So, lately I have been getting into electronics. I've gotten myself an Arduino Uno with some things to play with. I almost had my Arduino working with my jailbroken iPhone 4, which has serial RX/TX, but the phone is old and wouldn't work. For some reason I am really infatuated with the idea of controlling commercial devices with my own software and hardware, and controlling other things with those devices, so I've been looking for something cheap I can use to do that. With the iPhone you can make a serial cable to control the Arduino, or have the Arduino control software on the iPhone. I was able to do that, but since my phone was corrupt, it was rebooting every time I ended the serial connection, but that's not the focus of this thread. What I'm looking for is a handheld device that has serial (or parallel) RX and TX lines that I can write software for to control an Arduino and vice versa. I've thought about getting a used Android phone, which would be easier to work with than an iPhone on my shitty hackintoshed laptop. Another device I've looked into is the Pocket Station. It has parallel RX/TX, so I'd need a parallel-to-serial shift register, but that shouldn't be a problem. It's far more limited in functionality than an Android phone, but it would be cool to have one since not many people do and I love obscure things. I do not know of any handheld gaming devices with serial or parallel possibilities, but I don't know of any better place to ask a question like this. TL;DR What handheld computer would you recommend for interfacing with an Arduino or other similar development board via serial or parallel? I'd prefer to spend under $30, but can go no higher than $50.