of weight on it, uncertain density of saline solution and resin, resin density may change as it's cured, etc).

In any case, this is hardly a competitor to the Peachy. Completely different market segments - and if they're only just getting ready for a Kickstarter campaign then I suspect they've got a long way to go on the design.