Unfortunately, real life has gotten in the way of my MINDSTORMS pursuits. That being said, in honor of the fact that it is summer, I have decided to take a far more structured approach to a much larger project. I won't get into it in depth here, but I essentially want to make a garden robot. That is a bit broad. To narrow it down, I have some specifications:
- Use LEGO MINDSTORMS NXT for actuation.
- Completely autonomous/maintenance-free for extended periods.
- Water plants (only, for now).
- Relay critical information over the internet (moisture content, PH levels, ambient light, etc.).
- Be completely controllable over the internet (all functions accessible).
Numbers 4 and 5, particularly considering specification 1, are apparently quite complicated. The NXT, unlike the EV3, has no embedded WiFi capability. Thankfully, with a bit of digging, I was able to chance upon two different projects:
The folks at MonoBrick have created a set of tools to allow for enhanced communication with the NXT and EV3. Notably, they have developed a "tunnel" Android application that allows you to connect the phone via bluetooth to the NXT and via the internet to a client. Using their handy C# communication library, you can develop programs to send direct commands to the NXT. Another huge plus is the capability to stream live video from the phone's camera. For the time being, this is my method of choice, but there are a couple drawbacks:
- Whatever you have running the program on (which for now is my laptop) has to be working...at all times. Considering I'm a student, this is impractical. Therefore, whatever code I write on this has to be in addition to the autonomous code that is running on the robot. This isn't a bad thing, but it will require a bit of creativity to get the two different languages to work with each other seamlessly.
- The tunnel app, after upgrading my phone to Android 5.0.2, seems to have lost its menu. This is an issue if I want to adjust anything, such as which NXT the bluetooth connection pairs with.
- I don't really understand this part, but I think that if I switch WiFi networks, I have to reconfigure the client listening port. Not a big issue, but certainly a limitation due to my restricted programming knowledge.
Secondly, I found another project by SmartLab that does something similar - you place an Android phone on the robot, and it connects via Bluetooth to the robot and via WiFi to the internet. But this one has a very different type of flexibility - the phone runs its own HTTP server, allowing you to access and control the machine via a webpage. This is exciting because it removes the need to use a local program to access the robot over the internet. But for now, this is not my method of choice for two simple reasons:
- It's written in Java. I don't know Java. At all.
- The program they used as an example works by sending direct commands to the NXT. Considering I have specified that the robot to be autonomous, I will need to figure out how I can write it as a predetermined program on the phone. I'm sure it's possible, but we are entering the realm of app development here, and I don't know anyone who develops Android apps who might be able to help me with this.
So, for the time being, while I am working out prototypes and proof-of concepts, I have decided to do as follows:
- Write a NXC program (this I've dabbled in before) that runs on the NXT to control autonomous function.
- Experiment with the MonoBrick library in VisualStudio to work out a communication method between the Windows Form application I'm planning to write (for the GUI) and the robot's data logs.
- See if I can work out streaming video (it works in MonoBrick's remote program...I should be able to get it to work on mine too! Right?)
- For all of this, use haphazardly-designed prototypes (Okay, maybe not completely) to make sure I can actually build this thing mechanically.
