I have been working on building a 1:1 scale R2D2 replica and have being trying to control it with my iPhone/iPad. The the past I have used a combination of TouchOSC and mrmr. I like that TouchOSC is bidirectional and supports custom OSC messages which lets me use a stock make controller to link buttons and controls to physical devices like lights/servos/switches etc. The make controller uses the OSC protocol as well. For example to set the position of servo 0 to 512 you would send the following to the make controller board:
TouchOSC lets me send custom OSC messages so I can do this, but unfortunately, the make controller only accepts integers and TouchOSC sends floating point numbers so the direct link doesn't quite make it.
Can I set the number type sent to be float or int on Control?
Also mrmr has a couple widget types that are useful like the text sending widget that allows you to enter something on the on screen keyboard and have that sent as an OSC message. mrmr also has a webview widget which is great for the onboard IP camera that my R2 has so I can control it remotely with a first person view.
Are you planning on adding other widget types like a webview or text widget?
You can see my controlling some servos and the R2 dome with TouchOSC here: