What should a pendant look like?

[EddyCurrent]

What about including a control like this ?

http://www.3dconnexion.co.uk/product...ewireless.html

I don't care too much for this one but it's got to be said, a smartphone app, probably already exists ?

[TonyD]

I started out with one of these: http://www.ebay.co.uk/itm/4-Axis-CNC...item3ce214d1eb

I had it before the machine was working and I thought it would suffice, it didnt.

I subsequently bought one of these, http://www.ebay.co.uk/itm/CNC-3-Axis...item19f0b5cf65

And while I know you're looking for design advice rather than purchase advice I posted this becuase without a doubt the most useful feature of the pendant I use now is the encoder wheel. It simply allows me great control of the machine from anywhere around the machine and allows me one thumb on the estop at the same time. I opted for the wired model becuase I didnt want to trust anything safety critical to wireless, my choice however and I'm not saying it should be that way for everyone, the long cable to be honest is a bit of a pain but I can live with it. Its not a total loss though, my four year old had the old pendant now and thinks its his phone :)

In terms of other benefits, having watched the machine rack itself just a little during construction I now watch the X axis screws like a hawk and find thats easier to do from in front of the machine which the pendant allows.