Hacking a SMART Response XE

The Tiny Computer of Your Dreams

Note: I'm writing this on my phone so no headers and decent lists and stuff. I'll fix it later eventually probably.

Today I learned about a portable device called the SMART Response XE. Basically, it used to be an expensive unit to let teachers answer questions because it is too hard to raise hands (OK more for testing). Now that Chromebooks exist, they are basically useless, so you can get them for insanely cheap on eBay. This device, however, is basically an Arduino. Bundle it with a 2.4GHz transceiver, a screen, and a keyboard, and you have yourself one of the most amazing little bits of kit that are basically begging to be hacked. Anyway, I bought a lot of 5 functional units on eBay as well as 2 CP2102 serial adapters and 50 5x2 pin headers on Amazon (I only wanted a couple but whatever). It also has 128K of flash(?) so I have plenty of room to play with. Some madlad wrote a support library for it so I have almost all the previous functionality except I can control everything. I want to write a little operating system for it. Here are my current ideas:

* An FTP client so it can use a file server as a storage device. The server will be mounted (in a way) and accessible through a file browser (maybe it can use this to have even more apps? 👀)

* Normal PDA functions (calendar, calculator, memos, etc.)

* A VT100 terminal to easily access Linux devices with SSH (or Telnet because its easier)

* Maybe support for a USB flash drive but I'm not totally sure how that would work (if it's even possible) as it uses quite a lot of pins. I'll look into it later.

* I dunno what else, but I can promise it will be fun. This list will become bigger tho.

Obviously this will be an open source project, so if you want to follow the development, don't forget to watch and star DremduinOS XE (it may not work currently as I havn't made the repo yet). I will probably make it available for normal Arduinos and call it just plain DremduinOS later when I'm bored.

The reason I don't make an OS for a normal Arduino is because Arduinos aren't really a good candidate to be a computer. The XE, though, makes everything be in a single case and it can be bought and hacked. This is better than having to download STL files and buying parts to try to make the exact same configuration as a list of instructions I make. This makes it much easier to make an OS.

Update (9/1/20 at 20:35): I just bought a USB controller for Arduino and it'll be here some time before the 21st. It'll be cool to try to get it to work.

Update (9/3/20 at 19:49): The USB thing isn't going to work but on the bright side I have successfully hacked an XE! It took over 6 hours due to lack of information, but thanks to the help from The Performance Whisperer (creator of the Blog post I mentioned above) I was able to pull it off. I'm not actually 100% sure that it worked but there were no errors so I will assume that it did. I'll prewire the COM port on Monday and test it on Tuesday. If it works, I'm going to write a comprehensive guide for hacking it.

Update (9/8/20 at 13:46): useful

rs232 restoration:

U3 (microcontroller) pin 47 to U6 (unpopulated) pin 11 is the TX line for the RS232 port. U3 pin 46 to U6 pin 9 is the RX lime for the RS232 port. To fix the TX line, bridge U6 pin 11 to U6 pin 8. To restore RX, bridge U6 pin 13 to U6 pin 9. Doing these actions will put TX at pad 1 and RX at pad 3, as well as restoring the RS232 port. This can then be hooked up to the CP2102 adapter. These instructions aren't great and are mainly just a memo for myself. Expect a well-written document within the week for hacking the SMART Response XE.

Update (10/7/20 at 10:42): Obviously, this project has come to a bit of a standstill and will probably be put on hold for a bit, so here's some infomations on where we're at right now:

1.) My soldering skills are trash and I failed to restore RS232 on my first board and even ripped off a pad and a random resistor. It worked but then I killed the AVR because weak ISP header connections, which brings me to the next point.

2.) I decided to switch from the RS232 approach to just programming it via the ISP pogo pins. This prevents you from having to solder to the board or even opening it at all, keeping it cosmetically the same and not have plastic bits jabbed on your hands if you try to hold it. HOWEVER,

3.) I realized that they decided it would be "Smart" to make the pogo pins not be the standard distance of 2.54 mm apart from eachother, which makes it so I can't just use the breadboard thing that I made here. I'll have to 3D print a weird breakout board type thing to get the exact measurement. I've only been able to program something once but couldn't get it to do it again due to the unreliable connection.