My boys and I are using an Android phone, solar panel, and a bluetooth relay controller to make an autonomous solar robot boat. The phone has display, touch screen, GPS, compass, clock, Internet, and bluetooth. It also has a really great software development environment in App Inventor. The display/touch screen make testing really nice. We can walk around with it showing arrows pointing the way it wants to go and spinning images of propellers on the left and right as it would be controlling the real propellers. So debugging was easier than if we only had the full hardware to test on.
More info at www.islandboys.ai
We can send Morse code with the light or with the horn. The horn is scary loud for inside a house.
The boat is working and motoring around the bay.
The phone/robot uploads GPS and other information to google in real time and google updates a map of the track in real time so anyone can see a map of what the robot is doing on the web.
The hardware is very simple really. There are a couple extra things on the drawing below. This drawing shows an electromagnet (which has not come in the mail yet) and a bluetooth speaker which we have not ordered and may not bother with. Also, I went with a smaller relay controller with just 4 relays as the 8 relay can not just get power from a USB. I put a red light on the relay the left motor is on and green light on the same relay as the right motor. So just watching the boat you can tell how much it is using each motor. A really bright white LED is on the 3rd relay. The horn is on the 4th relay. When I get the electromagnet I will put it on the same relay as the horn. I will turn on the electromagnet to push away a regular magnet (or at least that is the current plan) to separate from another boat.
The drawing was simplified a bit by not showing the 12 volt lines going to each of the relays or the ground lines going to the motors, lights, etc. For it to really work you need those wires too. :-)
We have a page with links to most of the parts for this project on Amazon, so it would not be too hard for someone to copy the electronics. We are trying to crowdfund a larger autonomous solar robot boat and the reward for a $50 donation is a copy of our source code. Our App Inventor software is really easy to use or modify. Our software could work with whatever sort of boat design you wanted as long as it had two motors. If you did a monohul you might want to put some space between the motors. So this is a really cool father-son project that is not really that hard.
This is a companion discussion topic for the original entry at https://community.robotshop.com/robots/show/autonomous-solar-robot-boat
Motor mount and stuffing box
Mounting the motor and what stuffing box to buy or make is still an issue. I ordered 2 stuffing boxes but Amazon says they are 2 lbs each. If this is true they are too heavy. It may be true as many of the power boats use really powerful engines and so could need a strong driveshaft and stuffing box. Our motors are only 7 watt. If anyone has any advice on how to do this without too much weight we would appreciate any help.
stuffing box
The motor is 38 mm in diameter. It is a 7 watt geared motor. Runs at 3000 RPM Shaft is 5 mm.
The propeller in 47 mm and pitch of 1.4 inches. Wants a 3/16 inch shaft with a notch. I found a flexible 3/16 inch shaft but no notch. I tried crazy glue and it seems to hold it so far.
The tube has to be metal to last, right? I read someplace that a brass tube would be good. I could not locate anything close to the right size on this little island (population about 14,000 means not as wide a selection of stores). And you really need a bushing at each end that fits the tube and the shaft. It looked like I could not make my own with parts here, but I had a hard time finding a stuffing box on Amazon and am worried that the one I found is too heavy. Takes a couple weeks for packages to get here by boat.
If you had to make a shaft and tube from stuff you can get at a small hardware store, could it be done? What would you look for?
I am not having much luck finding these on Amazon. Am I using the wrong keywords and really they are there?
Or do I need to go someplace else on the Internet for these?
Prop Shafting
Cool project. My local hardware stores sell brass tubing and rods of various diameters, roughly .3M long for a few bucks. You’ll have to experiment. Also, the “shaft” can be a tube. Hobby shops specialize in this sort of hardware. Hope this helps.
Thanks
There are no hobby shops here. I have a bit more searching at hardware stores. Is there an online place that has a good selection?
Thanks.
"r/c boat propeller shaft and tube" search terms
"r/c boat propeller shaft and tube" on ebay turned up some pricey subassemblies from a seller in Russia. But I imagine everything is slow and pricey in the Carribean, so Ace Hardware’s brass tubing and Amazon’s sellers may or may not be priced out of line. By the way, are Caribean waters still so clear they’re almost invisible?
The water is nice
Yes, the water is very clear and nice and warm. I think my next version of this will be sort of kayak scale so I can ride around on it. Like to be out on the water.
Copper flexible pipe
I found some flexible copper pipe the right inside diameter for my shaft. Put on some marine greese and the motor spins the prop nicely. My plan is to support it with some wood and try it out.
Long term I don’t think copper in salt water is a good idea, but I just want to see this boat move.
Still waiting for stuffing boxes I ordered to get here.
Cool
I think that what you’re doing is really neat.
Thanks!
Thanks! We have raised enough money to put electronics on the second (orange) boat. So I ordered those today. I can’t wait to have 2 of these motoring around in a little train. And I want to send them to another island and back. That will be cool.
JMEMantzel’s fibreglass boat
This guy is solving some similar problems with building a (non-autonomous) solar-powered boat without a lot of money or easy access to fancy stuff. He’s making everything from fibreglass, might be worth a look? https://www.youtube.com/user/JMEMantzel/videos (JMEMantzel on youtube)
Phones as hobbyist robotics platform
Btw, I think your use of a phone as source of brains and sensors for the robot is inspired. It really depends which problems you are most interested in solving - the phone provides a lot of what you need right out of the box, with good software support. And as a father I know the need for rapid results when doing projects with kids. Its an inspiring project, thanks for posting.
Very cool solar boat
I am sure solar boats will be much more popular over time. They make so much sense. Here is the link to his very cool solar boat:
https://www.youtube.com/watch?v=9z4RRn-LXhs
Thanks
Yes. I am very happy that App Inventor has been so much fun to work with. And the boys get it and like it. I tried to move to Java and they were not happy with that idea, so we have stayed with App Inventor. For the larger Quadmaran-10 I really want to do image understanding so we can have two boats autonomously connect together, use the phone camera, use the phone LED, and check the battery on the phone. App Inventor can’t do these things. I found another app I can call to check the battery, so we have that function, but the rest are reason enough to move for the next robot. If the kids really hate it we can just do these parts in Java and keep the rest of the function in App Inventor.
Ya, for a boat a phone is just the perfect thing. It has gyros, acceleration sensors, GPS, compass, SMS, internet, etc. Since it needs no inputs from the rest of the hardware we can do a very good test of the software just walking around with the phone. On the maiden autonomous voyage I just put it in the water and let it go before the boys even got in the kayak because I was very confident that the software would work.
And solar is so perfect for boats. For 3.5 lbs I have 50 watts as long as the sun is out. Fantastic.
I took off the water-break as it was about 2 lbs and I no longer feel the need for the training wheels. :-) Also, I have changed the software so when it is doing a “ParkBoat” command it turns 90 degrees to the wind. Tested by walking around and it works. Note the phone has no wind sensor, so kind of cool that it works, eh? It really turns 90 degrees to a line going to the point it is supposed to park near. By doing this it ends up downwind of the point and 90 degrees to the wind. Look forward to testing this new ParkBoat method in the water next week. Also, the boat should go a bit faster as 2 lbs is a lot for this boat.
Scaling up so humans can ride with autopilot
We have a 12 foot laser sailboat and plan to put 2 trolling motors on this (and remove sail). We will control these with the Android phone just like this autonomous boat above, via bluetooth. Then we can ride around with the phone driving on autopilot.
My plan is to use a bluetooth motor controller and a 40 amp Solid State Relay for each trolling motor. Anyone see any problem with my plan? Is there a better way?
https://www.amazon.com/gp/product/B00N3IP0LA/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1
http://www.amazon.com/gp/product/B00HUBZO7Q?psc=1&redirect=true&ref_=oh_aui_detailpage_o02_s01
If/when/after we get everything else working we will probably add solar to this.
Thanks.
