WOW!! Nice summary, thanks!
Well done getting the blog started too. That will be an excellent source of inspiration and technical info. I’ll be sure to bookmark that!
I’m in Scotland which kinda makes it hard to launch a small boat as there are islands between me and the Atlantic so it is more likely to run aground. I think I’ll have to throw it in the water on the East coast and go up and round the top.
You are way ahead of me as mine is currently a thought experiment! It is also a hobby so I’m trying to do this on as small a budget as possible.
I have broken the project up into several areas and I’m taking copious notes for each in Evernote.
As I said, my thoughts so far are:
Torpedo style hull for strength and stability. I thought long and hard about the hull shape. It needs to be strong and buoyant, and low to the sea so it doesn’t catch the wind too much, so I thought of semi-submersible. I thought this team came up with a good idea, so I was going to try a variation of this. I discovered how expensive a boat hull is to buy, so I thought a large piece if PVC pipe is going to be much cheaper and stronger too. Having talked to folk on RC boat forums, salt water and moving parts don’t mix and they have told me at length about how short a time any electrical motor will last in the sea. This will need some thought!
Solar recharging to replenish the batteries. I’ve never had much joy with solar power or electrical things, so this needs a lot of work!
I just assumed I’d use a Pi for on-board brains as I’ve used one before. I like the Grove sensors as it means I can add lots of different sensors quickly and easily. I have some worries about navigation and coast avoidance. I would clearly have to set waypoints for the vessel to track a path around the world, but I’m concerned if it drifts off course either in a current or when the batteries run out and it is charging. The concern is that the boat drifts towards shore or wakes up in a location where there is land between it’s current location and the next waypoint. It would have to have an navigation override which would prioritise avoiding land rather than getting to the next waypoint. I did post this enquiry regarding using Dijkstra’s path planning but as yet there is no reply.
I had originally thought I could use The Things Network Community LoraWAN gateways as a way of getting data back from the boat on it’s travels. It would be free to connect to a gateway and send small packets. I didn’t really want to go down the expensive satellite communications path. Having posted in their form, it looks like this was slightly optimistic. I had over estimated the range of Lora and the amount of data which can be sent as part of their fair use policy. I wanted to cache data when there was no connection then upload when it found a gateway. It did spark an interesting discussion about using the motion sensor in the boat to sense when it is at the crest of a wave to ensure it has the best chance to get a connection though. I may still add Lora as a backup since it is cheap and very low power.
This is it so far. Nothing physical, all just thoughts, ideas and ambition!
I can’t wait to see some progress photos of your build on the blog site!