If you have an android tablet the GCodeTouch3D App might be good for your kids. https://play.google.com/store/apps/details?id=de.dietzm.gcodetouch3d Please note that the App is still in beta test, but it works fine on my printer.
Hi, I have developed GCode Simulator & Printer App for Android which allows one to use a tablet/phone with USB-OTG support to control your printer. Printing from a Galaxy Tab 2 on my Reprap printer with Sprinter/Marlin firmware works great, but I don't know if it works on Ulitmaker printers. It would be great if Ulitmaker owners could test the GCode Simulator (Free) App and provide feedback. Find more info on http://www.dietzm.de/gcodesim Thanks in advance !