Senior year has started and it is finally ready to dive into my senior project. It is daunting to think that I now have to actually apply all that I just had to write in a report last school year, but I’m not here to just write stuff down. The project will surely be difficult but I look forward to all the challenges it holds in store for me. My first steps are to decide exactly where to step first, detailed below.
Starting Point:
Decide which path to take. The abstract idea of my project, using a drone to relay a signal from one point to another, is simple. Deciding how to do it is not. There are many different paths that I could take to accomplish this. Normally I would pick one path, but I have decided that approaching the problem from two paths at more-or-less the same time may be a better way to go about it.
Path 1: The simple path. This will be the best way for me to jump right in and get something working as soon as possible, as suggested by my adviser, John Spinelli. The quicker I can see the project start to take shape, or NOT take shape due to roadblocks, the better. For this path, I will use very simple receivers and transmitters, all off-the-shelf with as little modifications as possible needed. To start I will also focus on ground testing with no drone, just a stand-in.
- Ground Station:
- RC transmitter for control (have my own for testing in the short term)
- Video transmitter (have my own for testing in the short term)
- Relay stand-in:
- RC receiver (have my own for testing in the short term)
- RC transmitter module
- Video receiver
- Video transmitter
- Remote station/plane stand-in:
- RC receiver (have my own for testing in the short term)
- Video receiver (have my own for testing in the short term)
The hope is that most of these components can be connected/bound together easily. The biggest unknown is connecting the RC receiver to the transmitter module. I am fairly sure that the RC transmitter module receives info by PPM. A microcontroller will likely be needed to take the SBUS output of the RC receiver and pipe it into the transmitter module as PPM.
Connecting the analog video transmitter and receiver together should be as simple as wiring the video-out of the receiver into the video-in of the transmitter, but I am not fully confident of that so it will take some experimenting.
Path 2: The more complex path. This path will require me to aggregate the video and control signals onto my own signal. The two endpoints, the ground station and the remote station, will have their control and video tx/rxs plugged into a “box” that takes the two signals, digitizes them (or would it?), and then sends/receives one signal to the relay. The relay now only has to deal with relaying one signal rather than two (or three, if telemetry is included eventually).
The only solution that comes to mind is using XBee radios as the senior Aero team has used them in the past for telemetry. After a cursory glance at their product catalog, a module like this may be suitable. 250kbps may be enough for low quality video along with control and telemetry data. The modules are expensive though, so further research is needed into their suitability and other alternatives.
The benefit of this solution, regardless of the implementation, is the flexibility and additional learning opportunities. I now have the freedom to pick the frequency, power, protocol, and many other aspects of how the data actually gets relayed.
All in all, pursuing both of these paths will allow me to get a prototype up and running as quickly as possible, as well as start the process of creating a more custom and featured solution that allows additional learning opportunities.
Other To-Do’s:
- Test lifting capacity of current drone.
- Need to wait for rain to clear up as well as purchase a new LiPo that is of better (lower) capacity so more carrying capacity is available.
- Draft an SRG to submit for the Sept. 20th funding round.
- Testing metrics. Most are already in my report but I will look over them again and add/remove/modify.