Mounts for GPS or Cell Phones

[Ebuddy]

I've been scouring Amazon and Ebay and I've seen a few different options for mounting a cell phone or GPS unit (in a waterproof case), but none seem to be applicable to my MC-54-250 (Jonway YY250T). Either they mount on the handlebars (where I don't seem to have any extra room) or they're designed more for a motorcycle. I don't have a whole lot of space. I was wondering if anyone here had some ideas before I try to MacGuyver something.

Currently I have a TomTom One that I can use. I'd be happy to use my cell phone, but I need to be 1000% sure it won't vibrate off or get wet in the rain.